,,manual ,,= ,,! ,,solution ,,( ,,milit>y ,,ciph]s ,,by ,,p>k] ,,hitt ,capta9 ( ,infantry1 ,u4 ,s4 ,a4 ,,press ,,( ,,! ,,army ,,s]vice ,,s*ools ,=t ,leav5wor?1 ,kansas #aiaf ,,manual ,,= ,,! ,,solution ,,( ,,milit>y ,,ciph]s ,,by ,,p>k] ,,hitt ,capta9 ( ,infantry1 ,unit$ ,/ates ,army ,,introduction ,! hi/ory ( w> teems ) occasions :]e ! int]ception ( dispat*es & ord]s writt5 9 pla9 language has result$ 9 defeat & disa/] = ! =ce ^: int5tions ?us became kn[n at once to ! enemy4 ,= ?is reason1 prud5t g5]als h us$ ciph] & code messages f "t immemorial4 ,! necessity = exact expression ( ideas practically excludes ! use ( codes = milit>y "w al?\gh x is possible t a special tactical code might be useful = prep>ation ( tactical ord]s4 ,x is necess>y !re=e to fall back on ciph]s = g5]al milit>y "w if secrecy ( communication is to be fairly well assur$4 ,x may z well be /at$ "h t no practicable milit>y ciph] is ma!matically indeciph]able if int]cept$2 ! mo/ t c be expect$ is to delay = a long] or %ort] "t ! deciph]+ ( ! message by ! int]ceptor4 ,! capture ( mess5g]s is no long] ! only means available to ! enemy = ga9+ in=mation z to ! plans ( a comm&]4 ,all radio messages s5t out c be copi$ at ho/ile /ations )9 radio range4 ,if ! enemy c get a f9e wire )9 "o hundr$ feet ( a buzz] l9e or )9 ?irty feet ( a telegraph l9e1 ! message c be copi$ by induction4 ,messages pass+ ov] comm]cial telegraph l9es1 & ev5 ov] milit>y l9es1 c be copi$ by spies 9 ! (fices4 ,on telegraph l9es ( a p]man5t nature x is possible to in/all high spe$ automatic s5d+ & receiv+ ma*9es & ?us prev5t surreptiti\s copy+ ( messages1 b no?+ b a secure ciph] w s]ve ) o!r means ( communication4 ,x is n alone ! body ( ! message :i* %\ld be 9 ciph]4 ,x is equally important t1 dur+ transmission1 ! preamble1 place f1 date1 address & signature be enciph]$2 b ?is %\ld be done by ! s5d+ op]ator & ^! p>ts mu/1 ( c\rse1 be deciph]$ by ! receiv+ op]ator be=e deliv]y4 ,a special op]ators' ciph] %\ld be us$ = ?is purpose b x is difficult to prescribe "o t w\ld be simple en\gh = ! av]age op]ator1 fa/ & yet reasonably safe4 ,"s =m ( rot>y ciph] ma*9e w\ld seem to be be/ suit$ = ?is special purpose4 ,x is unnecess>y to po9t out t a ciph] :i* c be deciph]$ by ! enemy 9 a few h\rs is worse ?an useless4 ,x requires a surpris+ly long "t to enciph] & deciph] a message1 us+ ev5 ! simple/ k9d ( ciph]1 & errors 9 transmission ( ciph] matt] by wire or radio are un=tunately too common4 ,k]ckh(fs has /at$ t a milit>y ciph] %\ld fulfill ! foll[+ requirem5ts3 #a/4 ,! sy/em %\ld be mat]ially1 if n ma!matically1 indeciph]able4 #b;d4 ,x %\ld cause no inconv5i5ce if ! app>atus & me?ods fall into ! h&s ( ! enemy4 #c;d4 ,! key %\ld be su* t x c\ld be communicat$ & rememb]$ )\t ! necessity ( writt5 notes & %\ld be *angeable at ! w ( ! correspond5ts4 #d?4 ,! sy/em %\ld be applicable to telegraphic correspond5ce4 #e?4 ,! app>atus %\ld be easily c>ri$ & a s+le p]son %\ld be able to op]ate x4 #f?4 ,f9ally1 9 view ( ! circum/ances "u :i* x mu/ be us$1 ! sy/em %\ld be an easy "o to op]ate1 dem&+ nei!r m5tal /ra9 nor k ( a long s]ies ( rules4 ,a brief consid]ation ( ^! six conditions mu/ lead to ! conclusion t !re is no p]fect milit>y ciph]4 ,! fir/ requirem5t is ! "o mo/ (t5 ov]look$ by ^? prescrib+ ! use ( any giv5 ciph] &1 ev5 if n ov]look$1 ! indeciph]ability ( any ciph] likely to be us$ = milit>y purposes is usually va/ly ov]e/imat$ by ^? prescrib+ ! use ( x4 ,if ?is 7 n true1 !re w\ld h be5 nei!r mat]ial =1 nor purpose 91 ! prep>ation ( ^! notes4 ,( ! hundr$s ( actual ciph] messages exam9$ by ! writ]1 at lea/ n9e-t5?s h be5 solv$ by ! me?ods to be set =?4 ,^! messages 7 prep>$ by ! me?ods 9 use by ! ,unit$ ,/ates ,army1 ! v>i\s ,mexican armies & _! secret ag5ts1 & by o!r me?ods 9 common use4 ,! usual failure has be5 ) v %ort messages4 ,=eign works consult$ lead to ! belief t _m ,european p[]s h us$1 = milit>y purposes1 ciph] me?ods :i* v>y f an extreme simplicity to a complexity :i* is m app>5t ?an real4 ,:at effect rec5t ev5ts h _h on ?is matt] rema9s to be se54 ,x is en\gh t ! ciph] exp]ts ( practically e ,european c\ntry h appeal$ to ! milit>y au?orities ( _! respective c\ntries "t & aga9 to d away ) ^! useless ciph]s & to adopt some?+ :i* (f]s m security1 ev5 at ! exp5se ( o!r consid]ations4 ,! ciph] ( ! amateur1 or ( ! non-exp]t :o makes "o up = "s special purpose1 is almo/ sure to fall into "o ( ! classes ^: solution is an easy matt]4 ,! human m9d works along ! same l9es1 9 spite ( an attempt at orig9ality on ! "p ( ! individual1 & ?is is p>ticul>ly true ( ciph] "w because !re are s few s\rces ( in=mation available4 ,9 o!r words1 ! av]age man1 :5 he sits d[n to evolve a ciph]1 has no?+ to improve ^u2 he inv5ts & !re is no "o to tell him t 8 inv5tion is1 9 pr9ciple1 hundr$s ( ye>s old4 ,! ciph]s ( ! ,abb ,tri!me1 #adii1 are ! basis ( mo/ ( ! mod]n sub/itution ciph]s4 ,9 view ( ^! facts1 no message %\ld be consid]$ indeciph]able4 ,v %ort messages are (t5 v difficult & may easily be entirely beyond ! possibility ( analysis & solution1 b x is surpris+ :at c be done1 at times1 ) a message ( only a few words4 ,9 ! ev5t ( active op]ations1 ciph] exp]ts w be 9 dem& at once4 ,l all o!r exp]ts1 ! ciph] exp]t is n born or made 9 a day2 & x is only con/ant "w ) ciph]s1 comb9$ ) a ?or\gh k ( _! und]ly+ pr9ciples1 t w make "o wor?y ( ! "n4 ,,*apt] ,i ,,equipm5t ,,= ,,ciph] ,,"w ,success 9 deal+ ) unkn[n ciph]s is measur$ by ^! f\r ?+s 9 ! ord] nam$2 p]sev]ance1 c>eful me?ods ( analysis1 intuition1 luck4 ,! ability at lea/ to read ! language ( ! orig9al text is v desirable b n ess5tial4 ,ciph] "w w h little p]man5t attraction = "o :o expects results at once1 )\t labor1 = !re is a va/ am\nt ( purely r\t9e labor 9 ! prep>ation ( frequ5cy tables1 ! re>rangem5t ( ciph]s = exam9ation1 & ! trial & fitt+ ( lett] to lett] be=e ! message beg9s to appe>4 ,! me?ods ( analysis giv5 9 ^! notes cov] only ! simpl] v>ieties ( ciph] & x is1 ( c\rse1 impossible to enum]ate all ! v>ieties ( ^!4 ,x is believ$ t ! me?ods laid d[n are s\nd & sev]al ye>s ( successful "w along ?is l9e w\ld seem to confirm ?is belief4 ,= m advanc$ "w !re is no rec\rse b to /udy ! ,european au?orities ^: writ+s are mo/ly 9 ,fr5*1 ,g]man1 & ,italian &1 un=tunately1 are r>ely available 9 ,engli% translations4 ,"u intuition mu/ be includ$ a k ( ! g5]al situation &1 if possible1 ! special situation :i* l$ to ! s5d+ ( ! ciph] message4 ,! k or guess t a c]ta9 ciph] message conta9s a p>ticul> ^w1 (t5 leads to its solution4 ,z to luck1 !re is ! old m9]'s prov]b3 ,gold is :]e y f9d x4 ,! equipm5t = an (fice1 :]e mu* ciph] "w is h&l$1 w n[ be consid]$4 ,! casual work] ) ciph]s c get along ) mu* less1 b ! me?ods ( fil+ & keep+ a record ( all messages /udi$ %\ld be foll[$ :]ev] possible4 ,! int]*ange ( results betwe5 individuals & betwe5 (fices %\ld be enc\rag$ &1 9 "t ( active op]ations1 %\ld be m&atory4 ,an enemy may be us+ ! same ciph] 9 widely sep>at$ p>ts ( ! zone ( op]ations & x is useless labor to h _m ciph] (fices work+ on int]cept$ messages1 all 9 ! same ciph]1 :5 "o (fice may h ! solution t w apply to all ( !m4 ,ciph] "w requires conc5tration & quiet & (t5 mu/ proce$ )\t reg>d to h\rs4 ,! (fice %\ld be *os5 ) ^! po9ts 9 m9d4 ,a cl]ical =ce is desirable & ev5 necess>y if !re is mu* "w to d4 ,! cl]k or cl]ks c soon be tra9$ to d ! r\t9e "p ( ! analysis4 ,x is believ$ t ea* ,field ,army %\ld h su* an (fice :]e all ciph]s int]cept$ by =ces "u comm& ( ! ,field ,army ,comm&] %\ld be s5t at once = exam9ation4 ,?is "w naturally falls to ! ,intellig5ce section ( ! ,g5]al ,/aff at ?is headqu>t]s4 ,a special radio /ation1 ) receiv+ in/rum5ts only1 %\ld be an adjunct to ?is (fice & its function %\ld be to copy all ho/ile radio messages :e!r 9 ciph] or pla9 text4 ,su* a radio /ation requires b a small ant5na2 "o ( ! pack set type or any amateur's ant5na is suffici5t1 & ! /ation in/rum5ts c be easily c>ri$ 9 a suit case4 ,?ree ?or\ghly compet5t op]ators %\ld be provid$1 s t ! /ation c be li/5+ 9 dur+ ! entire tw5ty-f\r h\rs4 ,! (fice %\ld be provid$ ) tables ( frequ5cy ( ! language ( ! enemy1 cov]+ s+le lett]s & digraphs2 a diction>y & gramm> ( t language2 copies ( ! ,w> ,dep>tm5t ,code1 ,we/]n ,union ,code & any o!r available ones2 types ( app>atus or1 at lea/1 data on app>atus & ciph] me?ods 9 use by ! enemy2 & a safe fil+ cab9et & c>d index = fil+ messages exam9$4 ,a typewrit] is also desirable4 ,! (fice "w on a ciph] "u exam9ation %\ld be done on pap] ( a /&>d & uni=m size4 ,pr9t$ =ms conta9+ tw5ty-six rul$ l9es & a v]tical alphabet are conv5i5t & save "t 9 prep>ation ( frequ5cy tables4 ,any new ciph] me?ods :i* are f\nd to be 9 use by ! enemy %\ld1 :5 solv$1 be communicat$ to all simil> (fices 9 ! ,army = _! in=mation4 ,unless an enemy 7 exce$+ly vigilant & *ang$ keys & me?ods frequ5tly1 su* an (fice w\ld1 9 a few days1 be 9 a position to disclose completely all int]cept$ ciph] communications ( ! enemy ) practically no delay4 ,,*apt] ,,ii ,,pr9ciples ,,( ,,me*anism ,,( ,a ,,writt5 ,,language ,) a few exceptions1 notably ,*9ese1 all mod]n languages are con/ruct$ ( words :i* 9 turn are =m$ f lett]s4 ,9 any giv5 language ! numb] ( lett]s1 & _! conv5tional ord] is fix$4 ,?us ,engli% is writt5 ) #bf lett]s & _! conv5tional ord] is ,a1 ,b1 ,c1 ,d1 ,e1 etc4 ,"s lett]s are us$ v frequ5tly & o!rs r>ely4 ,9 fact1 if t5 ?\s& consecutive lett]s ( a text be c\nt$ & ! frequ5cy ( occurr5ce ( ea* lett] be not$1 ! numb]s f\nd w be practically id5tical ) ^? obta9$ f any o!r text ( t5 ?\s& lett]s 9 ! same language4 ,! relative proportion ( occurr5ce ( ! v>i\s lett]s w also hold approximately = ev5 v %ort texts4 ,su* a c\nt ( a l>ge numb] ( lett]s1 :5 x is put 9 ! =m ( a table1 is kn[n z a frequ5cy table4 ,e language has its own di/9ctive frequ5cy table &1 = any giv5 language1 ! frequ5cy table is almo/ z fix$ z ! alphabet4 ,!re are m9or diff]5ces 9 frequ5cy tables prep>$ f texts on special subjects4 ,= example1 if ! text be newspap] matt]1 ! frequ5cy table w diff] slightly f "o prep>$ f milit>y ord]s & w also diff] slightly f "o prep>$ f telegraph messages4 ,b ^! diff]5ces are v slight z comp>$ ) ! diff]5ces betwe5 ! frequ5cy tables ( two diff]5t languages4 ,aga9 !re is a fix$ ratio ( occurr5ce ( e lett] ) e o!r = any language & ?is1 put 9 table =m1 con/itutes a table ( frequ5cy ( digraphs4 ,9 ! same way a table ( trigraphs1 %[+ ! ratio ( occurr5ce ( any ?ree lett]s 9 sequ5ce1 c\ld be prep>$1 b su* a table w\ld be v ext5sive & a c\nt ( ! m common ?ree lett] comb9ations is usually us$4 ,o!r tables1 su* z frequ5cy ( initial & f9al lett]s ( words1 might be ( value b ! common practice is to put ciph] text into gr\ps ( five or t5 lett]s ea* & elim9ate ^w =ms4 ,?is is almo/ a necessity 9 telegraphic & radio communication to enable ! receiv+ op]ator to *eck correct receipt ( a message4 ,he mu/ get five lett]s1 nei!r m nor less1 p] ^w or he is sure a mi/ake has be5 made4 ,!re is little difficulty1 z a rule1 9 re/or+ ^w =ms 9 ! deciph]$ message4 ,we w n[ take up1 9 ord]1 ! v>i\s frequ5cy tables & l+ui/ic peculi>ities ( ,engli% & ,spani%4 ,frequ5cy tables = ,fr5*1 ,g]man1 & ,italian = s+le lett]s w foll[4 ,all frequ5cy tables h be5 re-calculat$ f at lea/ t5 ?\s& lett]s ( text & comp>$ ) exi/+ tables4 ,no m>k$ diff]5ce has be5 f\nd 9 any case betwe5 ! re-calculat$ tables & ^? already 9 use4 ,data = ,solution ( ,ciph]s 9 ,engli% ,table ,i4--,normal frequ5cy table4 ,frequ5cy = t5 ?\s& lett]s & = two hundr$ lett]s4 ,?is latt] is put 9 graphic =m & is necess>ily an approximation4 ,tak5 f milit>y ord]s & reports1 ,engli% text4 #aj1jjj ,lett]s #bjj ,lett]s ,a #ggh #af #aaaaaaaaaaaaaaaa ,b #ada #c #aaa ,c #bif #f #aaaaaa ,d #djb #h #aaaaaaaa ,e #abgg #bf #aaaaaaaaaaaaaaaaaaaaaaaaaa ,f #aig #d #aaaa ,g #agd #c #aaa ,h #eie #ab #aaaaaaaaaaaa ,i #ffg #ac #aaaaaaaaaaaaa ,j #ea #a #a ,k #gd #b #aa ,l #cgb #g #aaaaaaa ,m #bhh #f #aaaaaa ,n #fhf #ad #aaaaaaaaaaaaaa ,o #hjg #af #aaaaaaaaaaaaaaaa ,p #bbc #d #aaaa ,q #h ,r #fea #ac #aaaaaaaaaaaaa ,s #fbb #ab #aaaaaaaaaaaa ,t #hee #ag #aaaaaaaaaaaaaaaaa ,u #cjh #f #aaaaaa ,v #aab #b #aa ,w #agf #c #aaa ,x #bg ,y #aif #d #aaaa ,z #ag ,v[els ,,aei\ #ch4cg2 consonants ,,lnr/ #ca4hf2 consonants ,,jkqxz #a4gg4 ,! v[els may be safely tak5 z #dj1 consonants ,,lnr/ z #cj & consonants ,,jkqxz z #b4 ,ord] ( lett]s3 ,e ,t ,o ,a ,n ,i ,r ,s ,h ,d ,l ,u ,c ,m ,p ,f ,y ,w ,g ,b ,v ,k ,j ,x ,z ,q4 ,table ,,ii4--,frequ5cy table = telegraph messages1 ,engli% text4 ,?is table v>ies slightly f ! /&>d frequ5cy table because ! common ^w ! is r>ely us$ 9 telegrams & !re is a t5d5cy to use long] & less common words 9 prep>+ telegraph messages4 #aj1jjj ,lett]s #bjj ,lett]s ,a #hac #af #aaaaaaaaaaaaaaaa ,b #adi #c #aaa ,c #cjf #f #aaaaaa ,d #dag #h #aaaaaaaa ,e #acai #bf #aaaaaaaaaaaaaaaaaaaaaaaaaa ,f #bje #d #aaaa ,g #bja #d #aaaa ,h #chf #h #aaaaaaaa ,i #gaa #ad #aaaaaaaaaaaaaa ,j #db #a #a ,k #hh #b #aa ,l #cib #h #aaaaaaaa ,m #bgc #f #aaaaaa ,n #gah #ad #aaaaaaaaaaaaaa ,o #hdd #ag #aaaaaaaaaaaaaaaaa ,p #bdc #e #aaaaa ,q #ch #a #a ,r #fgg #ad #aaaaaaaaaaaaaa ,s #fef #ac #aaaaaaaaaaaaa ,t #fcd #ac #aaaaaaaaaaaaa ,u #cba #f #aaaaaa ,v #acf #c #aaa ,w #aff #c #aaa ,x #ea #a #a ,y #bjh #d #aaaa ,z #f ,9 ?is table ! v[els ,,aei\ #dj4jh1 consonants ,,lnr/ #cj4gg & consonants ,,jkqxz #b4be4 ,ord]s ( lett]s3 ,e ,o ,a ,n ,i ,r ,s ,t ,d ,l ,h ,u ,c ,m ,p ,y ,f ,g ,w ,b ,v ,k ,x ,j ,q ,z4 ,table ,,iii4--,table ( frequ5cy ( digraphs1 duals or pairs 7,engli%74 ,?is table 0 prep>$ f #bj1jjj lett]s1 b ! figures %[n are on ! basis ( #b1jjj lett]s4 ,= ?is reason !y are1 to a c]ta9 ext5t1 approximate2 t is1 m]ely because no figures are %[n = c]ta9 comb9ations1 we %\ld n assume t su* comb9ations nev] occur b r t !y are r>e4 ,! lett]s 9 ! horizontal l9e at ! top & bottom are ! lead+ lett]s2 ^? 9 ! v]tical columns at ! sides are ! foll[+ lett]s4 ,?us 9 two ?\s& lett]s we may expect to f9d ,,ah once & ,,ha tw5ty-six times4 ,a ,b ,c ,d ,e ,f ,g ,h ,i ,j ,k ,l ,m ,n ,o ,p ,q ,r ,s ,t ,u ,v ,w ,x ,y ,z ,a #a #g #aj #bb #c #b #bf #d #b #b #g #h #aa #b #i #ac #ab #i #b #d #a #ab ,b #e #a #b #a #a #a #a #b #b #a #c #a ,c #f #a #a #ad #b #aa #aa #c #b #c #a #a #a #a ,d #f #ab #cj #a #b #d #cj #a #d #a #a #a #a #c ,e #aa #ad #af #ab #b #f #cc #aj #b #f #ah #ad #ab #a #g #cf #aa #ab #b #af #e #a #a ,f #c #b #h #b #a #b #b #a #c #be #c #a #a #a ,g #d #a #c #b #aa #b #c #a ,h #a #aa #b #d #a #d #a #b #a #a #b #aj #ej #c #b ,i #b #a #d #ab #f #e #a #ab #a #e #i #h #ab #a #c #ab #ac #bb #b #c #f #a #a ,j #a ,k #a #a #b #b #a #a ,l #ad #f #b #a #f #a #a #a #f #i #c #f #c #c #b #c #e ,m #g #c #ac #b #b #c #d #a #aj #d #a #a #b ,n #ch #c #be #b #a #ca #c #b #b #ci #d #c #aa #b ,o #a #a #ab #d #h #h #c #ab #ah #b #d #g #h #c #g #ac #ae #bb #b #f #a #e ,p #b #a #h #a #b #d #b #c #b #a #h #a #d #c #a ,q #b #a #a #a ,r #af #a #c #c #dj #c #f #b #f #a #b #a #be #h #b #b #h #aa #b ,s #af #a #c #be #a #b #ag #a #b #a #ab #g #b #i #aa #f #aa #a #f ,t #be #a #c #ab #ac #e #b #c #bj #b #a #bd #h #b #af #bj #aa #f #b #b #g ,u #a #b #a #f #a #c #b #b #c #c #a #ag #a #e #c #e #e #a ,v #c #a #e #e #c #b #e #a ,w #a #b #h #a #a #a #a #b #d #b #c #c ,x #a #d #b #a #a ,y #c #b #b #d #a #a #h #a #b #a #c #a #g ,z #a #a #a ,a ,b ,c ,d ,e ,f ,g ,h ,i ,j ,k ,l ,m ,n ,o ,p ,q ,r ,s ,t ,u ,v ,w ,x ,y ,z ,table ,,iv4--,ord] ( frequ5cy ( common pairs to be expect$ 9 a c\nt ( #b1jjj lett]s ( milit>y or semi-milit>y ,engli% text4 7,bas$ on a c\nt ( #bj1jjj lett]s74 ,,? #ej ,,at #be ,,/ #bj ,,er #dj ,,en #be ,,io #ah ,,on #ci ,,es #be ,,le #ah ,,an #ch ,,( #be ,,is #ag ,,re #cf ,,or #be ,,ou #ag ,,he #cc ,,nt #bd ,,ar #af ,,9 #ca ,,ea #bb ,,z #af ,,ed #cj ,,ti #bb ,,de #af ,,nd #cj ,,to #bb ,,rt #af ,,ha #bf ,,x #bj ,,ve #af ,table ,v4--,table ( recurr5ce ( gr\ps ( ?ree lett]s to be expect$ 9 a c\nt ( #aj1jjj lett]s ( ,engli% text4 ,,! #hi ,,tio #cc ,,edt #bg ,,& #ed ,,= #cc ,,tis #be ,,?a #dg ,,nde #ca ,,(t #bc ,,ent #ci ,,has #bh ,,/h #ba ,,ion #cf ,,nce #bg ,,m5 #bj ,table ,,vi4--,table ( frequ5cy ( occurr5ce ( lett]s z initials & f9als ( ,engli% words4 ,bas$ on a c\nt ( #d1jjj words2 ?is table gives ! figures = an av]age #ajj words & is necess>ily an approximation1 l ,table ,,iii4 ,engli% words are d]iv$ f s _m s\rces t x is n impossible = any lett] to occur z an initial or f9al ( a ^w1 al?\gh ,q1 ,x & ,z are r>e z initials & ,b1 ,i1 ,j1 ,q1 ,v1 ,x & ,z are r>e z f9als4 ,lett]s ,a ,b ,c ,d ,e ,f ,g ,h ,i ,j ,k ,l ,m ,n ,o ,p ,q ,r ,s ,t ,u ,v ,w ,x ,y ,z ,initial #i #f #f #e #b #d #b #c #c #a #a #b #d #b #aj #b - #d #e #ag #b - #g - #c - ,f9al #a - - #aj #ag #f #d #b - - #a #f #a #i #d #a - #h #i #aa #a - #a - #h - ,x is practically impossible to f9d five consecutive lett]s 9 an ,engli% text )\t a v[el & we may expect f "o to ?ree ) two z ! g5]al av]age4 ,9 any tw5ty lett]s we may expect to f9d f #f to #i v[els ) #h z an av]age4 ,among !mselves ! relative frequ5cy ( occurr5ce ( ea* ( ! v[els1 7includ+ ,y :5 a v[el7 is z foll[s3 ,a1 #ai4e ,e1 #cb4j ,i1 #af4g ,o1 #bj4b ,u1 #h4j ,y1 #c4f ,! =ego+ tables give all ! ess5tial facts ab\t ! me*anism ( ! ,engli% language f ! /&po9t ( ! solution ( ciph]s4 ,! use to be made ( ^! tables w be evid5t :5 ! solution ( diff]5t types ( ciph]s is tak5 up4 ,data = ! ,solution ( ,ciph]s 9 ,spani% ,! ,spani% language is writt5 ) ! foll[+ alphabet3 ,a ,b ,c ,,* ,d ,e ,f ,g ,h ,i ,j ,l ,,ll ,m ,n ,o ,p ,q ,r ,,rr ,s ,t ,u ,v ,x ,y ,z :ile ! exact s5se (t5 dep5ds ^u ! use ( acc5ts ov] ! v[els4 ,h[ev]1 9 ciph] "w x is exce$+ly inconv5i5t to use ! p]man5t digraphs1 ,,*1 ,,ll & ,,rr & !y d n appe> z su* 9 any specim5s ( ,spani% or ,mexican ciph] exam9$4 ,acc5t$ v[els & are also n f\nd & we may1 9 g5]al1 say t a ciph] ^: text is ,spani% w be prep>$ ) ! foll[+ alphabet3 ,a ,b ,c ,d ,e ,f ,g ,h ,i ,j ,l ,m ,n ,o ,p ,q ,r ,s ,t ,u ,v ,x ,y ,z & ! receiv] mu/ supply ! acc5ts & ! tilde ov] ! ,n to con=m to ! g5]al s5se4 ,h[ev]1 _m ,mexican ciph] alphabets conta9 ! lett]s ,k & ,w4 ,?is is p>ticul>ly true ( ! ciph]s 9 use by secret s]vice ag5ts :o mu/ be prep>$ to h&le words l ,,new ,,york1 ,,wilson & ,,wa%+ton4 ,! lett]s ,k & ,w w1 h[ev]1 h a negligible frequ5cy except 9 %ort messages :]e words l ^! occur m ?an once4 ,9 ?is connection1 if a ciph] conta9s ,mexican geographical names l ,,*ihuahua1 ,,mexico1 ,,muzquiz1 ! lett]s ,h1 ,x & ,z w h a some:at exagg]at$ frequ5cy4 ,9 ,spani%1 ! lett] ,q is always foll[$ by ,u & ! ,u is always foll[$ by "o ( ! o!r v[els1 ,a1 ,e1 ,i or ,o4 ,z ,,que or ,,qui occurs n infrequ5tly 9 ,spani% text1 p>ticul>ly 9 telegraphic correspond5ce1 x is well wor? not+ t1 if a ,q occurs 9 a transposition ciph]1 we mu/ connect x ) ,u & ano!r v[el4 ,! clue to sev]al transposition ciph]s has be5 f\nd f ?is simple relation4 ,table ,,vii4--,normal frequ5cy table = milit>y ord]s & reports1 calculat$ on a basis ( #aj1jjj lett]s ( ,spani% text4 ,! graphic =m is on a basis ( #bjj lett]s4 #aj1jjj ,lett]s #bjj ,lett]s ,a #aceb #bg #aaaaaaaaaaaaaaaaaaaaaaaaaaa ,b #ajb #b #aa ,c #dgd #i #aaaaaaaaa ,d #ebd #aj #aaaaaaaaaa ,e #adjb #bh #aaaaaaaaaaaaaaaaaaaaaaaaaaaa ,f #ia #b #aa ,g #acg #c #aaa ,h #ajb #b #aa ,i #fjf #ab #aaaaaaaaaaaa ,j #da #a #a ,l #eag #aj #aaaaaaaaaa ,m #cjj #f #aaaaaa ,n #fai #ab #aaaaaaaaaaaa ,o #hah #af #aaaaaaaaaaaaaaaa ,p #beg #e #aaaaa ,q #hg #b #aa ,r #gea #ae #aaaaaaaaaaaaaaa ,s #gbd #ad #aaaaaaaaaaaaaa ,t #dbb #h #aaaaaaaa ,u #chg #g #aaaaaaa ,v #he #b #aa ,x #f ,y #ajc #b #aa ,z #db #a #a ,9 ?is table ! v[els ,,aei\ #de4fe2 consonants ,,lnr/ #cj4cc2 consonants ,,jkqxz #a4gf4 ,ord] ( lett]s3 ,e ,a ,o ,r ,s ,n ,i ,d ,l ,c ,t ,u ,m ,p ,g ,y 7,,bh7 ,f ,q ,v ,z ,j ,x4 ,table ,,viii4--,table ( frequ5cy ( digraphs1 duals or pairs1 ,spani% text4 ,l ,table ,,iii1 ?is table is on ! basis ( #b1jjj lett]s al?\gh prep>$ f a c\nt ( #bj1jjj lett]s4 ,= ?is reason x is1 to a c]ta9 ext5t an approximation2 t is1 m]ely because no figures are %[n = c]ta9 comb9ations1 we %\ld n assume t su* comb9ations nev] occur b r t !y are r>e4 ,! lett]s 9 ! horizontal l9es at ! top & bottom are ! lead+ lett]s2 ^? 9 ! v]tical columns at ! sides are ! foll[+ lett]s4 ,?us1 9 two ?\s& lett]s1 we may expect to f9d ,,ai twice & ,,ia tw5ty-?ree times4 ,a ,b ,c ,d ,e ,f ,g ,h ,i ,j ,l ,m ,n ,o ,p ,q ,r ,s ,t ,u ,v ,x ,y ,z ,a #i #d #ai #aa #e #f #ag #bc #ed #ah #i #c #bj #bi #aa #ba #h #f #b #e ,a ,b #f #c #a #d ,b ,c #bd #f #f #bd #e #c #h #h #i #e #b #b ,c ,d #ca #bi #c #ai #ac #aj #i #d ,d ,e #ab #b #f #ei #aj #a #e #g #b #ab #ah #bb #d #i #ch #be #bh #be #c #c ,e ,f #d #d #d #c #c #a ,f ,g #b #d #h #d #b ,g ,h #b #ab #aj #b #a ,h ,i #b #bc #af #e #b #c #aa #ac #f #aj #e #c ,i ,j #c #b #a ,j ,l #ba #c #f #ci #c #c #g #ba #e #f #ab #b #b ,l ,m #ab #f #e #a #f #ae #g #b #f #a ,m ,n #cb #df #b #h #cb #ab #b ,n ,o #bf #bb #b #f #c #d #i #af #b #h #bj #ae #g #aa ,o ,p #ac #c #b #d #i #b #g #d #aa ,p ,q #aa #e #a #b #c #a ,q ,r #dj #bg #b #d #d #cf #c #aa #ag #c ,r ,s #ci #eb #aj #g #ad #b #ad #c ,s ,t #e #ac #d #d #ah #e #f #cj ,t ,u #b #d #b #f #c #d #e #b #f #d #ag #ae #b #a ,u ,v #b #b #b #b #b #b ,v ,x ,x ,y #e #f #b #e #b #b ,y ,z #a #b #a #d #b ,z ,a ,b ,c ,d ,e ,f ,g ,h ,i ,j ,l ,m ,n ,o ,p ,q ,r ,s ,t ,u ,v ,x ,y ,z ,table ,,ix4--,ord] ( frequ5cy ( common pairs to be expect$ 9 a c\nt ( #b1jjj lett]s ( ,spani% milit>y ord]s & reports4 ,bas$ on ,table ,,viii4 ,,de #ei ,,on #cb ,,ac #bd ,,la #ed ,,ad #ca ,,ec #bd ,,es #eb ,,/ #cj ,,ci #bc ,,en #df ,,ed #bi ,,ia #bc ,,ar #dj ,,ra #bi ,,d #bb ,,z #ci ,,te #bh ,,ne #bb ,,el #ci ,,er #bg ,,al #ba ,,re #ch ,,co #bf ,,ll #ba ,,or #cf ,,se #be ,,pa #bj ,,an #cb ,,ue #be ,,po #bj ,alphabetic ,frequ5cy ,tables 7,truesdell7 ,frequ5cy ( occurr5ce 9 #a1jjj lett]s ( text3 ,lett] ,fr5* ,g]man ,italian ,portuguese ,a #hj #eb #aag #adj ,b #f #ah #f #f ,c #cc #ca #de #cd ,d #dj #ea #ca #dj ,e #aig #agc #abf #adb ,f #i #ba #aj #ab ,g #g #db #ag #aj ,h #f #da #f #aj ,i #fe #ha #aad #ei ,j #c #a #a #e ,k #a #aj #a ,l #di #bh #gb #cb ,m #ca #bj #cj #df ,n #gi #abj #ff #dh ,o #eg #bh #ic #aaj ,p #cb #h #cj #bh ,q #ab #a #c #af ,r #gd #fi #fd #fd ,s #ff #eg #di #hh ,t #fe #fj #fj #dc ,u #fb #ea #bi #df ,v #ba #i #bj #ae ,w #a #ae ,x #c #a #a #a ,y #b #a #a #a ,z #a #ad #ab #d ,ord] ( ,frequ5cy ,fr5* ,e ,a ,n ,r ,s ,i ,u ,o ,l ,d ,c ,p ,m ,v ,q ,f ,g ,b ,j ,y ,z ,t ,h ,x ,g]man ,e ,n ,i ,r ,t ,s ,a ,d ,g ,h ,c ,l ,f ,m ,b ,w ,z ,k ,v ,p ,j ,q ,x ,y ,u ,o ,italian ,e ,a ,i ,o ,l ,n ,r ,t ,s ,c ,d ,m ,u ,v ,g ,z ,f ,b ,q ,p ,h ,portuguese ,e ,a ,o ,s ,r ,i ,n ,m ,t ,d ,c ,l ,p ,q ,v ,f ,g ,b ,j ,z ,x ,y ,u ,h ,graphic ,frequ5cy ,tables ,frequ5cy ( occurr5ce 9 #bjj lett]s ( text4 ,fr5* ,a #af #aaaaaaaaaaaaaaaa ,b #b #aa ,c #f #aaaaaa ,d #aj #aaaaaaaaaa ,e #ci #aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa ,f #b #aa ,g #a #a ,h #a #a ,i #ac #aaaaaaaaaaaaa ,j #a #a ,k ,l #aj #aaaaaaaaaa ,m #f #aaaaaa ,n #af #aaaaaaaaaaaaaaaa ,o #aa #aaaaaaaaaaa ,p #f #aaaaaa ,q #b #aa ,r #ae #aaaaaaaaaaaaaaa ,s #ac #aaaaaaaaaaaaa ,t #ac #aaaaaaaaaaaaa ,u #ab #aaaaaaaaaaaa ,v #d #aaaa ,w ,x #a #a ,y ,z ,italian ,a #bc #aaaaaaaaaaaaaaaaaaaaaaa ,b #a #a ,c #i #aaaaaaaaa ,d #f #aaaaaa ,e #be #aaaaaaaaaaaaaaaaaaaaaaaaa ,f #b #aa ,g #c #aaa ,h #a #a ,i #bc #aaaaaaaaaaaaaaaaaaaaaaa ,l #ad #aaaaaaaaaaaaaa ,m #f #aaaaaa ,n #ac #aaaaaaaaaaaaa ,o #ai #aaaaaaaaaaaaaaaaaaa ,p #f #aaaaaa ,q ,r #ac #aaaaaaaaaaaaa ,s #aj #aaaaaaaaaa ,t #ab #aaaaaaaaaaaa ,u #f #aaaaaa ,v #d #aaaa ,x ,y ,z #b #aa ,g]man ,a #aj #aaaaaaaaaa ,b #d #aaaa ,c #f #aaaaaa ,d #aj #aaaaaaaaaa ,e #cb #aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa ,f #d #aaaa ,g #h #aaaaaaaa ,h #h #aaaaaaaa ,i #af #aaaaaaaaaaaaaaaa ,j ,k #b #aa ,l #f #aaaaaa ,m #d #aaaa ,n #bd #aaaaaaaaaaaaaaaaaaaaaaaa ,o #f #aaaaaa ,p #b #aa ,q ,r #ad #aaaaaaaaaaaaaa ,s #aa #aaaaaaaaaaa ,t #ab #aaaaaaaaaaaa ,u #aj #aaaaaaaaaa ,v #b #aa ,w #c #aaa ,x ,y ,z #c #aaa ,portuguese ,a #bh #aaaaaaaaaaaaaaaaaaaaaaaaaaaa ,b #a #a ,c #g #aaaaaaa ,d #h #aaaaaaaa ,e #bh #aaaaaaaaaaaaaaaaaaaaaaaaaaaa ,f #b #aa ,g #b #aa ,h #b #aa ,i #ab #aaaaaaaaaaaa ,j #a #a ,l #f #aaaaaa ,m #i #aaaaaaaaa ,n #aj #aaaaaaaaaa ,o #bb #aaaaaaaaaaaaaaaaaaaaaa ,p #f #aaaaaa ,q #c #aaa ,r #ac #aaaaaaaaaaaaa ,s #ah #aaaaaaaaaaaaaaaaaa ,t #i #aaaaaaaaa ,u #i #aaaaaaaaa ,v #c #aaa ,x ,y ,z #a #a ,,*apt] ,,iii ,,te*nique ,,( ,,ciph] ,,exam9ation ,9 "t ( active op]ations x is important t captur$ or int]cept$ ciph] messages rea* ! exam9+ (fice ) ! lea/ possible delay4 ,! text ( messages1 captur$ at a di/ance f ! exam9+ (fice1 %\ld be s5t to ! (fice by telegraph or telephone1 ! orig9al messages be+ =w>d$ to ! (fice z soon !reaft] z possible4 ,! preamble1 place f1 date1 address & signature1 give mo/ important clues z to ! language ( ! ciph]1 ! ciph] me?od probably us$1 & ev5 ! subject matt] ( ! message4 ,if ! :ole ( a telegraphic or radio message is 9 ciph]1 x is highly probable t ! preamble1 place f1 etc41 are 9 an op]ators' ciph] & are di/9ct f ! body ( ! message4 ,z ^! op]ators' ciph]s are necess>ily simple1 an attempt %\ld always be made to discov]1 by me?ods ( analysis to be set =? lat]1 ! exact ext5t ( ! op]ator's ciph] & !n to deciph] ! p>ts ( ! messages enciph]$ ) x4 ,9 milit>y messages1 we almo/ inv>iably f9d ! language ( ! text to be t ( ! nation to :i* ! milit>y =ce belongs4 ,! language ( ! text ( ! message ( secret ag5ts is1 h[ev]1 ano!r matt] &1 9 deal+ ) su* messages1 we %\ld use all available evid5ce1 bo? ext]nal & int]nal1 be=e decid+ f9ally on ! language us$4 ,:5ev] a frequ5cy table c be prep>$1 su* a table w give ! be/ evid5ce = ?is purpose4 ,all "w 9 enciph]+ & deciph]+ messages & 9 copy+ ciph]s %\ld be done ) capital lett]s4 ,!re is mu* less *ance ( error :5 work+ ) capitals &1 ) little practice1 x is j ab\t z fa/4 ,an additional safegu>d is to use black ink or p5cil = ! pla9 text & color$ ink or p5cil = ! ciph]4 ,a sep>ate color may be us$ = ! key :5 necess>y4 ,! foll[+ blank =m is sugge/$ z conv5i5t = keep+ a record ( a ciph] "u exam9ation4 ,x %\ld accompany ! ciph] ?r\gh ! exam9+ process & %\ld be fill$ 9 z ! facts are det]m9$4 ,?is record1 ! orig9al ciph] & all notes ( "w done dur+ ! exam9ation1 %\ld be fil$ toge!r :5 ! exam9ation is complet$1 :e!r ! ciph] has be5 solv$ or n4 ,x may be t o!r ciph]s solv$ lat] w give clues to ! solution ( su* unsolv$ ciph]s4 ,! fir/ column ( ?is blank %\ld be fill$ out f data furni%$ by ! (fic] obta9+ ! ciph] f ! enemy4 ,a g5]al ord]1 emphasiz+ ! importance ( promptly =w>d+ captur$ or int]cept$ ciph]s to an exam9+ (fice1 c\ld specify t a brief report embody+ ?is data %\ld be =w>d$ ) ea* ciph]4 ,! second column ( ! blank %\ld be fill$ out progressively z ! "w proce$s4 ,! (fice numb] %\ld be a s]ial "o1 ! fir/ ciph] exam9$ be+ ,no4 #a4 ,! date & h\r ( receipt at exam9+ (fice w be a *eck z to ! "t requir$ to transmit x f place ( capture4 ,! spaces ,f1 ,at1 ,to1 ,at1 ,date1 are = ! in=mation conc]n+ s5d] & addressee ( ! ciph] & are to be obta9$ f ! message4 ,9 case an op]ators' ciph] has be5 us$1 ^! p>ts ( ! message w h to be deciph]$ be=e ! blanks c be fill$ 94 ,intellig5ce ,section1 ,g5]al ,/aff #a/ ,field ,army ---------------------------------------- --------- ,place1 ,date ,record ( ,ciph] ,exam9ation ,?is ciph] obta9$ by ,(fice ,no4 ----------------------- ,receiv$ ------------- ----------- ---------------------------------- 7,date7 7,h\r7 ---------------------------------- ,f ----------------------------- at ------------------------------- ,at ------------------------------- on ---------------- -------------- ,to ------------------------------- 7date7 7h\r7 ,at ------------------------------- ,h[ be+ transmitt$ :5 obta9$4 7,und]score means us$ & ent] ,date ----------------------------- data on s5d+ & receiv+ /ations74 ,probable language ( text -------- ,s5d+ ,receiv+ ,transposition ---------- ,/ation ,/ation ------------------------ ,radio ,class ,telephone ,sub/itution ----------- ,telegraph ,buzz] ------------------------ ,helio ,lant]n ,case ----------------------------- ,flag ,cycli/ f to ,rem>ks3 ,foot ,mess5g] 11 11 ,mtd4 ,mess5g] 11 11 ,h[ obta9$4 7,und]score means us$74 ,captur$ be=e deliv]y ,solution complet$ --------- ------ to addressee4 ,captur$ aft] 7date7 7h\r7 deliv]y to addressee4 ,int]cept$1 n receiv$ by addressee4 ,copi$1 ,language ( text ------------------ b receiv$ by addressee4 ,key1 7if det]m9$7 -------------- ,rem>ks3 ----------------------------------- ,type ---------- ,file ,no4 ---------- ----------------------------------- ----------------------------------- ,exam9]4 ,! probable language ( ! text is assum$ f ! prec$+ data &1 if necess>y1 f int]nal evid5ce4 ,?us a ciph] f a ,mexican s\rce & n conta9+ ,k or ,w is probably 9 ,spani%4 ,! class & case are det]m9$ by ! rules laid d[n lat]4 ,! space = rem>ks is to p]mit notation ( any special features4 ,:5 ! solution is complet$1 ! date & h\r are not$1 ! language ( text & key 7if det]m9$7 are ent]$ & a type numb]1 to id5tify x ) o!r ciph]s prep>$ by ! same me?od 7b n necess>ily ! same key71 is giv5 to x4 ,! file numb] is = conv5i5ce 9 fil+ & 9 prep>ation ( a c>d index4 ,! process ( exam9ation 9 an (fice ) "o exam9]1 "o /5ograph] & "o cl]k1 might be z foll[s3 ,on receipt ( a captur$ ciph] ) accompany+ report1 ! /5ograph] makes f\r copies ( ! ciph] on ! typewrit]4 ,! cl]k & /5ograph] !n *eck ! "w4 ,! /5ograph] !n proce$s to fill out ! fir/ column & fir/ two l9es ( ! second column ( ! record blank f ! report ( ! captur+ (fic]1 keep+ ! orig9al ciph] & two copies ) ! record4 ,he may also fill out ! fir/ sev5 l9es ( ! second column1 if ?is data is on ! captur$ ciph] 9 pla9 text4 ,9 ! meantime ! cl]k is c\nt+ & sett+ d[n ! :ole numb] ( lett]s ( ! ciph] & ! occurr5ce ( ,,aei\1 ,,lnr/1 & ,,jkqxz1 :ile ! exam9+ (fic] is look+ ov] ! ciph] = possible recurr+ gr\ps ( lett]s & und]l9+ !m :5 f\nd4 ,?is "w be+ complet$1 ! exam9+ (fic] is 9 a position1 ord9>ily1 to decide on ! class ( ! ciph] & he may h f\nd some?+ 9 8 exam9ation :i* w lead him to ! case "u ! class4 ,! cl]k 9 ?is prelim9>y c\nt %\ld keep track ( ! total occurr5ce ( ea* ( ! fifte5 *eck lett]s & n ( ! ?ree gr\ps giv5 above4 ,?is takes a little long] b :5 done1 ! data = fifte5 lett]s ( ! alphabet = a frequ5cy table is complet$1 leav+ only elev5 o!r lett]s1 & 9 ,spani%1 b n9e1 to be c\nt$1 9 case x is necess>y to prep>e a frequ5cy table4 ,if ! exam9+ (fic] decides ! ciph] to be ( ! transposition class1 no fur!r "w ) frequ5cy tables is necess>y4 ,! cl]k %\ld proce$ to c\nt & set d[n ! numb] ( v[els 9 ea* l9e & column & ! exam9+ (fic] %\ld look = any occurr5ce ( ! lett] ,q & try to connect x ) ,u & ano!r v[el4 ,! /5ograph] may be set to "w putt+ ! ciph] into rectangles ( diff]5t dim5sions4 ,! cl]k's "w gives data = possible re>rangem5t1 = if ! v[els are mu* out ( proportion at any po9t1 !y mu/ be connect$ ) ! prop] proportion ( consonants z a fir/ /ep 9 re>rangem5t4 ,"w ) transposition ciph]s mu/ necess>ily include mu* ( ! fit & try me?od4 ,! details ( ?is "w are tak5 up lat]4 ,if a ciph] seems to be a sub/itution ciph]1 ! exam9+ (fic] %\ld look ov] ! frequ5cy ( occurr5ce ( ea* ( ! fifte5 lett]s c\nt$4 ,if "s lett]s 7x is ( no importance at pres5t :i* ones7 occur mu* m frequ5tly ?an o!rs & "s occur r>ely or n at all1 we may safely decide on ,case #d1 #e or #f & let ! cl]k proce$ to f9i% ! frequ5cy table = ! message4 ,on ! o!r h&1 if all ! fifte5 lett]s exam9$ occur ) some:]e ne> ! same frequ5cy--= example1 ! mo/ common lett] occurr+ n ov] ?ree or f\r times z (t5 z ! lea/ common lett]--we may at once elim9ate ! fir/ ?ree cases & let ! cl]k proce$ to exam9e ! ciph] = recurr+ pairs & gr\ps1 c\nt+ ! int]v5+ lett]s1 s t ! exam9+ (fic] may decide :e!r ,case #g1 or "s m complicat$ case1 %\ld be *os54 ,if some?+ m complicat$ ?an ,case #g has be5 us$ & o!r ciph]s are on h& await+ exam9ation1 ! ciph] %\ld g into ! unsolv$ file to be work$ on :5 o!r "w p]mits1 unless ! cont5ts ( ! ciph] are believ$ to be v important4 ,e opportunity %\ld be tak5 to clean up ! unsolv$ file &1 :5ev] a message is solv$1 ! me?ods %\ld be tri$1 if applicable1 to ev]y?+ rema9+ 9 ! file4 ,! fir/ few days or weeks aft] ! e/abli%m5t ( an exam9+ (fice w be ! mo/ try+ "t4 ,:5 solv$ ciph]s beg9 to pile up1 ! me?ods ( ! enemy w be m & m app>5t & x w (t5 be possible to det]m9e ! me?od f k ( ! "n ( ! s5d] & receiv]4 ,:5 a ciph] has be5 solv$1 ! solution %\ld be prep>$ 9 triplicate & giv5 ! s]ial numb] ( ! ciph]4 ,any p>ts :i* are n cle>1 ?r\gh errors 9 enciph]+ or 9 transmission1 %\ld be und]l9$ or o!rwise made conspicu\s1 s t ! head ( ! ,intellig5ce ,section may note !m &1 possibly1 f o!r s\rces1 supply ! defici5cy4 ,"o ( ! copies ( ! ciph] & report ( exam9ation1 ) a copy ( ! solution1 %\ld be turn$ ov] at once to ! head ( ! ,intellig5ce ,section or to ! ,*ief ( ,/aff4 ,! o!r copies ( ! solution %\ld be fil$ ) ! orig9al ciph]1 ! report ( exam9ation1 & all "w done on ! ciph]4 ,p]iodically1 say once a week or ev5 daily at ! beg9n+ ( active op]ations1 !re %\ld be an int]*ange betwe5 all exam9+ (fices ( solv$ messages involv+ new me?ods us$ by ! enemy4 ,all ! exam9+ (fices w ?us be kept 9 t\*4 ,x may also be possible to assign c]ta9 ho/ile radio /ations to ea* exam9+ (fice to prev5t duplication ( "w4 ,,*apt] ,,iv ,,classes ,,( ,,ciph]s ,!re are1 9 g5]al1 two classes ( ciph]s4 ,^! are ! transposition ciph] & ! sub/itution ciph]4 ,sub/itution ciph]s may be made up ( sub/itut$ lett]s1 num]als1 conv5tional signs or comb9ations ( all ?ree2 & fur!rmore1 = a s+le lett] ( ! orig9al text !re may be sub/itut$ a s+le lett]1 num]al or sign or two or m ( ea*1 or a :ole ^w or gr\p ( figures1 comb9ation ( conv5tional signs1 or comb9ations ( all ?ree ( ^! elem5ts4 ,?us sub/itution ciph]s may v>y f ^? ( extreme simplicity to ^? ^: complication defies any ord9>y me?od ( analysis & ^: solution requires ! possession ( long messages & mu* "t & /udy4 ,=tunately ! m difficult sub/itution ciph]s are r>ely us$ = milit>y purposes1 on acc\nt ( ! "t & c>e requir$ = enciph]+ & deciph]+4 ,transposition ciph]s are limit$ to ! *>act]s ( ! orig9al text4 ,^! *>act]s are re>rang$ s+ly1 accord+ to "s pr$et]m9$ me?od or key 7monolit]al transposition71 or :ole words are simil>ly re>rang$ 7r\te ciph]74 ,!re may also be a comb9ation ( transposition & sub/itution me?ods 9 enciph]+ a message b 9 ?is case x w fall into ! sub/itution class on fir/ det]m9ation & aft] solution z a sub/itution ciph] x mu/ be h&l$ z a transposition ciph]4 ,examples ( ?is case w be giv54 ,we may also f9d transposition or sub/itution me?ods appli$ to words tak5 f a code book1 or to numb]s :i* repres5t ^! words4 ,?us ciph] me?ods bl5d into code "w1 = a code is1 aft] all1 only a specializ$ sub/itution ciph]4 ,we c n[ lay d[n ! rules = det]m9+ :e!r any giv5 ciph] belongs to ! sub/itution class or to ! transposition class4 ,c\nt ! numb] ( lett]s 9 ! message1 ! numb] ( v[els1 ,,aei\1 ! numb] ( ! consonants1 ,,lnr/1 & ! numb] ( ! consonants1 ,,jkqxz4 ,if ! text is ,engli% & ! ciph] is a transposition ciph]1 ?is proportion w hold2 v[els ,,aei\ con/itute #dj ( ! :ole2 consonants ,,lnr/1 #cj & consonants ,,jkqxz1 #c4 ,if ! text be ,spani% ! proportions = a transposition ciph] w be3 v[els ,,aei\ #de1 consonants ,,lnr/1 #cj2 consonants ,,jkqxz1 #b4 ,if ^! proportions d n hold )9 #e1 "o way or ! o!r1 ! ciph] is c]ta9ly a sub/itution ciph]4 ,note1 h[ev]1 t (t5 ! end ( a message is fill$ ) lett]s l ,k1 ,x1 ,z to complete ciph] words & x is be/ to neglect ! la/ ^w or words 9 mak+ a c\nt4 ,also1 if ! ciph] be a long "o1 ?is det]m9ation c safely be made by tak+ #ajj or #bjj consecutive lett]s ( ! message1 ei!r f ! beg9n+ or1 if nulls at ! beg9n+ are suspect$1 f ! int]ior ( ! message4 ,! di/9ction betwe5 ! r\te ciph] 7transposition7 & ! sub/itution ciph] :]e :ole words are sub/itut$ = lett]s ( ! orig9al text1 mu/ be made on ! basis ( ! words actually us$4 ,x is bett] to consid] su* a message z a r\te ciph] :5 ! words us$ appe> to h "s consecutive mean+ be>+ on ! situation at h&4 ,a sub/itution ciph] ( ?is v>iety w\ld only be us$ = transmission ( a %ort message ( great importance & secrecy1 & !n ! *ances are t c]ta9 words correspond+ to ,a1 ,e1 ,n1 ,o & ,t w\ld appe> ) su* frequ5cy z to po9t at once to ! fact t a sub/itution ciph] 0 us$4 ,wat* ! initial or t]m9al lett]s 9 su* a ciph]2 !y may spell ! message4 ,9 g5]al1 ! det]m9ation ( class by proportion ( v[els1 common consonants & r>e consonants may be safely foll[$4 ,we w n[ proce$ to ! exam9ation ( ! m common v>ieties ( ea* class ( ciph]4 ,,*apt] ,v ,,exam9ation ,,( ,,transposition ,,ciph]s ,aft] hav+ decid$ t a ciph] belongs to ! transposition class1 x rema9s to decide on ! v>iety ( ciph] us$4 ,z1 by def9ition1 a transposition ciph] consi/s :olly ( *>act]s ( ! orig9al message1 re>rang$ accord+ to "s law1 we may1 9 g5]al1 say t su* a ciph] (f]s few] difficulties 9 solution ?an a sub/itution ciph]4 ,a transposition ciph] is l a picture puzzle2 ! p>ts are all !re & ! solution m]ely involves _! correct arrangem5t4 ,case #a4--;,geometrical ciph]s4 ,?is case includes all ciph]s 9 :i* a c]ta9 numb] ( ! *>act]s are *os5 s t !y w =m a squ>e or rectangle ( pr$et]m9$ dim5sions2 & !n ^! *>act]s are arrang$ accord+ to a geometrical design4 ,tak+ ! message3 ,a ,b ,c ,d ,e ,f ,g ,h ,i ,j ,k ,l ,m ,n ,o ,p ,q ,r ,s ,t ,u ,v ,w ,x ( tw5ty-f\r lett]s & assum+ a rectangle ( six lett]s horizontally1 & f\r lett]s v]tically1 we may h3 7a7 ,simple ,horizontal3 ,a ,b ,c ,d ,e ,f ,f ,e ,d ,c ,b ,a ,s ,t ,u ,v ,w ,x ,x ,w ,v ,u ,t ,s ,g ,h ,i ,j ,k ,l ,l ,k ,j ,i ,h ,g ,m ,n ,o ,p ,q ,r ,r ,q ,p ,o ,n ,m ,m ,n ,o ,p ,q ,r ,r ,q ,p ,o ,n ,m ,g ,h ,i ,j ,k ,l ,l ,k ,j ,i ,h ,g ,s ,t ,u ,v ,w ,x ,x ,w ,v ,u ,t ,s ,a ,b ,c ,d ,e ,f ,f ,e ,d ,c ,b ,a 7b7 ,simple ,v]tical3 ,a ,e ,i ,m ,q ,u ,d ,h ,l ,p ,t ,x ,u ,q ,m ,i ,e ,a ,x ,t ,p ,l ,h ,d ,b ,f ,j ,n ,r ,v ,c ,g ,k ,o ,s ,w ,v ,r ,n ,j ,f ,b ,w ,s ,o ,k ,g ,c ,c ,g ,k ,o ,s ,w ,b ,f ,j ,n ,r ,v ,w ,s ,o ,k ,g ,c ,v ,r ,n ,j ,f ,b ,d ,h ,l ,p ,t ,x ,a ,e ,i ,m ,q ,u ,x ,t ,p ,l ,h ,d ,u ,q ,m ,i ,e ,a 7c7 ,alt]nate ,horizontal3 ,a ,b ,c ,d ,e ,f ,f ,e ,d ,c ,b ,a ,x ,w ,v ,u ,t ,s ,s ,t ,u ,v ,w ,x ,l ,k ,j ,i ,h ,g ,g ,h ,i ,j ,k ,l ,m ,n ,o ,p ,q ,r ,r ,q ,p ,o ,n ,m ,m ,n ,o ,p ,q ,r ,r ,q ,p ,o ,n ,m ,l ,k ,j ,i ,h ,g ,g ,h ,i ,j ,k ,l ,x ,w ,v ,u ,t ,s ,s ,t ,u ,v ,w ,x ,a ,b ,c ,d ,e ,f ,f ,e ,d ,c ,b ,a 7d7 ,alt]nate ,v]tical3 ,a ,h ,i ,p ,q ,x ,d ,e ,l ,m ,t ,u ,x ,q ,p ,i ,h ,a ,u ,t ,m ,l ,e ,d ,b ,g ,j ,o ,r ,w ,c ,f ,k ,n ,s ,v ,w ,r ,o ,j ,g ,b ,v ,s ,n ,k ,f ,c ,c ,f ,k ,n ,s ,v ,b ,g ,j ,o ,r ,w ,v ,s ,n ,k ,f ,c ,w ,r ,o ,j ,g ,b ,d ,e ,l ,m ,t ,u ,a ,h ,i ,p ,q ,x ,u ,t ,m ,l ,e ,d ,x ,q ,p ,i ,h ,a 7e7 ,simple ,diagonal3 ,a ,b ,d ,g ,k ,o ,g ,k ,o ,s ,v ,x ,o ,k ,g ,d ,b ,a ,x ,v ,s ,o ,k ,g ,c ,e ,h ,l ,p ,s ,d ,h ,l ,p ,t ,w ,s ,p ,l ,h ,e ,c ,w ,t ,p ,l ,h ,d ,f ,i ,m ,q ,t ,v ,b ,e ,i ,m ,q ,u ,v ,t ,q ,m ,i ,f ,u ,q ,m ,i ,e ,b ,j ,n ,r ,u ,w ,x ,a ,c ,f ,j ,n ,r ,x ,w ,u ,r ,n ,j ,r ,n ,j ,f ,c ,a ,a ,c ,f ,j ,n ,r ,j ,n ,r ,u ,w ,x ,r ,n ,j ,f ,c ,a ,x ,w ,u ,r ,n ,j ,b ,e ,i ,m ,q ,u ,f ,i ,m ,q ,t ,v ,u ,q ,m ,i ,e ,b ,v ,t ,q ,m ,i ,f ,d ,h ,l ,p ,t ,w ,c ,e ,h ,l ,p ,s ,w ,t ,p ,l ,h ,d ,s ,p ,l ,h ,e ,c ,g ,k ,o ,s ,v ,x ,a ,b ,d ,g ,k ,o ,x ,v ,s ,o ,k ,g ,o ,k ,g ,d ,b ,a 7f7 ,alt]nate ,diagonal3 ,a ,b ,f ,g ,n ,o ,g ,n ,o ,u ,v ,x ,o ,n ,g ,f ,b ,a ,x ,v ,u ,o ,n ,g ,c ,e ,h ,m ,p ,u ,f ,h ,m ,p ,t ,w ,u ,p ,m ,h ,e ,c ,w ,t ,p ,m ,h ,f ,d ,i ,l ,q ,t ,v ,b ,e ,i ,l ,q ,s ,v ,t ,q ,l ,i ,d ,s ,q ,l ,i ,e ,b ,j ,k ,r ,s ,w ,x ,a ,c ,d ,j ,k ,r ,x ,w ,s ,r ,k ,j ,r ,k ,j ,d ,c ,a ,a ,c ,d ,j ,k ,r ,j ,k ,r ,s ,w ,x ,r ,k ,j ,d ,c ,a ,x ,w ,s ,r ,k ,j ,b ,e ,i ,l ,q ,s ,d ,i ,l ,q ,t ,v ,s ,q ,l ,i ,e ,b ,v ,t ,q ,l ,i ,d ,f ,h ,m ,p ,t ,w ,c ,e ,h ,m ,p ,u ,w ,t ,p ,m ,h ,f ,u ,p ,m ,h ,e ,c ,g ,n ,o ,u ,v ,x ,a ,b ,f ,g ,n ,o ,x ,v ,u ,o ,n ,g ,o ,n ,g ,f ,b ,a 7g7 ,spiral1 clockwise3 ,a ,b ,c ,d ,e ,f ,l ,m ,n ,o ,p ,a ,i ,j ,k ,l ,m ,n ,d ,e ,f ,g ,h ,i ,p ,q ,r ,s ,t ,g ,k ,v ,w ,x ,q ,b ,h ,u ,v ,w ,x ,o ,c ,r ,s ,t ,u ,j ,o ,x ,w ,v ,u ,h ,j ,u ,t ,s ,r ,c ,g ,t ,s ,r ,q ,p ,b ,q ,x ,w ,v ,k ,n ,m ,l ,k ,j ,i ,i ,h ,g ,f ,e ,d ,f ,e ,d ,c ,b ,a ,a ,p ,o ,n ,m ,l 7h7 ,spiral1 c\nt] clockwise3 ,a ,p ,o ,n ,m ,l ,n ,m ,l ,k ,j ,i ,i ,h ,g ,f ,e ,d ,f ,e ,d ,c ,b ,a ,b ,q ,x ,w ,v ,k ,o ,x ,w ,v ,u ,h ,j ,u ,t ,s ,r ,c ,g ,t ,s ,r ,q ,p ,c ,r ,s ,t ,u ,j ,p ,q ,r ,s ,t ,g ,k ,v ,w ,x ,q ,b ,h ,u ,v ,w ,x ,o ,d ,e ,f ,g ,h ,i ,a ,b ,c ,d ,e ,f ,l ,m ,n ,o ,p ,a ,i ,j ,k ,l ,m ,n ,x is simply a matt] ( inspection to read a message 9 a ciph] ( ?is type1 once ! dim5sions ( ! rectangles h be5 det]m9$4 ,we place ! :ole or a portion ( ! message 9 su* rectangles & read horizontally1 v]tically & diagonally =w>d & backw>d4 ,p>ts ( words w at once be app>5t & ! :ole message is soon deciph]$4 ,two examples w %[ ! process4 ,message ,,ilvgioiaeitsrnmanhmng ,?is message conta9s eight v[els or #ch out ( tw5ty-"o lett]s1 & ! lett]s ,,lnr/ occur #g times or #cc1 ! lett]s ,,xqjkz n appe>+4 ,x is !re=e a transposition ciph]4 ,tw5ty-"o lett]s imm$iately sugge/ sev5 columns ( ?ree lett]s ea* or ?ree columns ( sev5 lett]s ea*4 ,try+ ! =m] we h3 ,i ,l ,v ,g ,i ,o ,i ,a ,e ,i ,t ,s ,r ,n ,m ,a ,n ,h ,m ,n ,g & read+ d[n ea* column 9 succession 7,case #a-;b7 reveals ! message to be ,i am leav+ ?is morn+4 ,message ,m ,s ,i ,b ,r ,o ,r ,s ,e ,e ,v ,u ,e ,e ,m ,c ,o ,r ,e ,r ,e ,l ,i ,d ,e ,t ,o ,e ,p ,q ,e ,n ,r ,e ,r ,n ,s ,e ,r ,y ,e ,c ,o ,l ,l ,e ,r ,e ,u ,s ,p ,l ,u ,r ,c ,e ,l ,o ,a ,j ,a ,e ,h ,u ,h ,p ,f ,a ,s ,o ,n ,n ,o ,a ,a ,e ,p ,i ,u ,a ,p ,p ,e ,a ,c ,u ,q ,a ,r ,u ,o ,p ,o ,e ,i ,i ,r ,r ,m ,i ,a ,f ,d ,a ,a ,r ,q ,u ,b ,o ,z ,a ,e ,g ,e ,r ,s ,f ,s ,x ,!re are #abj lett]s 9 ?is message ) #eg v[els or #dg v[els1 & ! lett]s ,,lnr/ occur #ca times or #bf ( ! :ole4 ,non-occurr5ce ( ,k & ,w & v[el proportion leads u to ! assumption t x is a transposition ciph] ( a ,spani% text4 ,! factors ( #abj are #e #c #b #b #b4 ,we may !n h "o rectangle ( #d #cj or "o ( #e #bd or two ( #e #ab1 or ?ree ( #e #h1 or f\r ( #e #f1 or five ( #c #h1 or t5 ( #c #d1 or tw5ty ( #c #b4 ,! message be+ 9 a rectangle ( #d #cj1 we c inspect x z x /&s & ?is is cle>ly n ! arrangem5t if x be a geometrical transposition ciph] at all4 ,x is be/ h[ev] to try ! l>ge/ possible rectangles fir/ s we w put x 9 ! =m #e #bd1 ?us3 ,m ,s ,i ,b ,r ,o ,r ,s ,e ,e ,v ,u ,e ,e ,m ,c ,o ,r ,e ,r ,e ,l ,i ,d ,e ,t ,o ,e ,p ,q ,e ,n ,r ,e ,r ,n ,s ,e ,r ,y ,e ,c ,o ,l ,l ,e ,r ,e ,u ,s ,p ,l ,u ,r ,c ,e ,l ,o ,a ,j ,a ,e ,h ,u ,h ,p ,f ,a ,s ,o ,n ,n ,o ,a ,a ,e ,p ,i ,u ,a ,p ,p ,e ,a ,c ,u ,q ,a ,r ,u ,o ,p ,o ,e ,i ,i ,r ,r ,m ,i ,a ,f ,d ,a ,a ,r ,q ,u ,b ,o ,z ,a ,e ,g ,e ,r ,s ,f ,s ,x ,"h an inspection %[s ?is to be ,case #a-;f1 alt]nate diagonal1 & ! text to be ,,me ,,situo ,,sobre ,,p>ral ,,porque ,,me ,,pres5cia ,,fue ,,revelada ,,por ,u2 "h ! s5se breaks b note t ,u is ! twelf? lett] ( ! l9e & cont9ue z if ! rectangle 7 #e #ab & we h ,,na ,,p>eja ,,qu4 ,n[ inspect ! second rectangle ( #e #ab 9 ! same way & ! s5se cont9ues ,e ,,se ,,me ,,ac]co ,y ,,hubo ,,que ,,re*az> ,,por ,,el ,,fuego ,,alli ,,esr]o ,,ord5es ,,f9isx4 ,! practical way ( exam9+ a ciph] ( ?is type is to h sev]al m5 prep>e rectangles ( diff]5t dim5sions1 us+ ! lett]s ( ! ciph] 9 ! ord] receiv$4 ,! rectangles c be inspect$ v rapidly :5 once prep>$4 ,note t ! dim5sions ( any rectangle w r>ely be su* z to conta9 m ?an fifty lett]s1 on acc\nt ( ! necessity ( fill+ up a rectangle ) nulls if ! numb] ( lett]s ( ! message is j a little great] ?an a multiple ( ! rectangle4 ,also l>ge rectangles give1 = all b ! diagonal me?od1 :ole words 9 a l9e or column & ^! are easily not$4 ,! foll[+ ciph]s come "u ,case #a3 ,case #a-;i4--,! rail f5ce ciph]1 useful z an op]ators' ciph] b p]mits ( no v>iation & is !re=e read almo/ z easily z /raight text :5 ! me?od is kn[n4 ,! message3 ,,ho/ile ,,cavalry ,,has ,,retir$ is writt53 ,o ,t ,l ,c ,v ,l ,y ,a ,r ,t ,r ,d ,h ,s ,i ,e ,a ,a ,r ,h ,s ,e ,i ,e & is s5t3 ,,otlcv ,,ly>t ,,rdhsi ,,ea>h ,,seiex ,case #a-;j4 ,message ,s ,s ,o ,h ,s ,t ,p ,f ,o ,r ,i ,e ,e ,a ,e ,t ,q ,n ,e ,t ,f ,a ,i ,x ,e ,g ,l ,f ,d ,r ,a ,u ,l ,r ,n ,o ,s ,r ,x ,l ,h ,a ,t ,r ,o ,to solve ?is ciph]1 read d[n ! columns 9 ?is ord] #h1 #a1 #ae1 #b1 #ad1 #c1 #ac1 #d1 #ab1 etc4 ,a v>iation is to arrange ! ciph] s ! columns are read upw>ds4 ,ano!r is to arrange ! ciph]s s ! columns are read alt]nately upw>d & d[nw>d4 ,! factors ( ! numb] ( lett]s 9 ?is case give ! %ape ( ! rectangle z usual4 ,x w be se5 t !re are a great numb] ( possible transposition ciph]s t come "u ,case #a b practically all ( !m are useless f a milit>y /&po9t because !y d n dep5d on a key :i* c be readily & frequ5tly *ang$4 ,h[ev] su* ciph]s con/antly crop up 9 ciph] exam9ation1 be+ us$ = special communication betwe5 p>ties :o consid] ! regul> milit>y ciph]s too complicat$4 ,?us "s ( ^! exp$i5ts h be5 us$4 ,rev]s$ ,writ+4--7,special case ( ,case #a-;a74 ,,leav+ ,,tonight is enciph]$ ,,?g9ot ,,gnivael or x may be rev]s$ by words1 ?us ,,gnivael ,,?g9ot or by gr\ps ( five lett]s1 ?us ,,ivael ,,notgn ,,x?gi4 ,v]tical ,writ+4--7,special case ( ,case #a-;b74 ,same message is enciph]$1 ,,lt ,,eo ,,an ,,vi & is s5t1 ,,lteoa ,,nviig ,,nhgtx4 ,,ig ,,nh ,,gt ,case #b4--,?is case includes all transposition ciph]s 9 :i* l9es & columns ( ! text are re>rang$ accord+ to "s key ^w or key numb]4 ,!re are _m v>ieties ( ?is case b _! solution usually is arriv$ at ?r\gh ! me?ods sugge/$ = ,case #a1 t is1 arrangem5t into appropriate rectangles & exam9ation ( l9es & columns = words or syllables4 ,re>rangem5t ( columns or l9es foll[s until ! solution is complet$4 ,case #b-;a4 ,message ,,hiigf ,,tnghi ,,ntcvn ,,ieiot ,,cyify ,,lhaea ,,esnba ,,eee5 ,,rwgbn ,,ydelr ,,oaesg ,,rnebo ,,vnlda ,,icaoa ,,lcndt ,,irgva ,,cdoie ,,s]ec ,,dvpei ,,afifl ,,r9eh ,,ett ,!re are #ajh lett]s 9 ?is message & exam9ation %[s x to be a transposition ciph]1 ,engli% text4 ,! numb] ( lett]s1 #ajh1 imm$iately sugge/s a rectangle ( #ab #i or #i #ab lett]s4 ,put into ?is =m we h3 ,v[els ,v[els ,h ,i ,i ,g ,f ,t ,n ,g ,h ,i ,n ,t #c ,h ,i ,i ,g ,f ,t ,n ,g ,h #b ,c ,v ,n ,i ,e ,i ,o ,t ,c ,y ,i ,f #e ,i ,n ,t ,c ,v ,n ,i ,e ,i #d ,y ,l ,h ,a ,e ,a ,e ,s ,n ,b ,a ,e #f ,o ,t ,c ,y ,i ,f ,y ,l ,h #b ,e ,e ,e ,n ,r ,w ,g ,b ,n ,y ,d ,e #d ,a ,e ,a ,e ,s ,n ,b ,a ,e #f ,l ,r ,o ,a ,e ,s ,g ,r ,n ,e ,b ,o #e ,e ,e ,e ,n ,r ,w ,g ,b ,n #c ,v ,n ,l ,d ,a ,i ,c ,a ,o ,a ,l ,c #e ,y ,d ,e ,l ,r ,o ,a ,e ,s #d ,n ,d ,t ,i ,r ,g ,v ,a ,c ,d ,o ,i #d ,g ,r ,n ,e ,b ,o ,v ,n ,l #b ,e ,s ,e ,r ,e ,c ,d ,v ,p ,e ,i ,a #f ,d ,a ,i ,c ,a ,o ,a ,l ,c #e ,f ,i ,f ,l ,r ,i ,n ,e ,h ,e ,t ,t #d ,n ,d ,t ,i ,r ,g ,v ,a ,c #b ,d ,o ,i ,e ,s ,e ,r ,e ,c #e ,d ,v ,p ,e ,i ,a ,f ,i ,f #d ,l ,r ,i ,n ,e ,h ,e ,t ,t #c ,! v[el c\nt ( ! l9es %[s ! fir/ arrangem5t to be ! m likely4 ,we w n[ numb] ! columns & try pair+ (f c]ta9 ones :i* 9 no l9e w\ld give impossible comb9ations ( lett]s4 #a #b #c #d #e #f #g #h #i #aj #aa #ab ,h ,i ,i ,g ,f ,t ,n ,g ,h ,i ,n ,t ,c ,v ,n ,i ,e ,i ,o ,t ,c ,y ,i ,f ,y ,l ,h ,a ,e ,a ,e ,s ,n ,b ,a ,e ,e ,e ,e ,n ,r ,w ,g ,b ,n ,y ,d ,e ,l ,r ,o ,a ,e ,s ,g ,r ,n ,e ,b ,o ,v ,n ,l ,d ,a ,i ,c ,a ,o ,a ,l ,c ,n ,d ,t ,i ,r ,g ,v ,a ,c ,d ,o ,i ,e ,s ,e ,r ,e ,c ,d ,v ,p ,e ,i ,a ,f ,i ,f ,l ,r ,i ,n ,e ,h ,e ,t ,t ,^! comb9ations appe> among o!rs3 #a #f #b #d #e #b ,h ,t ,i ,g ,f ,i ,c ,i ,v ,i ,e ,v ,y ,a ,l ,a ,e ,l ,e ,w ,e ,n ,r ,e ,l ,s ,r ,a ,e ,r ,v ,i ,n ,d ,a ,n ,n ,g ,d ,i ,r ,d ,e ,c ,s ,r ,e ,s ,f ,i ,i ,l ,r ,i ,! ^w ,,fight />es at u f ! fir/ l9e2 let u arrange ! columns ?us3 #e #b #d #a #f #c ,f ,i ,g ,h ,t ,i ,e ,v ,i ,c ,i ,n ,e ,l ,a ,y ,a ,h ,r ,e ,n ,e ,w ,e ,e ,r ,a ,l ,s ,o ,a ,n ,d ,v ,i ,l ,r ,d ,i ,n ,g ,t ,e ,s ,r ,e ,c ,e ,r ,i ,l ,f ,i ,f ,we h ! words ,,fighti7,,ng71 ,,vic97,,ity71 ,,r5ewe7,d71 ,,&vil7,,la71 ,,rd+t7,o71 ,,rece7,,iv$74 ,) ?is to g on1 we mu/ *oose column #aa z ! next "o & !n 9 ord]1 columns #h1 #aj1 #g1 #ab1 #i4 ,b note t ! ord] #aa1 #h1 #aj1 #g1 #ab1 #i1 is ! same z ! ord] #e1 #b1 #d1 #a1 #f1 #c4 ,! message 0 writt5 9 twelve columns & ! columns h be5 transpos$ 9 t ord]4 ,we may1 al?\gh x is entirely unnecess>y1 speculate on ! key ^w us$4 ,x 0 probably ,m ,e ,x ,i ,c ,o #d #b #f #c #a #e mean+ t ! #d? column ( ! pla9 text 0 transf]r$ 9 enciph]+ s x became our #a/1 ! #b;d column rema9$ ! #b;d2 ! #f? column became our #c;d1 etc4 ,actually1 ?is ciph] 0 solv$ because ! ^w ,,villa 0 suspect$ & all ! necess>y lett]s 7 f\nd 9 l9e six ( ! arrangem5t 9 twelve columns4 ,! ord] #a1 #f1 #c1 #aa1 #h 0 tri$ & gave ?is result4 #a #f #c #aa #h ,h ,t ,i ,n ,g ,c ,i ,n ,i ,t ,y ,a ,h ,a ,s ,e ,w ,e ,d ,b ,l ,s ,o ,b ,r ,v ,i ,l ,l ,a ,n ,g ,t ,o ,a ,e ,c ,e ,i ,v ,f ,i ,f ,t ,e ,! rema9d] ( ! solution foll[$ ! l9es already laid d[n &1 naturally1 (f]$ no difficulties1 9 view ( ! l>ge numb] ( connect$ syllables available4 ,case #b-;b4 ,message ,,slc( ,,weetn ,,ebrdo ,,orvym ,,ff$i ,,nmtec ,,roi> ,,p]ho ,,esets ,,rfbhl ,,t5ah ,,optau ,,somtl ,,rtett ,,ascbh ,,niodc ,,r55 ,,aaprd ,,lacye ,,eciie ,,sgufn ,?is is a transposition ciph]1 ,engli% text1 & conta9s #aje lett]s4 ,! factors ( #aje are #e #c #g s t we mu/ inve/igate ! foll[+ rectangles2 #e #ba1 #ae #g1 ?ree ( #e #g1 five ( #c #g & sev5 ( #e #c4 #ba #e ,v[els ,s ,l ,c ,o ,f ,w ,e ,e ,t ,n ,e ,b ,r ,d ,o ,o ,r ,v ,y ,m ,f #f ,f ,e ,d ,i ,n ,m ,t ,e ,c ,r ,o ,i ,a ,r ,p ,e ,r ,h ,o ,e ,s #i ,e ,t ,s ,r ,f ,b ,h ,l ,t ,e ,n ,a ,h ,o ,p ,t ,a ,u ,s ,o ,m #g ,t ,l ,r ,t ,e ,t ,t ,a ,s ,c ,b ,h ,n ,i ,o ,d ,c ,r ,e ,n ,e #f ,n ,a ,a ,p ,r ,d ,l ,a ,c ,y ,e ,e ,c ,i ,i ,e ,s ,g ,u ,f ,n #i ,v[els #a #b #a #b #a #j #a #d #j #a #c #c #a #c #c #c #a #a #c #b #a ,! v[el c\nt ( ! columns ( ! rectangle #e #ba is v satisfactory4 ,let u consid] x z ?ree blocks ( #e #g ea*1 s9ce we mu/ d ?is ultimately1 & make a v[el c\nt ( columns = ^! blocks4 #e #ba ,v[els ,s ,l ,c ,o ,f #a ,w ,e ,e ,t ,n #b ,e ,b ,r ,d ,o #b ,o ,r ,v ,y ,m #a ,f ,f ,e ,d ,i #b ,n ,m ,t ,e ,c #a ,r ,o ,i ,a ,r #c ,p ,e ,r ,h ,o #b ,e ,s ,e ,t ,s #b ,r ,f ,b ,h ,l #j ,t ,e ,n ,a ,h #b ,o ,p ,t ,a ,u #c ,s ,o ,m ,t ,l #a ,r ,t ,e ,t ,t #a ,a ,s ,c ,b ,h #a ,n ,i ,o ,d ,c #b ,r ,e ,n ,e ,n #b ,a ,a ,p ,r ,d #b ,l ,a ,c ,y ,e #b ,e ,c ,i ,i ,e #d ,s ,g ,u ,f ,n #a ,v[els #g #i #h #g #f ,column #a #b #c #d #e ,v[els1 #a/ block #b #b #c #b #b ,v[els1 #b;d block #b #c #b #b #b ,v[els1 #c;d block #c #d #c #b #b ,?is is also excell5t1 s we w try ?ree blocks #e #g & see if re>rangem5t ( horizontal l9es w give results read+ ! columns v]tically4 #a ,s ,l ,c ,o ,f ,p ,e ,r ,h ,o ,a ,s ,c ,b ,h #b ,w ,e ,e ,t ,n ,e ,s ,e ,t ,s ,n ,i ,o ,d ,c #c ,e ,b ,r ,d ,o ,r ,f ,b ,h ,l ,r ,e ,n ,e ,n #d ,o ,r ,v ,y ,m ,t ,e ,n ,a ,h ,a ,a ,p ,r ,d #e ,f ,f ,e ,d ,i ,o ,p ,t ,a ,u ,l ,a ,c ,y ,e #f ,n ,m ,t ,e ,c ,s ,o ,m ,t ,l ,e ,c ,i ,i ,e #g ,r ,o ,i ,a ,r ,r ,t ,e ,t ,t ,s ,g ,u ,f ,n ,among o!r comb9ations are3 #c ,e ,b ,r ,d ,o ,r ,f ,b ,h ,l ,r ,e ,n ,e ,n #b ,w ,e ,e ,t ,n ,e ,s ,e ,t ,s ,n ,i ,o ,d ,c #a ,s ,l ,c ,o ,f ,p ,e ,r ,h ,o ,a ,s ,c ,b ,h #e ,f ,f ,e ,d ,i ,o ,p ,t ,a ,u ,l ,a ,c ,y ,e #g ,r ,o ,i ,a ,r ,r ,t ,e ,t ,t ,s ,g ,u ,f ,n ,! addition ( l9e #f above l9e #c & l9e #d bel[ l9e #g w complete ?is ciph]4 ,! successive columns %\ld be read d[nw>d4 ,case #b-;c4 ,9 ?is case1 bo? l9es & columns are re>rang$ by means ( a key ^w or key words4 ,! me?od ( solution is ! same z ,case #b-;a & #b-;b except t ! l9es mu/ be re>rang$ aft] ! columns h be5 correctly arrang$1 or 9 "s cases1 vice v]sa4 ,?is ciph] is n infrequ5tly met ) because x seems to (f] safety by use ( two key words & by ! great b only app>5t complexity ( ! me?od4 ,message ,,wvgae ,,eg5l ,,tftoh ,,teief ,,rbtse ,,in5g ,,onwrm ,,gxixn ,,goitn ,,romro ,,espal ,,hneac ,,udnnh ,,d]me ,?is is a transposition ciph]1 ,engli% text & ! numb] ( lett]s1 #gj1 leads u to try rectangles ( #aj #g & #g #aj4 ,v[els ,v[els ,w ,v ,g ,a ,e ,e ,g ,e ,n ,l #d ,w ,v ,g ,a ,e ,e ,g #c ,t ,f ,t ,o ,h ,t ,e ,i ,e ,f #c ,e ,n ,l ,t ,f ,t ,o #b ,r ,b ,t ,s ,e ,i ,n ,e ,n ,g #c ,h ,t ,e ,i ,e ,f ,r #c ,o ,n ,w ,r ,m ,g ,x ,i ,x ,n #b ,b ,t ,s ,e ,i ,n ,e #c ,g ,o ,i ,t ,n ,r ,o ,m ,r ,o #d ,n ,g ,o ,n ,w ,r ,m #a ,e ,s ,p ,a ,l ,h ,n ,e ,a ,c #d ,g ,x ,i ,x ,n ,g ,o #b ,u ,d ,n ,n ,h ,d ,e ,r ,m ,e #c ,i ,t ,n ,r ,o ,m ,r #b ,o ,e ,s ,p ,a ,l ,h #c ,n ,e ,a ,c ,u ,d ,n #c ,n ,h ,d ,e ,r ,m ,e #b ,! fir/ =m looks ! m likely f ! v[el c\nt4 ,we proce$ to numb] ! columns & l9es & try re>rangem5t ( columns s z to obta9 possible lett] comb9ations f e l9e4 #a #b #c #d #e #f #g #h #i #aj #a ,w ,v ,g ,a ,e ,e ,g ,e ,n ,l #b ,t ,f ,t ,o ,h ,t ,e ,i ,e ,f #c ,r ,b ,t ,s ,e ,i ,n ,e ,n ,g #d ,o ,n ,w ,r ,m ,g ,x ,i ,x ,n #e ,g ,o ,i ,t ,n ,r ,o ,m ,r ,o #f ,e ,s ,p ,a ,l ,h ,n ,e ,a ,c #g ,u ,d ,n ,n ,h ,d ,e ,r ,m ,e ,among o!r comb9ations we h ^!3 #c #e #a #d #b #h #aj #f #i #g #a ,g ,e ,w ,a ,v ,e ,l ,e ,n ,g #b ,t ,h ,t ,o ,f ,i ,f ,t ,e ,e #c ,t ,e ,r ,s ,b ,e ,g ,i ,n ,n #d ,w ,m ,o ,r ,n ,i ,n ,g ,x ,x #e ,i ,n ,g ,t ,o ,m ,o ,r ,r ,o #f ,p ,l ,e ,a ,s ,e ,c ,h ,a ,n #g ,n ,h ,u ,n ,d ,r ,e ,d ,m ,e ,a v casual inspection ( ! l9es %[s t !y %\ld be re>rang$ 9 ord] #f1 #a1 #b1 #g1 #c1 #e1 #d1 z foll[s3 #c #e #a #d #b #h #aj #f #i #g #f ,p ,l ,e ,a ,s ,e ,c ,h ,a ,n #a ,g ,e ,w ,a ,v ,e ,l ,e ,n ,g #b ,t ,h ,t ,o ,f ,i ,f ,t ,e ,e #g ,n ,h ,u ,n ,d ,r ,e ,d ,m ,e #c ,t ,e ,r ,s ,b ,e ,g ,i ,n ,n #e ,i ,n ,g ,t ,o ,m ,o ,r ,r ,o #d ,w ,m ,o ,r ,n ,i ,n ,g ,x ,x ,al?\gh ( no p>ticul> importance1 x may be /at$ t ! column key 9 ?is case 0 ,,gr& & ! l9e key 0 ,,c5tral1 bo? us$ z 9 enciph]+ ,case #b-;a4 ,case #c4 ,r\te ciph]s4 ,9 ?is case1 :ole words ( ! message are transpos$ accord+ to "s ( ! me?ods ( ,case #a or #b or _! equival5ts4 ,! r\te ciph] is little us$ at pres5t4 ,its developm5t & use dur+ ! ,civil ,w> 0 caus$ by ! inability ( ! telegraph]s ( t day to h&le regul> ciph] matt] correctly & rapidly4 ,x 01 ev5 9 ^? days1 frankly only a delay+ ciph] &1 to be ( any value1 _h to be fill$ ) mean+less words to conceal ! message prop]4 ,an example f ! ,signal ,book w suffice to %[ ! g5]al "* ( r\te ciph]s4 ,to "o famili> ) monolit]al transposition ciph]s1 ev5 ! be/ ( r\te ciph]s (f]s b little difficulty4 ,to enciph] ! message ',,move ,,daylight4 ,,enemy ,,approa*+ ,,f ,,nor?4 ,,prison]s ,,say ,,/r5g? ,,"o ,,hundr$ ,,?\s&4 ,,meet ,,him ,,z ,,plann$4' arrange z foll[s3 ,,move ,,/r5g? ,,plann$ ,,say ,,daylight ,,"o ,,z ,,prison]s ,,enemy ,,hundr$ ,,him ,,nor? ,,approa*+ ,,?\s& ,,meet ,,f ,"h ! r\te is d[n ! fir/ column1 up ! f\r?1 d[n ! second & up ! ?ird4 ,?is ciph] 0 (t5 complicat$ by ! introduction ( nulls = e fif? ^w4 ,?us ! above message might be s5t3 ,,move ,,/r5g? ,,plann$ ,,say ,,nev] ,,daylight ,,"o ,,z ,,prison]s ,,leav+ ,,enemy ,,hundr$ ,,him ,,nor? ,,un*ang$ ,,approa*+ ,,?\s& ,,meet ,,f ,,come4 ,! words 9 italics are nulls & n a "p ( ! message & ! receiv] elim9ates !m be=e arrang+ 8 message 9 columns to get ! s5se ( x4 ,z an additional complication1 x 0 cu/om>y = ea* correspond5t to h a diction>y or code 9 :i* ! names ( all prom95t g5]als & places & _m ( ! prom95t v]bs1--z to m>*1 to sail1 to encamp1 to attack1 to retreat1--7 repres5t$ by o!r words4 ,a r\te ciph] us+ ! code words ( ! ,w> ,dep>tm5t code might h "s advantages ov] ! me?od ( enciph]+ code messages z prescrib$ 9 t ,code4 ,g5]al ,rem>ks on ,transposition ,ciph]s ,x is ! cons5sus ( op9ion ( exp]ts t ! transposition ciph] is n ! be/ "o = milit>y purposes4 ,x does n fulfill ! fir/1 second1 & ?ird ( ,k]ckh(fs' requirem5ts z to indeciph]ability1 safety :5 app>atus & me?od fall into ! h&s ( ! enemy1 & dep5dability on a readily *angeable key ^w4 ,h[ev]1 transposition ciph]s are (t5 enc\nt]$4 ,!y are favorites ) ^? :o f9d ! sub/itution ciph]s too difficult & too t$i\s to h&le & :o believe t _! transposition me?ods are ei!r absolutely indeciph]able or suffici5tly s = ! purpose ( conceal+ ! text ( a message = ! "t be+4 ,!y seem to be p>ticul>ly popul> ) secret ag5ts & spies1 presumably because special app>atus is r>ely necess>y 9 enciph]+ & deciph]+4 ,al?\gh ! numb] ( transposition me?ods is legion1 !y c practically all be consid]$ "u "o ( ! ?ree cases already discuss$4 ,x is surpris+ h[ (t5 transposition ciph]s prep>$ by complicat$ rules1 w1 on analysis1 be se5 to be v simple4 ,to be successful 9 solv+ transposition ciph]s1 "o %\ld con/antly practice read+ backw>d & up & d[n columns1 s t ! common comb9ations ( lett]s are z quickly id5tifi$ :5 se5 ?us z :5 enc\nt]$ 9 /raight text4 ,comb9ations l ,,eht1 ,,lliw1 ,,r(1 ,,dna1 etc41 %\ld be appreciat$ imm$iately z common words writt5 backw>d4 ,a /udy ( ! table ( frequ5cy ( digraphs or pairs is also excell5t practice & su* a table %\ld be at h& :5 a transposition ciph] is "u consid]ation4 ,x assi/s greatly if ,case #b be enc\nt]$ & is ( consid]able use 9 solv+ ,case #a4 ,! solution ( r\te ciph]s is necess>ily "o ( try & fit1 ) ! k t su* ciph]s usually are read up & d[n columns4 ,x is n believ$ t r\te ciph]s w (t5 be met ) at ! pres5t day4 ,,*apt] ,,vi ,,exam9ation ,,( ,,sub/itution ,,ciph]s ,:5 an unkn[n ciph] has be5 put into ! sub/itution class by ! me?ods already describ$ we may proce$ to decide on ! v>iety ( sub/itution ciph] :i* has be5 us$4 ,!re are a few purely me*anical ways ( solv+ "s ( ! simple cases ( sub/itution ciph]s b z a g5]al rule "s or all ( ! foll[+ det]m9ations mu/ be made3 #a4 ,by prep>ation ( a frequ5cy table = ! message we det]m9e :e!r "o or m sub/itution alphabets h be5 us$ &1 if "o only has be5 us$1 ?is table leads to ! solution4 #b4 ,by c]ta9 rules we det]m9e h[ _m alphabets h be5 us$1 if !re are m ?an "o1 & !n isolate & analyze ea* alphabet by means ( a frequ5cy table4 #c4 ,if ! two prec$+ /eps give no results we h to deal ) a ciph] ) a runn+ key1 a ciph] ( ! ,playfair type1 or a ciph] :]e two or m *>act]s are sub/itut$ = ea* lett] ( ! text4 ,"s special cases "u ?is ?ird head w be giv5 b1 9 g5]al1 milit>y ciph]s ( ! sub/itution class w usually be f\nd to come "u ! fir/ two heads1 on acc\nt ( ! "t & c>e requir$ 9 ! prep>ation & deciph]+ ( messages by ! la/ nam$ me?ods & ! necessity1 9 _m cases1 ( us+ complicat$ ma*9es = ^! processes4 ,case #d-;a4 ,message ,,obqfo ,,bpbrp ,,qbaml ,,obhif ,,pilfq ,,fjbox ,,(lnr ,,bixoz ,,el ,f ! recurr5ce ( ,b1 ,f & ,o1 we may conclude t a s+le sub/itution alphabet 0 us$ = ?is message4 ,if s & if ! alphabet runs 9 ! same ord] & direction z ! regul> alphabet1 ! simple/ way to discov] ! mean+ ( ! message is to take ! fir/ two words & write alphabets "u ea* lett] z foll[s1 until "s l9e makes s5se3 ,o ,b ,q ,f ,o ,b ,p ,b ,r ,p ,p ,c ,r ,g ,p ,c ,q ,c ,s ,q ,q ,d ,s ,h ,q ,d ,r ,d ,t ,r ,r ,e ,t ,i ,r ,e ,s ,e ,u ,s ,! ^w ,,retirese occurs 9 ! f\r? l9e1 &1 if ! :ole message be h&l$ 9 ?is way we f9d ! re/ ( ! f\r? l9e to read ,,u/$ ,,por ,,el ,,mismo ,,it9]>io ,,que ,,m>*o4 ,! message 0 enciph]$ us+ an alphabet :]e ,a ,x1 ,b ,y1 ,c ,z1 ,d ,a1 etc4 not+ t z ?is message is 9 ,spani% ! lett]s ,k & ,w d n appe> 9 ! alphabet4 ,case #d-;b4 ,message ,,hujzh ,,uiupn ,,ozyts ,,vqxmi ,,smomx ,,mqhud ,,umrei ,,sesju ,,ag ,?is is a message 9 ,spani%4 ,we w h&le x z 9 case #d-;a1 sett+ d[n ! :ole message4 ,,hujzhuiu ,,pnozy ,,tsv ,,qx ,,mismo ,,mxmqhudumr ,,eis ,,esjuag ,,ivlaivjv ,,qopaz ,,utx ,,ry ,a,a ,,nynrivevns ,,fjt ,,ftlvbh ,,jxmbjxlx ,,rpqba ,,vuy ,,sz ,,ozosjxfxot ,,glu ,,gumxci ,,lynclymy ,,sqrcb ,,xvz ,,ta ,,paptlygypu ,,hmv ,,hvnydj ,,mzodmznz ,,trsdc ,,yxa ,,ub ,,qbqumzhzqv ,,inx ,,ixozel ,,nap5aoa ,,u/$ ,,zyb ,,vc ,,rcrvnai>x ,,joy ,,jypafm ,,obqfobpb ,a,u ,,azc ,,xd ,,sdsxobjbsy ,,lpz ,,lzqbgn ,,pcrgpcqc ,,bad ,,ye ,,tetypclctz ,,mqa ,,m>*o ,,qd%qdrd ,,cbe ,,zf ,,ufuzqdmdua ,,nrb ,a,s ,,retirese ,,dcf ,,ag ,,vgv>5evb ,,osc ,a,q ,,edg ,,bh ,,xhxbsf(xc ,,ptd ,,feh ,,ci ,,yiyctgpgyd ,,que ,,gfi ,,dj ,,zjzduhqhze ,a,o ,,hgj ,,el ,,alaeviriaf ,,ihl ,a,m ,,bmbfxjsjbg ,,jim ,,cncgyltl* ,,ljn ,,dodhzmumdi ,,mlo ,,epeianvnej ,,nmp ,,fqfjbox(l ,,onq ,,grglcpypgm ,,por ,,h%mdqzqhn ,a,e ,,it9]>io ,a,d ,"h ea* ^w ( ! message comes out on a diff]5t l9e1 & not+ 9 ea* case ! lett] correspond+ to ,a1 we h ! ^w ,,quemados :i* is ! key4 ,! ciph] alphabet *ang$ ) ea* ^w ( ! message4 ,a v>iation ( ?is case is :]e ! ciph] alphabet *anges accord+ to a key ^w b ! *ange comes e five lett]s or e t5 lett]s ( ! message in/ead ( e ^w4 ,! text ( ! message c be pick$ up 9 ?is case ) a little /udy4 ,note 9 us+ case #d t if we are deciph]+ a ,spani% message we use ! alphabet )\t ,k or ,w z a rule1 al?o if ! lett]s ,k or ,w appe> 9 ! ciph] x is evid5ce t ! regul> ,engli% alphabet is us$4 ,case #e-;a4 ,message ,,dnwlw ,,mxyqj ,,anrsa ,,rlpte ,,cabcq ,,rlnec ,,lmiwl ,,xzqtt ,,qiwry ,,zwnsm ,,bknwr ,,ymapl ,,asdan ,?is message conta9s ,k & ,w & !re=e we expect ! ,engli% alphabet to be us$4 ,! frequ5cy ( occurr5ce ( ,a1 ,l1 ,n1 ,r & ,w has lead u to exam9e x "u case #d b )\t result4 ,let u set d[n ! fir/ two words & deciph] !m ) a ciph] disk set ,a to ,a & !n proce$ z 9 case #d4 ,ciph] message ,,dnwlwmxyqj ,deciph]$ ,a to ,a ,,xnepeodckr ,b ,,y(qfp$ls ,c ,,zpgrgqfemt ,d ,,aqh%rgfnu ,e ,,briti%gov ,! message is ?us f\nd to be enciph]$ ) a ciph] disk set ,a to ,e & ! text is3 ,,briti% ,,gov]nm5t ,,plac$ ,,contracts ,,) ,,foll[+ ,,firms ,,dur+ ,,septemb]4 ,case #e-;b4 ,same z case #d-;b except t ! ciph] message mu/ be deciph]$ by means ( a ciph] disk set ,a to ,a be=e proce$+ to make up ! columns ( alphabets4 ,! words ( ! deciph]$ message w be f\nd on sep>ate l9es1 ! l9es be+ indicat$ z a rule by a key ^w :i* c be det]m9$ z 9 case #d-;b4 ,! "q ( alphabetic frequ5cy has already be5 discuss$ 9 consid]+ ! me*anism ( language4 ,x is a conv5i5t ?+ to put ! frequ5cy tables 9 a graphic =m & to use a simil> graphic =m 9 comp>+ unkn[n alphabets ) ! /&>d frequ5cy tables4 ,= in/ance ! /&>d ,spani% frequ5cy table put 9 graphic =m is "h pres5t$ 9 ord] to comp>e ) x ! frequ5cy table = ! message discuss$ 9 case #d-;a4 ,/&>d ,spani% ,table = ,message frequ5cy table ,case #d-;a ,a #aaaaaaaaaaaaaaaaaaaaaaaaaaa #bg ,a #a #a ,b #aa #b ,b #aaaaaaa #g ,c #aaaaaaaaa #i ,c ,d #aaaaaaaaaa #aj ,d ,e #aaaaaaaaaaaaaaaaaaaaaaaaaaaa #bh ,e #a #a ,f #aa #b ,f #aaaaa #e ,g #aaa #c ,g ,h #aa #b ,h #a #a ,i #aaaaaaaaaaaa #ab ,i #aaa #c ,j #a #a ,j #a #a ,l #aaaaaaaaaa #aj ,l #aaa #c ,m #aaaaaa #f ,m #a #a ,n #aaaaaaaaaaaa #ab ,n #a #a ,o #aaaaaaaaaaaaaaaa #af ,o #aaaaaa #f ,p #aaaaa #e ,p #aaa #c ,q #aa #b ,q #aaa #c ,r #aaaaaaaaaaaaaaa #ae ,r #aa #b ,s #aaaaaaaaaaaaaa #ad ,s ,t #aaaaaaaa #h ,t ,u #aaaaaaa #g ,u ,v #aa #b ,v ,x ,x #aa #b ,y #aa #b ,y ,z #a #a ,z #a #a ,our fir/ assumption might be t ,b ,a & ,f ,e b x is evid5t at once t 9 t case1 ,s1 ,t1 ,u & ,v 7equal to ,r1 ,s1 ,t & ,u7 d n occur & a message ev5 ?is %ort )\t ,r1 ,s1 ,t or ,u is practically impossible4 ,by try+ ,b ,e we f9d t ! two tables agree 9 a g5]al way v well & ?is is all t c be expect$ ) su* a %ort message4 ,! long] ! message ! ne>] w\ld its frequ5cy table agree ) ! /&>d table4 ,note t if a ciph] disk has be5 us$1 ! alphabet runs ! o!r way & we mu/ c\nt upw>d 9 work+ ) a graphic table4 ,note also t if1 9 a fairly long message1 x is impossible to cord9ate ! graphic table1 read+ ei!r up or d[n1 ) ! /&>d table & yet "s lett]s occur mu* m frequ5tly ?an o!rs & "s d n occur at all1 we h a mix$ alphabet to deal )4 ,! example *os5 = case #f-;a is ( ?is "*4 ,an exam9ation ( ! frequ5cy table giv5 "u t case %[s t x be>s no graphic resemblance to ! /&>d table4 ,h[ev]1 z w be se5 9 case #g-;b1 ! prep>ation ( graphic tables enables u to /ate def9itely t ! same ord] ( lett]s is foll[$ 9 ea* ( a numb] ( mix$ alphabets4 ,g5]al ,rem>ks ,any sub/itution ciph]1 enciph]$ by a s+le alphabet compos$ ( lett]s1 figures or conv5tional signs1 c be h&l$ by ! me?ods ( case #f4 ,= example1 ! messages "u case #d-;a & #e-;a are easily solv$ by ^! me?ods4 ,b note t ! messages "u case #d-;b & #e-;b _c s be solv$ because sev]al alphabets are us$4 ,we w see lat] t !re are me?ods ( segregat+ ! diff]5t alphabets 9 "s cases :]e sev]al are us$ & !n ea* ( ! alphabets is to be h&l$ z bel[4 ,case #f-;a4 ,message ,,qdbyp ,,bxhys ,,oxpcp ,,y%cs ,,edrbs ,,zptpb ,,bscsb ,,p%sz ,,ajhcd ,,osexv ,,hpoda ,,pbpsz ,,bsvxy ,,x%cd ,?is message 0 receiv$ f a s\rce :i* makes u sure x is 9 ,spani%4 ,! occurr5ce ( ,b1 ,h1 ,p & ,s has tempt$ u to try ! fir/ two words z 9 case #d & #e b )\t result4 ,we n[ prep>e a frequ5cy table1 not+ at ! same "t ! prec$+ & foll[+ lett]4 ,?is latt] proce$+ takes little long] ?an ! prep>ation ( an ord9>y frequ5cy table & gives mo/ valuable in=mation4 ,frequ5cy ,table ,prefix ,suffix ,a #aa #b ,,zd ,,jp ,b #aaaaaaaa #h ,,dprpbspz ,,yxsbspps ,c #aaaaa #e ,,ph%h ,,pssdd ,d #aaaaa #e ,,qecoc ,,broa ,e #aa #b ,,ss ,,dx ,f ,g ,h #aaaaaa #f ,,xssjvs ,,ycscpc ,i ,j #a #a ,a ,h ,l ,m ,n ,o #aaa #c ,,sdp ,,xsd ,p #aaaaaaaaa #i ,,yxcztbhab ,,bcytbsobs ,q #a #a ,d ,r #a #a ,d ,b ,s #aaaaaaaaaaaa #ab ,,yycbbcphopbx ,,ohezcbhzezvh ,t #a #a ,p ,p ,u ,v #aa #b ,,xs ,,hx ,x #aaaaa #e ,,boevy ,,hpvys ,y #aaaa #d ,,bhpx ,,pssx ,z #aaa #c ,,sss ,,pab ,x is cle> f an exam9ation ( ?is table t we h to deal ) a s+le alphabet b "o 9 :i* ! lett]s d n occur 9 _! regul> ord]4 ,we may assume t ,p & ,s are probably ,a & ,e1 bo? on acc\nt ( ! frequ5cy ) :i* !y occur & ! v>iety ( _! prefixes & suffixes4 ,if ?is is s1 !n ,b & ,h1 are probably consonants & may repres5t ,r & ,n respectively4 ,d & ,x are !n v[els by ! same me?od ( analysis4 ,not+ t ,,hc occurs ?ree times & tak+ ,h z ,n we conclude t ,c is probably ,t4 ,sub/itute ^! values 9 ! la/ ?ree words ( ! message because ! lett]s assum$ occur r frequ5tly !re4 ,,pbpszbsvxyx%cd ,i ,i ,i ,,arae,,re ,,ent ,o ,o ,o ,n[ ,z is always prefix$ by ,s & may be ,l4 ,tak+ ,x,i & ,d,o1 7!y are c]ta9ly v[els71 ,v,g & ,y,m1 we h ,,ara ,,el ,,regimi5to ,sub/itut+ ^! values 9 ! re/ ( ! message we h ,q ,,dbypbxh ,,ysoxpcp ,,y%cs$ ,,rbszptpb ,,orm>9 ,,me,,iata ,,m5te,o ,,rela,,ar ,,bscsb ,,p%sz ,,ajhcd ,,osexvhpoda ,,ret] ,,a5el ,,nto ,e,,igna,o ,we may n[ take ,q,f1 ,o,d1 ,e,s1 ,r,b1 ,t,c1 ,a,p & ,j,u & ! message is complete4 ,we are assi/$ 9 our la/ assumption by not+ t ,s,e & ,e,s1 etc41 & we may on t basis recon/ruct ! entire alphabet4 ,! lett]s 9 p>5!sis d n occur 9 ! message b may be safely assum$ to be correct4 ,ord9>y ,a ,b ,c ,d ,e ,f ,g ,h ,i ,j ,l ,m ,n ,o ,p ,q ,r ,s ,t ,u ,v ,x ,y ,z ,ciph] ,p ,r ,t ,o ,s 7,q7 7,v7 ,n 7,x7 7,u7 7,z7 7,y7 7,h7 ,d ,a ,f ,b ,e ,c ,j ,g ,i ,m ,l ,x is always well to attempt ! recon/ruction ( ! entire alphabet = use 9 case any m ciph] messages writt5 9 x are receiv$4---- ,case #f-;b4 ,message ,lt4 ,j4 ,b4 ,smi?1 ,royal ,fly+ ,corps1 ,calais1 ,france4 ,,dacft ,,rrbha ,,mo\e ,,a5oi ,,ztiet ,,asmos ,,eohie ,,yockf ,,nohoe ,,n\? ,,omeah ,,nilgo ,,osahu ,,oh\e ,,ap*s ,,tlnda ,,cft5 ,,intwn ,,bafoh ,,groht ,,aeioh ,,abris ,,odacf ,,trr5 ,,o/sm ,,aybis ,,dft5 ,,efaph ,,osmni ,,ztiea ,,hlill ,,tws\ ,,gd5o ,,u?om ,,eahbh ,,amo\ ,,eayoe ,,qisuu ,,oleha ,,d5oe ,,nhooq ,,obbor ,,tslho ,,baheo ,,ubhob ,,ihtsw ,,enoho ,,pahih ,,ituas ,,bihtl ,graham-,:ite4 ,! address & signature indicate t ?is message is 9 ,engli%4 ,!re are #bej lett]s 9 ! ciph]2 ! v[els ,,aei\ occur #aji times or #dc4f1 ! lett]s ,,lnr/ occur #fb times or #bd4h1 & ! lett]s ,,kqvxz occur #e times or #b4 ,! proportion 9 ! case ( ! v[els is some:at too l>ge &1 9 ! case ( ! lett]s ,,lrn/1 x is too small4 ,x is !n que/ionable :e!r ?is is a transposition ciph] al?o1 at fir/ glance x might appe> to be "o4 ,on exam9ation = p>ts ( possible words we are at once /ruck by ! occurr5ce at irregul> int]vals ( recurr+ gr\ps1 viz3 ,,dacftrr ,,eno ,,bhamo\ea ,,dacft5 ,,en\?omeah ,,bhamo\ea ,,eno ,,dacftrr ,,d5\?omeah ,,iztie ,,ft5 ,,d5o ,,iztie ,,eno ,?is is a /rong indication t ! ciph] is a sub/itution ciph]1 s1 to make an exam9ation a frequ5cy table w be con/ruct$4 ,frequ5cy ,table ,a ,b ,c ,d ,e ,f ,g ,h ,i ,j ,k ,l ,m #bc #aa #g #f #bd #g #c #bf #af #j #a #h #h ,n ,o ,p ,q ,r ,s ,t ,u ,v ,w ,x ,y ,z #ae #cf #c #b #h #ad #ag #aa #a #c #j #c #b ,sup]ficially1 ?is looks l a normal frequ5cy table1 b ,o is ! dom9ant lett]1 foll[$ by ,h1 ,e1 ,a1 ,t1 ,i1 ,n1 ,s1 9 ! ord] nam$4 ,x is c]ta9ly ,case #f if x is a sub/itution ciph] at all4 ,let u see :at c be done by assum+ ,o,e2 ! triplet ,,eno1 occurr+ six times might well be ,,! & ,e,t & ,n,h4 ,a glance at ! frequ5cy table %[s ?is to be reasonable4 ,n[ sub/itute ^! lett]s 9 "s likely gr\ps4 ,,fnoho5o becomes ,,he,,e!2 ,,ft5 becomes ,,?2 ,,eno5ho becomes ,,!?,e2 ,,enoho becomes ,,!,e4 ,a bit ( /udy w %[ t ,f,w1 ,t,i & ,h,r & ! frequ5cy table be>s ?is out except t ,h7,r7 seems to occur too frequ5tly4 ,! recurr+ gr\ps conta9+ ,,dac 7see above7 occur 9 su* a way t we may be sure ,,dac is "o ^w1 ,,ftrr is ano!r & ,,ft57,,)7 is a ?ird4 ,n[ ,,ftrr becomes ,,wi1 :i* c only be complet$ by a d\ble lett]4 ,,ll fills ! bill & we may say ,r,l4 ,z ,,dac />ts ! message & is foll[$ by ,,ftrr 7,,w7 x is reasonable to try ,,dac,,y4 ,look+ up ,,dac 9 ! frequ5cy table x is evid5t t we /ra9 no?+ by ?is assumption4 ,we n[ h3 ,lett]s ( ciph] ,,ontahecfd ,lett]s ( message ,,ehiortuwy ,n[ take ! gr\p ,,en\?omeah :i* occurs twice4 ,?is becomes ,,!,,ire,,tor & if we sub/itute ,u,d & ,m,c we h ,,! ,,director4 ,next ! gr\p 7,,ftrr7,,bhamo\ea becomes 7,,w7 ,,roce$to & ! context gives ^w ) miss+ lett] z ,,proce$1 f :i* ,b,p4 ,next ! gr\p 7,,eno7 ,,iztietasmoseohieyock7,,fnoho7 becomes 7,,!7,i,,tio,,ce,,t],t,,eu7,,:]e7 & ! gr\p 7,,ft57,,efaphosmniztieahl becomes 7,,)7,,two,,re,,*,i,,tor4 ,! sub/itution ( ,a = ,i1 ,v = ,z1 ,n = ,s & ,f = ,p makes ! latt] gr\p read 7,,) ,,two ,,fr5* ,,aviators & ! =m] read 7,,!7,,aviation ,,c5t] ,,at ,,eu7,,:]e74 ,n[ ! ^w ,,yock 7,,eu7 is ! "n ( a place1 evid5tly4 ,we f9d ano!r gr\p conta9+ ,y1 viz3 ,,eno/smaybisd :i* becomes ,,!n9co,,pany s t evid5tly we %\ld sub/itute ,m = ,y4 ,! o!r occurr5ce ( ,y 7,m7 is 9 ! gr\p ,,eayoeqisu :i* becomes ,,tomet,,&4 ,a reasonable k ( geography gives u ! words ,,meux & ,,metz s t ,x %\ld be sub/itut$ = ,k & ,z = ,q4 ,we n[ h suffici5t lett]s = a complete deciph]+ ( ! message4 ,lett]s ( ciph] ,,abcdefghiklmnopqr/uvwyz ,lett]s ( message ,,opuytw,,raxs*efzlnid,,mv ,! message deciph]s3 ,,y ,,w ,,proce$ ,,to ,,! ,,aviation ,,c5t] ,,at ,,meux ,,:]e ,,! ,,director ,,has ,,e5 ,,ord]$ ,,to ,,furni% ,,y ,,) ,a ,,hi,h ,,p[] ,,l]iot ,,a]oplane4 ,,y ,,w ,,!n ,,9 ,,company ,,) ,,two ,,fr5* ,,aviators ,,assi,,n$ ,y ,,! ,,director ,,proce$ ,,to ,,metz ,,& ,,de/roy ,,! ,,?ree ,,zeppel9s ,,report$ ,,prep>9 ,,!re ,,= ,a ,,raid ,,on ,,p>is4 ,! sub/itution ( ,b = ,g1 ,g = ,w & ,k = ,v completes ! ciph]4 ,?is ciph] is difficult only because ! ciph] alphabet is made up1 n haphaz>d1 b sci5tifically ) prop] consid]ation = ! natural frequ5cy ( occurr5ce ( ! lett]s4 ,9 ciph] "w x is dang]\s to neglect prop] analysis & jump at conclusions4 ,9 ! /udy ( ,mexican sub/itution ciph]s1 sev]al alphabets h be5 f\nd :i* are made up 9 a g5]al way1 l ! "o discuss$ 9 ?is case4 ,case #f-;c4--,x is a conv5i5ce 9 deal+ ) ciph]s made up ( numb]s or conv5tional signs to sub/itute arbitr>y lett]s = ! numb]s & signs4 ,suppose we h ! message3 88#b #dex#ae 7#h #ax#d #d #fx8 #h99x#d #f99 #d ,by arbitr>y sub/itution ( lett]s ?is is made ,,abbcd ,,efghf ,,ijkdl ,,ddhge ,,md$m ,,ngbda ,,kdoge ,,npopd ,,ma$a ,?is message is n[ 9 conv5i5t %ape to h&le z ,case #f-;a & on solution is f\nd to read3 ,,all ,,p]sons ,,h ,,be5 ,,ord]$ ,,to ,,leave ,,=tifi$ ,,area4 ,9 ! same way ! message #agbc #cbbc #bhbe #ahbh #cfcj #bccf #adbc #bhbg #bcbd #cabj #bcag #cabc #cjcf #babj #bdae #cjbi #aeab #bhca #agba #bgae #bhaa #bgae #aibc #cjcj #abae #aacj #babh #cfbc is f\nd to be made up entirely ( numb]s betwe5 #aa & #cf ) ! numb]s #bc1 #bh & #cj occurr+ mo/ frequ5tly4 ,?is imm$iately sugge/s an alphabet made up ( ! numb]s f #aa to #cf inclusive & ea* ciph] gr\p ( figures repres5ts two lett]s4 ,by arbitr>y sub/itution ( lett]s = gr\ps ( two numb]s we obta93 ,,ab ,,cb ,,de ,,fd ,,gh ,,bg ,,ib ,,dj ,,bk ,,lm ,,ba ,,lb ,,hg ,,nm ,,op ,,hq ,,pr ,,dl ,,an ,,jp ,,ds ,,jp ,,tb ,,hh ,,rp ,,% ,,nd ,,gb & ?is message is also 9 %ape to h&le z ,case #f-;a4 ,x reads1 on solution1 ,,sev5 ,,hundr$ ,,m5 ,,left ,,ye/]day ,,= ,,po9ts ,,on ,,l[] ,,rio ,,gr&e4 ,,*apt] ,,vii ,we w n[ consid] ! class ( sub/itution ciph]s :]e a numb] ( alphabets are us$1 ! numb] & *oice ( alphabets dep5d+ on a key ^w or equival5t & be+ us$ p]iodically ?r\gh\t ! message4 ,9 ?is class belong ! me?ods ( ,vig5]e1 ,porta1 ,beau=t1 ,/4 ,cyr1 & _m o!rs4 ,^! me?ods date back sev]al hundr$ ye>s1 b v>iations ( !m are con/antly appe>+ z new ciph]s4 ,! ,l>rabee ciph]1 us$ = communication betwe5 gov]nm5t dep>tm5ts1 is ! ,vig5]e ciph] ( ! #ag? ,c5tury4 ,! ciph] disk me?od is practically ! ,vig5]e ciph] ) rev]s$ alphabets4 ,9 us+ ^! ciph]s1 !re is provid$ a numb] ( diff]5t ciph] alphabets1 usually tw5ty-six1 & ea* ciph] alphabet is id5tifi$ by a diff]5t lett] or numb]4 ,a key ^w or phrase 7or key numb]7 is agre$ ^u by ! correspond5ts4 ,! message to be enciph]$ is writt5 9 l9es conta9+ a numb] ( lett]s :i* is a multiple ( ! numb] ( lett]s ( ! key4 ,! key is writt5 z ! fir/ l9e4 ,!n ea* column "u a lett] ( ! key is enciph]$ by ! ciph] alphabet p]ta9+ to t lett] ( ! key4 ,= example1 let u take ! message1 ,all radio messages mu/ h]eaft] be put 9 ciph]1 ) ! key ,grant1 us+ ! ,vig5]e ciph] alphabets giv5 bel[4 ,ea* ( ^! alphabets is id5tifi$ by ! fir/ or left h& lett] :i* repres5ts ,a ( ! text4 ,we ?us w use 9 turn ! alphabets beg9n+ ) ,g1 ) ,r1 ) ,a1 ) ,n1 & ) ,t4 ,g ,r ,a ,n ,t ,g ,r ,a ,n ,t ,a ,l ,l ,r ,a ,d ,i ,o ,m ,e ,s ,s ,a ,g ,e ,s ,m ,u ,s ,t ,h ,e ,r ,e ,a ,f ,t ,e ,r ,b ,e ,p ,u ,t ,i ,n ,c ,i ,p ,h ,e ,r ,us+ ! alphabet indicat$ by ,g1 we get ,g ,j ,y ,y ,n ,l ,k ,t ,k ,cont9u+ = ! o!r alphabets1 we get ,g ,c ,l ,e ,t ,j ,z ,o ,z ,x ,y ,j ,a ,t ,x ,y ,d ,u ,f ,m ,n ,v ,r ,r ,t ,l ,k ,e ,e ,u ,k ,g ,u ,g ,b ,t ,t ,i ,c ,a ,k ,i ,?is me?od ( arrang+ ! message into l9es & columns & !n enciph]+ :ole columns ) ea* ciph] alphabet is mu* %ort] ?an ! me?od ( h&l+ ea* lett] ( ! message sep>ately4 ,! *ance ( error is also greatly r$uc$4 ,all ^! ciph] me?ods c be op]at$ by means ( squ>es conta9+ ! v>i\s alphabets1 ciph] disks or arrangem5ts ( fix$ & slid+ alphabets4 ,= example1 ?is 0 ! orig9al ciph] ( ,vig5]e3 ,a ,b ,c ,d ,e ,f ,g ,h ,i ,j ,k ,l ,m ,n ,o ,p ,q ,r ,s ,t ,u ,v ,w ,x ,y ,z ,b ,c ,d ,e ,f ,g ,h ,i ,j ,k ,l ,m ,n ,o ,p ,q ,r ,s ,t ,u ,v ,w ,x ,y ,z ,a ,c ,d ,e ,f ,g ,h ,i ,j ,k ,l ,m ,n ,o ,p ,q ,r ,s ,t ,u ,v ,w ,x ,y ,z ,a ,b ,d ,e ,f ,g ,h ,i ,j ,k ,l ,m ,n ,o ,p ,q ,r ,s ,t ,u ,v ,w ,x ,y ,z ,a ,b ,c ,e ,f ,g ,h ,i ,j ,k ,l ,m ,n ,o ,p ,q ,r ,s ,t ,u ,v ,w ,x ,y ,z ,a ,b ,c ,d ,f ,g ,h ,i ,j ,k ,l ,m ,n ,o ,p ,q ,r ,s ,t ,u ,v ,w ,x ,y ,z ,a ,b ,c ,d ,e ,g ,h ,i ,j ,k ,l ,m ,n ,o ,p ,q ,r ,s ,t ,u ,v ,w ,x ,y ,z ,a ,b ,c ,d ,e ,f ,h ,i ,j ,k ,l ,m ,n ,o ,p ,q ,r ,s ,t ,u ,v ,w ,x ,y ,z ,a ,b ,c ,d ,e ,f ,g ,i ,j ,k ,l ,m ,n ,o ,p ,q ,r ,s ,t ,u ,v ,w ,x ,y ,z ,a ,b ,c ,d ,e ,f ,g ,h ,j ,k ,l ,m ,n ,o ,p ,q ,r ,s ,t ,u ,v ,w ,x ,y ,z ,a ,b ,c ,d ,e ,f ,g ,h ,i ,k ,l ,m ,n ,o ,p ,q ,r ,s ,t ,u ,v ,w ,x ,y ,z ,a ,b ,c ,d ,e ,f ,g ,h ,i ,j ,l ,m ,n ,o ,p ,q ,r ,s ,t ,u ,v ,w ,x ,y ,z ,a ,b ,c ,d ,e ,f ,g ,h ,i ,j ,k ,m ,n ,o ,p ,q ,r ,s ,t ,u ,v ,w ,x ,y ,z ,a ,b ,c ,d ,e ,f ,g ,h ,i ,j ,k ,l ,n ,o ,p ,q ,r ,s ,t ,u ,v ,w ,x ,y ,z ,a ,b ,c ,d ,e ,f ,g ,h ,i ,j ,k ,l ,m ,o ,p ,q ,r ,s ,t ,u ,v ,w ,x ,y ,z ,a ,b ,c ,d ,e ,f ,g ,h ,i ,j ,k ,l ,m ,n ,p ,q ,r ,s ,t ,u ,v ,w ,x ,y ,z ,a ,b ,c ,d ,e ,f ,g ,h ,i ,j ,k ,l ,m ,n ,o ,q ,r ,s ,t ,u ,v ,w ,x ,y ,z ,a ,b ,c ,d ,e ,f ,g ,h ,i ,j ,k ,l ,m ,n ,o ,p ,r ,s ,t ,u ,v ,w ,x ,y ,z ,a ,b ,c ,d ,e ,f ,g ,h ,i ,j ,k ,l ,m ,n ,o ,p ,q ,s ,t ,u ,v ,w ,x ,y ,z ,a ,b ,c ,d ,e ,f ,g ,h ,i ,j ,k ,l ,m ,n ,o ,p ,q ,r ,t ,u ,v ,w ,x ,y ,z ,a ,b ,c ,d ,e ,f ,g ,h ,i ,j ,k ,l ,m ,n ,o ,p ,q ,r ,s ,u ,v ,w ,x ,y ,z ,a ,b ,c ,d ,e ,f ,g ,h ,i ,j ,k ,l ,m ,n ,o ,p ,q ,r ,s ,t ,v ,w ,x ,y ,z ,a ,b ,c ,d ,e ,f ,g ,h ,i ,j ,k ,l ,m ,n ,o ,p ,q ,r ,s ,t ,u ,w ,x ,y ,z ,a ,b ,c ,d ,e ,f ,g ,h ,i ,j ,k ,l ,m ,n ,o ,p ,q ,r ,s ,t ,u ,v ,x ,y ,z ,a ,b ,c ,d ,e ,f ,g ,h ,i ,j ,k ,l ,m ,n ,o ,p ,q ,r ,s ,t ,u ,v ,w ,y ,z ,a ,b ,c ,d ,e ,f ,g ,h ,i ,j ,k ,l ,m ,n ,o ,p ,q ,r ,s ,t ,u ,v ,w ,x ,z ,a ,b ,c ,d ,e ,f ,g ,h ,i ,j ,k ,l ,m ,n ,o ,p ,q ,r ,s ,t ,u ,v ,w ,x ,y ,! fir/ horizontal alphabet is ! alphabet ( ! pla9 text4 ,ea* sub/itution alphabet is designat$ by ! lett] at ! left ( a horizontal l9e4 ,= example1 if ! key ^w is ,,bad1 ! second1 fir/ & f\r? alphabets are us$ 9 turn & ! ^w ,,w is enciph]$ ,,xiom4 ,! ,l>rabee ciph] is m]ely a slightly diff]5t arrangem5t ( ! ,vig5]e ciph] & is pr9t$ on a c>d 9 ?is =m3 ---------------------------------- ,a ,,abcdefghijklmnopqr/uvwxyz abcdefghijklmnopqr/uvwxyz ---------------------------------- ,b ,,abcdefghijklmnopqr/uvwxyz bcdefghijklmnopqr/uvwxyza ---------------------------------- ,c ,,abcdefghijklmnopqr/uvwxyz cdefghijklmnopqr/uvwxyzab ---------------------------------- etc4 ---------------------------------- ,y ,,abcdefghijklmnopqr/uvwxyz yzabcdefghijklmnopqr/uvwx ---------------------------------- ,z ,,abcdefghijklmnopqr/uvwxyz zabcdefghijklmnopqr/uvwxy ---------------------------------- ,! l>ge lett]s at ! left are ! lett]s ( ! key ^w4 ,x w be not$ t ^! lett]s correspond to ! fir/ lett]s ( ! ciph] alphabets 79 small lett]s7 z 9 ! ,vig5]e ciph]4 ,a mu* simpl] arrangem5t ( ! ,vig5]e ciph] is ! use ( a fix$ & slid+ alphabet4 ,ei!r ! fix$ or slid+ alphabet mu/ be d\ble 9 ord] to get co9cid5ce = e lett] :5 ,a is set to ! lett] ( ! key ^w4 ,fix$ ,alphabet ( ,text ,,abcdefghijklmnopqr/uvwxyzabcdefghijklm nopqr/uvwxyz ---------------------------------------- ------------- ,,abcdefghijklmnopqr/uvwxyz ,movable ,alphabet ( ,ciph] ---------------------------------------- --- ,z %[n "h1 ,a ( ! fix$ or text alphabet co9cides ) ,t ( ! movable ciph] alphabet4 ,?is is ! sett+ :]e ,t is ! lett] ( ! key ^w 9 use4 ,! l[] movable alphabet is mov$ = ea* lett] ( ! message & ! ,a ( ! fix$ alphabet is made to co9cide 9 turn ) ea* lett] ( ! key be=e ! correspond+ lett] ( ! text is enciph]$4 ,x is obvi\sly only a /ep f ?is arrangem5t to t ( a ciph] disk1 :]e ! fix$ alphabet1 7a s+le "o w n[ s]ve7 is pr9t$ 9 a circle & ! movable alphabet1 also 9 a circle1 is on a sep>ate rotatable disk4 ,co9cid5ce ( any lett] on ! disk ) ,a ( ! fix$ alphabet is obta9$ by rotat+ ! disk4 ,! well kn[n ,u4 ,s4 ,army ,ciph] ,disk has j su* an arrangem5t ( ! fix$ alphabet b ! alphabet ( ! disk is rev]s$4 ,?is has sev]al advantages 9 simplicity ( op]ation b none 9 increas+ ! indeciph]ability ( ! ciph] prep>$ ) x4 ,! arrangem5t ( fix$ & slid+ alphabets :i* is equival5t to ! ,u4 ,s4 ,army ciph] disk is ?is3 ,fix$ ,alphabet ,,abcdefghijklmnopqr/uvwxyzabcdefghijklm nopqr/uvwxyz ---------------------------------------- -------------- ,,zyxwvutsrqponmlkjihgf$cba ,movable ,alphabet ---------------------------------------- -- ,x w be notic$ t ) ?is arrangem5t ( runn+ ! alphabets 9 opposite directions1 x becomes immat]ial :i* alphabet is us$ = ! text & :i* = ! ciph] = if ,a ,g !n ,g ,a4 ,?is is n true ( ! ,vig5]e ciph]4 ,x is p]fectly feasible to sub/itute a c>d = ! ,u4 ,s4 ,army ciph] disk4 ,x w\ld h ?is =m3 ,,abcdefghijklmnopqr/uvwxyz #a ,,azyxwvutsrqponmlkjihgf$cb #b ,,bazyxwvutsrqponmlkjihgf$c #c ,,cbazyxwvutsrqponmlkjihgf$ etc4 #be ,,yxwvutsrqponmlkjihgf$cbaz #bf ,,zyxwvutsrqponmlkjihgf$cba ,! fir/ horizontal l9e is ! alphabet ( ! text4 ,! o!r tw5ty-six l9es are ! ciph] alphabets ea* correspond+ to ! lett] ( ! key ^w :i* is at ! left ( ! l9e4 ,"o ( ! ciph]s ( ,porta 0 prep>$ ) a c>d ( ?is k9d3 ----------------------------- ,,ab ,,abcdefghijklm ,,nopqr/uvwxyz ----------------------------- ,,cd ,,abcdefghijklm ,,znopqr/uvwxy ----------------------------- ,,ef ,,abcdefghijklm ,,yzabcdefghijk ----------------------------- etc4 ----------------------------- ,,wx ,,abcdefghijklm ,,pqr/uvwxyzno ----------------------------- ,,yz ,,abcdefghijklm ,,opqr/uvwxyzn ----------------------------- ,9 ?is ciph] ! l>ge lett]s at ! left correspond to ! lett]s ( ! key &1 9 ea* alphabet1 ! l[] lett] is sub/itut$ = ! upp] & vice v]sa4 ,= example1 ) key ,,bad to enciph] ,,w we w\ld get ,,jvxy4 ,note t ) ei!r ,b or ,a z ! key lett]1 ! fir/ alphabet w\ld be us$4 ,a comb9ation ( ! ,vig5]e & ,porta ciph]s is ?is3 ---------------------------------- ,a ,,abcdefghijklmnopqr/uvwxyz ,,abcdefghijklmnopqr/uvwxyz ---------------------------------- ,,bc ,,abcdefghijklmnopqr/uvwxyz ,,bcdefghijklmnopqr/uvwxyza ---------------------------------- ,,de ,,abcdefghijklmnopqr/uvwxyz ,,cdefghijklmnopqr/uvwxyzab ---------------------------------- etc4 ---------------------------------- ,,vw ,,abcdefghijklmnopqr/uvwxyz ,,lmnopqr/uvwxyzabcdefghijk ---------------------------------- ,,xy ,,abcdefghijklmnopqr/uvwxyz ,,mnopqr/uvwxyzabcdefghijkl ---------------------------------- ,z ,,abcdefghijklmnopqr/uvwxyz ,,nopqr/uvwxyzabcdefghijklm ---------------------------------- ,"h aga9 ! l>ge lett]s at ! left correspond to ! lett]s ( ! key &1 9 ea* pair ( alphabets1 ! upp] "o is t ( ! pla9 text & ! l[] is t ( ! ciph]4 ,?is ciph] c also be op]at$ by a fix$ & slid+ alphabet4 ,fix$ ,alphabet ( ,text3 ,,abcdefghijklmnopqr/uvwxyzabcdefghijklm nopqr/uvwxyz ---------------------------------------- -------------- ,,abcdefghijklmnopqr/uvwxyz ,slid+ ,alphabet ( ,ciph] ,index ---------------------------------------- -- ,,bdfhjlnprtvx ,a ,z ,lett]s ( ,key4 ,,cegikmoqsuwy ,! o!r ciph]s m5tion$ are m]ely v>iations ( ^! t h be5 discuss$4 ,x is immat]ial1 9 ! foll[+ analysis1 :i* v>iety has be5 us$4 ,! analysis is really bas$ on :at c be done ) a ciph] made up ) a mix$ ciph] alphabet :i* may be mov$ ) ref]5ce to ! fix$ alphabet ( ! text1 7,see ,case #g-;b74 ,cle>ly ?is is a mu* m difficult proposition ?an deal+ ) a ciph] 9 :i* ! ciph] alphabets run 9 _! regul> sequ5ce1 ei!r backw>d or =w>d4 ,9 fact1 9 ! analysis ( ,case #g1 we may consid] any ciph] prep>$ by ! me?od ( ,vig5]e or any ( its v>iations z a special & simple case4 ,x 0 long ago discov]$ t1 9 any ciph] ( ?is class1 7#a7 two l gr\ps ( lett]s 9 ! ciph] are mo/ probably ! result ( two l gr\ps ( lett]s ( ! text enciph]$ by ! same alphabets & 7#b7 ! numb] ( lett]s 9 "o gr\p plus ! numb] ( lett]s to ! beg9n+ ( ! second gr\p is a multiple ( ! numb] ( alphabets us$4 ,x is evid5t1 ( c\rse1 t we may h simil> gr\ps 9 ! ciph] :i* are n ! result ( enciph]+ simil> gr\ps ( ! text by ! same alphabets b if we take all recurr+ gr\ps 9 a message & inve/igate ! numb] ( int]v5+ lett]s1 we w f9d t ! majority ( su* cases w con=m to ^! two pr9ciples4 ,*ang+ ! key ^w & message to illu/rate m cle>ly ! above po9ts1 ! foll[+ is quot$ f ! ,signal ,book1 #aiad1 ) ref]5ce to ! use ( ! ciph] disk 9 prep>+ a message ) a key ^w4 #b --,?is simple disk c be us$ ) a ciph] ^w or1 pref]ably1 ciph] words1 kn[n only to ! correspond5ts4444 ,us+ ! key ^w 'disk' to enciph] ! message ',artill]y comm&] w ord] all guns )drawn1' we w proce$ z foll[s3 ,write out ! message to be enciph]$ & above x write ! key ^w 444 lett] ov] lett]1 ?us3 ,,disk,,disk,,disk,,disk,,disk,,disk,,di sk,,disk,,disk,,disk,,dis ,,arti,,ll],,ycom,,m&,,erwi,,llor,,d]a,, llgu,,nswi,,?dr,,awn ,,drzc,,sxot,,fgey,,rifh,,zrwc,,sxet,,ae bk,,sxmq,,qqwc,,xbpt,,dmp ,n[ br+ ! 'a' ( ! upp] disk "u ! fir/ lett] ( ! key ^w on ! l[] disk1 9 ?is case ',d'4 ,! fir/ lett] ( ! message to be enciph]$ is ',a'3 'd' is f\nd to be ! lett] connect$ ) ',a'1 & x is put d[n z ! fir/ ciph] lett]4 ,! lett] 'a' is !n br\ght "u ',i' :i* is ! second lett] ( ! key ^w4 ',r' is to be enciph]$ & 'r' is f\nd to be ! second ciph] lett]4444 ,proce$ 9 ?is mann] until ! la/ lett] ( ! key ^w is us$ & beg9n+ aga9 ) ! lett] ',d'1 s cont9ue until all lett]s ( ! message h be5 enciph]$4 ,divid$ into gr\ps ( five lett]s1 x w be z foll[s3 ,,drzcs ,,xotfg ,,eyrif ,,hzrwc ,,sxeta ,,ebksx ,,mqqqw ,,ckbpt ,,dmf4 ,s mu* = ! ,signal ,book2 n[ let u exam9e ! above message = pairs or simil> gr\ps & c\nt ! int]v5+ lett]s to demon/rate pr9ciples 7#a7 & 7#b72 ,,csx--,,csx #af #dd ,,sx--,,sx #af #dd ,,sx--,,sx #h #bd ,,wc--,,wc #af #dd ,! key ^w might conta9 #b1 #d or #h lett]s f ! evid5ce b we may elim9ate #b z unlikely & prep>ation ( frequ5cy tables ( ea* ( ! f\r alphabets w\ld soon %[ t #d is ! correct numb]4 ,a lat] & m ext5sive example 7,case #g-;a7 w %[ pairs n sep>at$ by multiples ( ! numb] ( alphabets us$1 b ! evid5ce 9 ne>ly e case w be practically conclusive4 ,especially is ?is s if *ance assi/s u by giv+ gr\ps ( ?ree or m lett]s l ! gr\p ,,csx 9 ! above example4 ,! numb] ( alphabets hav+ be5 det]m9$ ea* alphabet is h&l$ by ! me?ods ( ,case #f already discuss$4 ,case #g-;a4--,! foll[+ message appe>$ 9 ! p]sonal column ( a ,london pap]3 ,m4 ,b4 ,w deposit #bg #ads #e;d tomorr[1 & ! next day we f9d ?is "o3 ,m4,b4 ,,ct ,,osb ,,uhgi ,,tp ,,ipewf ,h ,,cewil ,,n/tle ,,fjnvx ,,xtyls ,,fwkkhi ,,bjlsi ,,sq ,,voi ,,bksm ,,xmkul ,,sk ,,nvponpn ,,gsw ,,ol4 ,,ieag ,,npsi ,,hyjisfz ,,cyy ,,npuxqg ,,tprja ,,vxmxi ,,ap ,,ehvppr ,,? ,,wppnel4 ,,uvzua ,,mmyvsf ,,knts ,,zsz ,,uajpq ,,dlmmjxl ,,jr ,,ra ,,portelogj ,,csultwni ,,xmkuhw ,,xgln ,,elcp[y ,,ol4 ,,uljtl ,,bvj ,,tlbwtpz ,,xld ,k ,,zisznk ,,osy ,,dl ,,ryjuajssgk4 ,,tlfns ,,uvd ,,vv ,,fqgcyl ,,fjhvsi ,,yjl ,,nexv ,,po ,,wtol ,,pyyyh% ,,gqboh ,,agztiq ,,eyfax ,,ypmp ,,sqa ,,ci ,,xeyvxnppaii ,,uv ,,tlftwmc ,,fu ,,wbwxguhiwu4 ,,aiiwg ,,hsi ,,yjvti ,,bjv ,,xmqn ,,sfx ,,dqb ,,lrty ,,tz ,,qtxlnisvz4 ,,gift ,,aii ,,uqsjgj ,,ohz ,,xf[fv ,,bkai ,,ctwy ,,dswtltttpkfrhg ,,ivx ,,qcafv ,,tp ,,diis ,,jbf ,,esf ,,jsc ,,mccf ,,hngk ,,esbp ,,djpq ,,nlu ,,ctw ,,rosb ,,csm4 ,! messages 9 "q appe>$ 9 an ,engli% newspap]4 ,x is fair to presume !n t ! ciph] is 9 ,engli%4 ,?is is *eck$ negatively by ! fact t x conta9s ! lett] ,w :i* is n us$ 9 any ( ! ,lat9 languages & t ! la/ fifte5 words ( ! message consi/ ( f two to f\r lett]s ea*1 an impossible ?+ 9 ,g]man4 ,x conta9s #ajh gr\ps :i* are probably words1 z !re are #dgc lett]s or an av]age ( #d4d lett]s p] gr\p1 :ile we normally expect an av]age ( ab\t #e lett]s p] gr\p4 ,! v[els ,,aei\ numb] #ij & ! lett]s ,,jkqxz numb] #gh4 ,x is ?us a sub/itution ciph] 7#bj ( #dgcid4f74 ,recurr+ words & simil> gr\ps are ,,aiiwg1 ,,aii2 ,,bksm1 ,,bkai2 ,,ct1 ,,ctwy1 ,,ctw2 ,,dlmmjxl1 ,,dl2 ,,esf1 ,,esbp2 ,,fjnvx1 ,,fjhvsi2 ,,npsi1 ,,npuxqg2 ,,osb1 ,,osy1 ,,rosb2 ,,ol1 ,,ol2 ,,portelogj1 ,,po2 ,,sq1 ,,sqa2 ,,tp1 ,,tp2 ,,tlbwtpz1 ,,tlfns1 ,,tlftwmc2 ,,uvzua1 ,,uvd1 ,,uv2 ,,xmkul1 ,,xmkuhw2 ,,yjl1 ,,yjvti4 ,frequ5cy ,table = ! ,message ,a ,b ,c ,d ,e ,f ,g ,h ,i ,j ,k ,l ,m ,n ,o ,p ,q ,r ,s ,t ,u ,v ,w ,x ,y ,z #ae #ac #ae #h #ac #bj #af #af #cj #ba #ac #bg #ad #ai #ae #bf #ac #i #cc #cj #ag #ab #ai #bj #ai #aa ,?is cle>ly elim9ates ,cases #d1 #e & #f4 ,ref]r+ to ! recurr+ words & gr\ps above not$1 we figure ! numb] ( lett]s betwe5 ea*4 ,,aii 444 ,,aii #de #cce ,,bk 444 ,,bk #cde #bcce ,,ct 444 ,,ct #djc ,no factors ,,ctw 444 ,,ctw #fj #bbce ,,dl 444 ,,dl #ge #cee ,,es 444 ,,es #ad #bg ,,fj 444 ,,fj #ahg ,no factors ,,np 444 ,,np #ad #bg ,,ol 444 ,,ol #abj #bbbce ,,os 444 ,,os #bbj #aabbe ,,osb 444 ,,osb #dfe #cace ,,po 444 ,,po #aje #gce ,,sq 444 ,,sq #bej #beee ,,tlf 444 ,,tlf #hj #bbbbe ,,tp 444 ,,tp #dje #cccce ,,uv 444 ,,uv #aae #bce ,,xmku 444 ,,xmku #abj #bbbce ,,uv 444 ,,uv #gc ,no factors ,,yj 444 ,,yj #he #age ,! dom9ant factor is cle>ly #e1 s we may consid] t five alphabets 7 us$1 indicat+ a keyword ( five lett]s4 ,writ+ ! message 9 l9es ( five lett]s ea* & mak+ a frequ5cy table = ea* ( ! five columns s =m$1 we f9d ! foll[+3 ,frequ5cy ,tables ,colum #a ,column #b ,column #c ,column #d ,column #e ,a #aa ,a #aaaaaaaaa ,a #a ,a #a ,a #aa ,b ,b #aaa ,b #aaa ,b ,b #aaaaaaa ,c #aaaaaaa ,c #a ,c #aaa ,c #aaaa ,c ,d #aa ,d #aa ,d #a ,d ,d #aaa ,e #aaaa ,e ,e #aa ,e #aaaaaaa ,e ,f #aaa ,f ,f #aaaaaaaaa ,f #aaa ,f #aaaaa ,g #aaaaaaaaa ,g ,g #aaa ,g #aa ,g #aa ,h #aaa ,h #aaaaa ,h #aaa ,h #aaa ,h #aa ,i #aa ,i #aa ,i #aaaaaaa ,i #aaaaaaaaaaaaaaaaa ,i #aa ,j #aaaaa ,j #a ,j #aaaaaa ,j ,j #aaaaaaaaa ,k #aaaaaa ,k #aaaaa ,k ,k #a ,k #a ,l ,l #aaaaaaaaaaaaaaaaaaa ,l #aa ,l #aaaaa ,l #a ,m ,m ,m #aaaaaaa ,m #aaaa ,m #aaa ,n #aaaaaaa ,n #aaa ,n #aaaa ,n ,n #aaaaa ,o #aaaaa ,o ,o #aaaaaaaaa ,o #a ,o ,p #aaaaaaa ,p #aaaaaaa ,p #aaaaaaaa ,p #aaaa ,p ,q #aaaaa ,q ,q ,q #aa ,q #aaaaaa ,r ,r #a ,r #a ,r #aaaaaa ,r #a ,s ,s #aaaaaaaa ,s #aaaaaa ,s #aaaaaaaaaaaa ,s #aaaaaaa ,t #aaaaaaa ,t #aaa ,t #aaaaa ,t #a ,t #aaaaaaaaaaaaaa ,u #aaaaaaa ,u #aaa ,u #aaaaaa ,u ,u #a ,v #aaaaa ,v ,v #aa ,v #aaaaa ,v ,w #aaa ,w #aaaa ,w ,w #aaaaa ,w #aaaaaaa ,x #aa ,x ,x #aaaa ,x #aaaaaaaa ,x #aaaaaa ,y #aaaa ,y #aaaaa ,y ,y #aaa ,y #aaaaaaa ,z ,z #aaaaa ,z #aaa ,z ,z #aaa ,9 ! table = ,column #a1 ! lett] ,g occurs #i times4 ,let u consid] x t5tatively z ,e4 ,!n if ! ciph] alphabet runs regul>ly & 9 ! direction ( ! regul> alphabet1 ,c 7#g times7,a & ! ciph] alphabet be>s a close resemblance to ! regul> frequ5cy table4 ,note ,,tuv 7,,r/7 occurr+ respectively #g1 #g1 & #e times & ! non-occurr5ce ( ,b1 ,l1 ,m1 ,r1 ,s1 ,z1 7,z1 ,j1 ,k1 ,p1 ,q1 & ,x respectively47 ,9 ! next table1 ,l occurs #ai times & tak+ x = ,e ) ! alphabet runn+ 9 ! same way1 ,a,h4 ,! fir/ ^w ( our message1 ,,ct1 ?us becomes ,,am :5 deciph]$ ) ^! two alphabets & ! fir/ two lett]s ( ! key are ,c ,h4 ,simil>ly 9 ! ?ird table we may take ei!r ,f or ,o = ,e1 b a casual exam9ation %[s t ! =m] is correct & ,a,b 7ev5 if we 7 look+ = a v[el = ! next lett] ( ! keyword74 ,9 ! f\r? table1 ,i is cle>ly ,e & ,a,e4 ,! fif? table %[s ,t#ad & ,j#i4 ,if we take ,t,e we f9d t we w\ld h _m lett]s :i* %\ld n occur4 ,on ! o!r h&1 if we take ,j,e !n ,t,o & 9 view ( ! _m ,e's already acc\nt$ = 9 ! o!r columns1 ?is may be all "r4 ,x *ecks z correct if we apply ! la/ ?ree alphabets to ! second ^w ( our message1 ,,osb1 :i* deciph]s ,,n[4 ,us+ ^! alphabets to deciph] ! :ole message1 we f9d x to read3 ,m4 ,b4 ,am n[ safe on bo>d a b>ge moor$ bel[ ,t[] ,bridge :]e no "o w ?9k ( look+ = me4 ,h good fri5ds b little money ow+ to action ( police4 ,tru/1 little girl1 y /ill believe 9 my innoc5ce al?\gh ?+s seem aga9/ me4 ,!re are reasons :y ,i %\ld n be que/ion$4 ,%all try to emb>k be=e ! ma/ 9 "s outw>d b\nd vessel4 ,crews w n be scrut9iz$ s %>ply z pass5g]s4 ,!re are ^? :o w let y "k my movem5ts4 ,fe> ! police may tamp] ) y\r correspond5ce b lat] on :5 hue & cry h di$ d[n w let y "k all4 ,! key to ?is message is ,,*bef :i* is n intelligible z a ^w b if put into figures indicat+ t ! #b;d1 #g?1 #a/1 #d?1 & #e? lett] beyond ! correspond+ lett] ( ! message has be5 us$ ! key becomes #bgade & we may connect x ) ! p]sonal :i* appe>$ 9 ! same pap] ! day be=e read+3 ,m4 ,b4 ,w deposit #bg #ads #e;d tomorr[4 ,case #g-;b4 ,message ,,ddlrm ,,erglm ,,ujtll ,,*]s ,,lsoee ,,smeju ,,zjimu ,,daees ,,dutdb ,,gugpn ,,r*ob ,,eqeie ,,ooacd ,,eioog ,,coljl ,,pduvm ,,igiyx ,,qqtot ,,djcpj ,,oisly ,,duasi ,,upfne ,,aecob ,,oe%o ,,betnd ,,qxucy ,,luqoy ,,ehydu ,,lxpeq ,,fixze ,,pdcnz ,,enelq ,,mjtsq ,,ecfie ,,arndn ,,etscf ,,ifqse ,,tddnp ,,uuzhq ,,cdtxq ,,irm] ,,glxbe ,,iqrxj ,,fbsqd ,,ldsvi ,,xumtb ,,aeqeb ,,yleco ,,iycud ,,qtpys ,,voqbl ,,ulyro ,,yhefm ,,oymuy ,,roymu ,,eqblv ,,ubrey ,,ghytq ,,cmubr ,,eqt( ,,vsddu ,,daffs ,,cebsv ,,tioye ,,tclqx ,,dvnlq ,,xytsi ,,mzulx ,,baxqr ,,ecvtd ,,etgob ,,ccuyf ,,ttnxl ,,unefs ,,ivijr ,,zhsby ,,lltsi ,on ! prelim9>y det]m9ation1 we h ! foll[+ c\nt ( lett]s out ( a total ( #che3 ,a #h ,l #bc ,j #i ,e #ch ,n #aa ,q #bb ,i #ai ,r #ad ,v #i ,o #ba ,s #bj ,x #ac ,u #bd ,t #ba ,z #f ,total #aaj ,total #hi ,total #ei #bh #bc #ae ,e lett] except ,k & ,w occurs at lea/ six times4 ,we may say !n t x is a sub/itution ciph]1 ,spani% text1 & c]ta9ly n ,case #d1 #e or #f4 ,we w n[ analyze x = recurr+ pairs or gr\ps to det]m9e1 if x be ,case #g1 h[ _m alphabets 7 us$4 ,! foll[+ is a complete li/ ( su* recurr+ gr\ps & pairs ) ! numb] ( lett]s int]v5+ & ! factors !re(4 ,9 "w ( ?is k9d1 ! gr\ps ( ?ree or m lett]s are always mu* m valuable ?an s+le pairs4 ,= example1 ! gr\ps1 ,,hobe1 ,,oymu1 ,,rm]gl & ,,ubre %[1 )\t "q1 t six alphabets 7 us$4 ,x is n necess>y1 z a rule1 to make a complete li/ l ! foll[+3 ,,ae #gdbcg ,,ie #aajbeaa ,,re #ejbee ,,ae #abjbbbce ,,im #cjbbaea ,,rm]gl #aihbccaa ,,be #hhbbbaa ,,io #bejbeee ,,sc #acbbbcaa ,,cd #acbbbcaa ,,ix #ghbcac ,,sd #bfbbaca ,,cfi #abbbc ,,ly #aehbgi ,,si #bcjbebc ,,* #cfbbcc ,,jt #aejbcee ,,si #cdbag ,,co #dbbcg ,,ll #cfg ,no factors ,,si #bfdbbbcaa ,,co #abfbccg ,,lq #afdbbda ,,si #abbbc ,,cu #aadbcai ,,lqx #fbc ,,sl #ghbcac ,,dd #ahfbcca ,,lu #abdbbca ,,sq #edbccc ,,dd #aafbbbi ,,lu #aajbeaa ,,sv #bgccc ,,de #bheeeg ,,lu #bcdbccac ,,sv #fcccg ,,dl #bahbaji ,,lx #ffbcaa ,,sv #ijbcce ,,dn #adbg ,,lxb #acbbbcaa ,,td #dg ,no factors ,,dq #abjbbbce ,,ly #aehbgi ,,td #afeceaa ,,du #cfbbcc ,,me #bbbaa ,,td #ifbbbbbc ,,du #bdbbbc ,,mu #bdbbbc ,,tn #bci ,no factors ,,du #chbai ,,mu #bdjbbbbce ,,ts #adbg ,,du #afeceaa ,,mu #ahbcc ,,ts #aefbbcac ,,ea #cjbce ,,nd #dg ,no factors ,,tsi #ejbee ,,eb #ghbcac ,,ne #dhbbbbc ,,ubre #abbbc ,,ec #ahjbbcce ,,ne #ahbcc ,,ud #fjbbce ,,eco #abfbccg ,,ne #aibbbbbbbc ,,uda #bgjbccce ,,ees #adbg ,,ob #fbc ,,ul #aadbcai ,,ef #ajeceg ,,ob #bcdbccac ,,ulx #aihbccaa ,,ei #hbbb ,,oe #iccca ,,uy #hi ,no factors ,,ei #aebbbbai ,,oi #addbbbbcc ,,uz #afbbcccc ,,eq #hhbbbaa ,,oo #g ,no factors ,,vi #adhbbcg ,,eq #bfdbbbcaa ,,oy #fbc ,,vt #cccaa ,,eq #ddbbaa ,,oy #dfbbc ,,xq #aadbcai ,,eqe #agfbbbbaa ,,oymu #fbc ,,xq #addbbbbcc ,,er #abbbc ,,pd #gecee ,,xu #iiccaa ,,es #ghbcac ,,qbl #bdbbbc ,,ye #ahdbbbbc ,,et #acecce ,,qc #ieeai ,,yl #ajfbec ,,et #icc ,,qe #ajhbbccc ,,yl #addbbbbcc ,,et #edbccc ,,qe #fhbbag ,,ym #fbc ,,et #ca ,no factors ,,qr #acbbbcaa ,,yro #abbbc ,,he #bdeegg ,,qto #bajbceg ,,ze #fbc ,,hobe #ffbcaa ,,qx #aihbccaa ,,zh #ahccfa ,out ( "o hundr$ & "o recurr+ pairs we h fifty ) ! factors #bcf2 out ( twelve recurr+ triplets1 n9e h ^! factors2 & ! f\r recurr+ gr\ps ( f\r or m lett]s all h ^! factors4 ,! p]c5tages are respectively #di4e1 #ge & #ajj & we may be c]ta9 f ?is t six alphabets 7 us$4 ,b1 be=e ! six frequ5cy tables are made up1 !re is "o m po9t to be consid]$2 :y are !re s _m recurr+ gr\ps :i* d n h six z a factor8 ,! answ] is t "o or m ( ! alphabets is repeat$ 9 ea* cycle2 t is1 a key ^w ( ! =m ,,havana has be5 us$4 ,if ?is 7 ! key ^w1 ! second1 f\r? & six? alphabets w\ld be ! same4 ,we w see lat] t 9 ?is example ! second & six? alphabets are ! same & ?is introduces ! great numb] ( recurr+ gr\ps )\t ! factor #f4 ,we w n[ proce$ to make a frequ5cy table = ea* alphabet4 ,z ! message is writt5 9 ?irty columns1 we take ! fir/1 sev5?1 ?irte5?1 etc41 z con/itut+ ! fir/ alphabet2 ! second1 eigh?1 f\rte5?1 etc41 z con/itut+ ! second alphabet & s on4 ,! prefix & suffix lett] is not$ = ea* occurr5ce ( ea* lett]4 ,! importance ( ?is w be appreciat$ :5 ! =m ( ! frequ5cy tables is exam9$4 ,none be>s any resemblance to ! normal frequ5cy table except t ea* is evid5tly a mix$ up alphabet4 ,! numb]s aft] ,prefix & ,suffix ref] to ! alphabet to :i* ^! belong1 = conv5i5ce 9 future ref]5ce4 ,frequ5cy ,tables ,fir/ ,alphabet ,lett] ,prefix 7#f7 ,suffix 7#b7 ,a #aaa #c ,,dud ,,esf ,b #aaaaaaaa #h ,,oo(eeos ,,eoesyscy ,c #j ,d #aaaa #d ,,tyt ,,djud ,e #a #a ,e ,s ,f #j ,g #j ,h #j ,i #aaaaaaaa #h ,,e(feovs ,,osefqyj ,j #j ,l #a #a ,o ,j ,m #a #a ,f ,o ,n #aaaa #d ,,f$u ,,eeee ,o #a #a ,e ,o ,p #aa #b ,,ge ,,nd ,q #aaaa #d ,,ueoe ,,(bb ,r #aaaaaaa #g ,,eeeyybb ,,gsgooee ,s #a #a ,d ,v ,t #aaaaaaaa #h ,,jujmqyvf ,,ldsbpqdt ,u #j ,v #aa #b ,,uf ,,ms ,x #aaaaaa #f ,,yqtqqa ,,quqdyq ,y #a #a ,o ,e ,z #aaa #c ,,uum ,,jhu ,second ,alphabet ,lett] ,prefix 7#a7 ,suffix 7#c7 ,a #j ,b #aaa #c ,,tqq ,,all ,c #a #a ,b ,c ,d #aaaaaa #f ,,dtpdxt ,,lbcnve ,e #aaaaaaaaaaa #a #a ,,abnbn9rryn ,,eoatlatyqtf ,f #aaa #c ,,qia ,,iqf ,g #aa #b ,,rr ,,ll ,h #a #a ,z ,o ,i #j ,j #aaaa #d ,,zldi ,,ilcr ,l #a #a ,t ,l ,m #a #a ,v ,i ,n #a #a ,p ,r ,o #aaaaaaa #g ,,oibqrmr ,,aoeyyyy ,p #a #a ,t ,y ,q #aaaaa #e ,,xxitx ,,oircr ,r #j ,s #aaaaaaaa #h ,,reiatbvb ,,lmliqqdv ,t #a #a ,t ,n ,u #aaa #c ,,xdz ,,cll ,v #a #a ,s ,i ,x #j ,y #aaaa #d ,,bixb ,,lctl ,z #j ,?ird ,alphabet ,lett] ,prefix 7#b7 ,suffix 7#d7 ,a #aaaa #d ,,oeeb ,,c]e ,b #a #a ,d ,g ,c #aaaaaa #f ,,judyqc ,,pynumu ,d #a #a ,s ,d ,e #aaa #c ,,eod ,,s/ ,f #aa #b ,,fe ,,ss ,g #j ,h #j ,i #aaaaaa #f ,,jmsfqv ,,mguxrx ,j #j ,l #aaaaaaaaaaaaaa #ad ,,dglsjsuegybbuy ,,rmcspyxqxeuvxl ,m #a #a ,s ,e ,n #aa #b ,,dt ,,px ,o #a #a ,o ,g ,p #j ,q #aaaaaaa #g ,,eqsfhse ,,etescdt ,r #aaaa #d ,,nqqj ,,cxez ,s #j ,t #aaaa #d ,,eeey ,,nscs ,u #j ,v #aa #b ,,sd ,,tn ,x #j ,y #aaaaaa #f ,,opoooe ,,e%mmg ,z #j ,f\r? ,alphabet ,lett] ,prefix 7#c7 ,suffix 7#e7 ,a #j ,b #j ,c #aaaaa #e ,,lraqt ,,hhddl ,d #aa #b ,,qd ,,lu ,e #aaaaaaaa #h ,,mqayqalr ,,ji*cqcc ,f #j ,g #aaaa #d ,,boiy ,,ucih ,h #a #a ,y ,e ,i #j ,j #j ,l #a #a ,l ,t ,m #aaaaa #e ,,liyyc ,,uuuuu ,n #aaa #c ,,tcv ,,dzl ,o #j ,p #aaa #c ,,lcn ,,dju ,q #a #a ,l ,m ,r #aaa #c ,,lai ,,mnm ,s #aaaaaaaaa #i ,,leetqyftf ,,odhcevcii ,t #aaaa #d ,,qqve ,,ooig ,u #aaaa #d ,,iclc ,,pdly ,v #a #a ,l ,u ,x #aaaaaaa #g ,,lilriln ,,pzbubl ,y #aa #b ,,lc ,,dlj ,z #a #a ,r ,h ,fif? ,alphabet ,lett] ,prefix 7#d7 ,suffix 7#f7 ,a #j ,b #aa #b ,,xx ,,ea ,c #aaaaaaa #g ,,gddsdsd ,,o(foev ,d #aaaaaa #f ,,scpyncu ,,ueuuqtq ,e #aa #b ,,% ,,tp ,f #j ,g #a #a ,u ,t ,h #aaaaaa #f ,,ccsdgz ,,eooyys ,i #aaaaa #e ,,egtss ,,eyomv ,j #aaa #c ,,epx ,,uop ,l #aaaaaa #f ,,yducnx ,,udyqqu ,m #aaa #c ,,rqr ,,eje ,n #a #a ,r ,d ,o #aaa #c ,,/t ,,etf ,p #aa #b ,,ux ,,fe ,q #a #a ,e ,e ,r #j ,s #j ,t #a #a ,l ,s ,u #aaaaaaaaaa #aj ,,mmgpxmmvmd ,,jdgumyebbd ,v #a #a ,s ,o ,x #j ,y #a #a ,u ,f ,z #aa #b ,,xn ,,ee ,six? ,alphabet ,lett] ,prefix 7#e7 ,suffix 7#a7 ,a #a #a ,b ,x ,b #aa #b ,,uu ,,rr ,c #j ,d #aaaa #d ,,unlu ,,ansa ,e #aaaaaaaaaaaaa #ac ,,mhoidpzzmbquc ,,rreoiqpnribqb ,f #aaaaaaa #g ,,pccjeoc ,,niibmvt ,g #a #a ,u ,p ,h #j ,i #j ,j #aa #b ,,um ,,tt ,l #j ,m #aa #b ,,ui ,,tz ,n #j ,o #aaaaaaaaa #i ,,hcj*cvig ,,blibbiqyb ,p #j ,q #aaaa #d ,,ddll ,,xtxx ,r #j ,s #aa #b ,,ht ,,bi ,t #aaa #c ,,o$ ,,ddx ,u #aaaaaaa #g ,,jdddlul ,,ztvaqzn ,v #aa #b ,,ci ,,ti ,x #a #j ,i ,y #aaaaa #e ,,ihluh ,,xdrrt ,z #j ,we w n[ set d[n "s ( ! det]m9ations :i* c be made at once f ^! frequ5cy tables4 ,cle>ly sev]al mix$ alphabets h be5 us$4 ,z 0 to be expect$ f ! analysis ( ! recurr+ gr\ps1 we note t ! frequ5cy tables = alphabets #b & #f are ( s ne>ly ! same g5]al =m t c]ta9ly ^! two alphabets are "o & ! same4 ,if a ,spani% ^w has be5 us$ z a key ^w1 ?is means t ,a is probably repres5t$ by a v[el 9 ^! two alphabets & probably equals ,a or ,o1 because ^! two lett]s are su* common f9als 9 ,spani%4 #a/ ,alphabet4 ,probable v[els ,t1 ,x2 probable common consonants1 ,b1 ,i1 ,n1 ,r4 ,we conclude ?is because ( ! frequ5cy ( occurr5ce ( ,t & ,x & ! v>iety ( _! prefixes & suffixes4 ,on ! o!r h&1 ,b1 ,i1 ,n1 & ,r h = prefixes & suffixes1 9 a majority ( cases1 ,e1 ,f1 ,o & ,s :i* are ! probable v[els 9 ! #b;d & #f? alphabets4 #b;d & #f? ,alphabets4--,probable v[els ,e1 ,f1 ,o1 ,s2 probable common consonants1 ,d1 ,j1 ,q1 ,u1 ,y4 #c;d ,alphabet4--,probable v[els ,c1 ,i1 ,l2 probable common consonants ,a1 ,q1 ,t1 ,y4 #d? ,alphabet4--,probable v[els1 ,e1 ,g1 ,s1 ,t2 probable common consonants1 ,c1 ,m1 ,n1 ,p1 ,u1 ,x4 #e? ,alphabet4--,probable v[els1 ,d1 ,l1 ,u2 probable common consonants1 ,c1 ,h1 ,i4 ,n[ ?is ciph] may h be5 made up f five di/9ct alphabets ) lett]s *os5 at r&om b x is mu* m likely to h be5 prep>$ ) a ciph] disk or equival5t1 hav+ ! regul> alphabet on ! fix$ disk & ! mix$ alphabet on ! movable disk4 ,an equival5t =m ( app>atus 7n us+ ! mix$ alphabet 9 "q7 is "o l ?is3 ,fix$ ,alphabet ( ,text ,,abcdefghijlmnopqr/uvxyzabcdefghijlmnop qr/uvxyz ---------------------------------------- -------------- ,,pcjvrqzbaodfsutmxiyhlg5 ,movable ,alphabet ( ,ciph] ---------------------------------------- --- ,"h ,a ( ! pla9 text is enciph]$ by ,s & ! o!r lett]s come z !y w4 ,if we move ! ciph] alphabet "o space to ! left1 ,a w be enciph]$ by ,u & ! :ole sequ5ce ( ! alphabet w be *ang$4 ,we w !re=e use "s su* =m z ! above & see if we c ins]t our lett]s1 z !y are det]m9$1 9 su* a way z to h ea* ( ! ciph] slips id5tical4 ,we may />t ?us3 ,,abcdefghijlmnopqr/uvxyzabcdefghijlmnop qr/uvxyz #a/ ,alphabet t x #b;d ol qei ms d c u #c;d ol qei ms d c u #d? ol qei ms d c u #e? d c u ol qei ms #f? ol qei ms d c u ,9 ! #a/ alphabet1 ,t & ,x are plac$ z ,a & ,e respectively on ! basis ( frequ5cy4 ,9 ! #b;d & #f? alphabets1 ,o & ,e are plac$ z ,a & ,e respectively on ! basis ( frequ5cy4 ,9 ! #d? alphabet1 ,e & ,s are plac$ z ,a & ,e1 & 9 ! #e?1 ,d1 ,u & ,l are plac$ z ,a1 ,e & ,o = ! same reason4 ,we n[ h an excess ( ,e's & a defici5cy ( ,a's1 :i* w be correct$ if1 9 ! #c;d alphabet1 we place ,l1 ,i & ,c z ,a1 ,e & ,o respectively4 ,z a *eck1 ?is gives u ,,tol$o z ! key ^w4 ,9 ! second alphabet1 ,o is f\r lett]s to ! left ( ,e2 we may place ,o f\r lett]s to ! left ( ,e 9 ! f\r? & x comes "u ,v4 ,note t 9 ! f\r? frequ5cy table ,o 7,v7 does n occur4 ,9 ! same way 9 ! f\r? alphabet1 ,s is f\r lett]s to ! "r ( ,e2 plac+ x 9 ! same position ) respect to ,e 9 ! second & six?1 we h ,s "u ,i4 ,we h already not$ t ,s probably repres5ts a v[el 9 ^! two alphabets4 ,9 ?is way1 we may add ,d & ,u to ! ?ird alphabet f _! position 9 ! fif? ) respect to ,l & we may add ,i & ,o to ! fif? f _! position 9 ! ?ird ) respect to ,l4 ,9 e case we *eck results f ! frequ5cy tables & f9d no?+ unlikely 9 ! results4 ,n[ 9 ! second & six?1 let u try ,q1 ,d & ,u z ,d1 ,n & ,r respectively4 ,we may add ^! lett]s to ! ?ird1 f\r? & fif? alphabets by ! me?od ( obs]v+ ! numb] ( lett]s to ! "r or left ( "s lett] already fix$4 ,we n[ add ,l to ! second1 ?ird1 f\r? & six? f its position ) ref]5ce to ,d & ,u 9 ! fif?4 ,m is probably ,d 9 ! f\r? & we may add x to ea* ( ! alphabets1 except ! fir/1 9 ! same way4 ,! table is n[ complete z %[n4 ,let u try ^! lett]s on ! fir/ l9e ( ! message & see if "s o!r lett]s w be self-evid5t4 ,alphabet #a #b #c #d #e #f #a #b #c #d #e #f #a #b #c #d #e #f #a #b #c #d #e #f #a #b #c #d #e #f ,message ,d ,d ,l ,r ,m ,e ,r ,g ,l ,m ,u ,j ,t ,l ,l ,c ,h ,e ,r ,s ,l ,s ,o ,e ,e ,s ,m ,e ,j ,u ,deciph]$ ,n ,a ,u ,e ,a ,d ,e ,a ,b ,a ,l ,e ,i ,a ,e ,n ,e ,i ,g ,a ,r ,ref]r+ to our frequ5cy tables z a *eck on suppositions1 we f9d ev]y?+ agrees well en\gh if we assume ! fir/ l9e to read3 ,,unafu]za ,,de ,,caball]ia ,,enemiga ,we w n[ put ! newly f\nd lett]s 9 ! table4 ,! lett]s previ\sly f\nd are 9 capitals & ! new lett]s 9 small lett]s4 ,! addition ( ,d 7,u7 to ! fir/ alphabet p]mits u to add all ! lett]s ( ! o!r alphabets to ! fir/ by ! me?ods already discuss$4 ,ea* ( ! o!r lett]s may !n be add$ to e alphabet by ^! me?ods3 ,,abcdefghijlmnopqr/uvxyzabcdefghijlmnop qr/uvxyz #a/ ,t xhgoljqei msr d c u #b;d t xhg,o,lj,q,e,i ,m,sr ,d ,c ,u #c;d t xhg,o,lj,q,e,i ,m,sr ,d ,c ,u #d? t xhg,o,lj,q,e,i ,m,sr ,d ,c ,u #e? t xhg,o,lj,q,e,i ,m,sr ,d ,c ,u #f? t xhg,o,lj,q,e,i ,m,sr ,d ,c ,u ,"o alphabet *ecks ano!r 9 ?is way & we f9d ev]y?+ to fit s f>4 ,we w deciph] a few words m ( ! ciph] message by ! above alphabets & see if we c det]m9e "s new lett]s4 ,alphabet #efabcdefabcdefabcdefabcdefabcdefabcdefa bcdefabcdefabcdefab ,message ,,juzjimudaeesdutdbgugpnr*obeqeieooacdei oogcoljlpduvmigiyxq ,deciph]$ ,,pr,,c$5,,ede>au,,uez,,illa,,ecaseha,,l a5azucaica,,ar,,heus,,ed ,aga9 ref]r+ to ! frequ5cy tables ! fir/ ^w is evid5tly ,,proc$5te4 ,we h also ,,halla & ,,m>*eu/$4 ,! lett] ,b may be det]m9$ f ano!r ciph] gr\p1 ,,jfbsqdld 7#efabcdef7 ,,posicion4 ,! lett] ,n may be det]m9$ f ,,betndqxuc 7#abcdefabc7 ,,s]rad]o4 ,! lett]s ,f & ,y may be det]m9$ f ,,jcpjoislyduasiupf 7#bcdefabcdefabcdef7 ,,compania ,,p>ti5do4 ,! complet$ alphabets1 arrang$ z be=e1 are3 ,,abcdefghijlmnopqr/uvxyzabcdefghijlmnop qr/uvxyz #a/ ,,tyvnxhgoljqeizmsrbadfcpu #b;d ,,tyvnxhgoljqeizmsrbadfcpu #c;d ,,tyvnxhgoljqeizmsrbadfcpu #d? ,,tyvnxhgoljqeizmsrbadfcpu #e? ,,tyvnxhgoljqeizmsrbadfcpu #f? ,,tyvnxhgoljqeizmsrbadfcpu ,! key ^w is ,,tol$o & ! completely deciph]$ message is3 ,una fu]za de caball]ia enemiga proc$5te de ,aranjuez y ,villaseca se halla en ,azucaica4 ,m>*e u/$ con su compania p>ti5do de la casa de la s]rad]o por las alturas de lo e/e y norte de ,azucaica con el f9 de reconoc] su num]o y clase de fu]zas y en disposicion que se halla4 7,q7 ,e/a acantonada 7,q7 ,se hallan otras tropas detras de ella 7,q74 ,el resultado del reconocimi5to necesito sab]lo d5tro de tres horas y m$ia cu&o mas4 ,pongo a sus ord5es un cicli/a 7,x7 ,f94 ,special ,solution = ,case #g ,:5 a %ort message is enciph]$ ) a long key ^w1 ! me?ods ( analysis already discuss$ may fail2 fir/1 because !re w be no recurr+ pairs to indicate ! numb] ( alphabets us$ &1 second1 because !re w be s few lett]s 9 ea* alphabet t ! me?ods ( ,case #f w n be easily appli$4 ,h[ev]1 if we "k or correctly assume "o ^w1 pref]ably a fairly long "o1 9 ! ciph] text1 a solution is v simple4 ,= example1 ! foll[+ message is believ$ to ref] to ren=cem5ts & to conta9 t ^w4 ,,yanzv ,,znlpp ,,kqfxi ,,jbpwa ,,nruqp ,,eplom ,,cc:m ,i ,let u assume t ,,re9=cem5ts is ! fir/ ^w & t x is repres5t$ by ! ciph] gr\p ,,yanzvznlppkqfx4 ,we may put ! te/ 9 ?is tabul> =m1 us+ a ciph] disk & a ,l>rabee ciph] c>d to det]m9e ! value ( ,a = ea* lett] "u ^! two sy/ems4 ,any o!r alphabets suspect$ may be tri$ out at ! same "t4 ,if ,y ,a ,n ,z ,v ,z ,n ,l ,p ,p ,k ,q ,f ,x equals ,r ,e ,i ,n ,f ,o ,r ,c ,e ,m ,e ,n ,t ,s !n1 ) ciph] disk1 ,a equals ,p ,e ,r ,m ,a ,n ,e ,n ,t ,b ,o ,d ,y ,p &1 9 ,vig5]e ciph]1 ,a equals ,h ,w ,f ,m ,q ,l ,w ,j ,l ,d ,g ,d ,m ,f ,x is evid5t t ! guess z to ! appe>ance ( ! ^w ,,re9=cem5ts 0 correct1 t x is ! fir/ ^w ( ! message1 t ! ciph] disk 0 us$ 9 prep>+ ! ciph] & t ! key words are ,,p]man5t ,,body4 ,?is is1 ( c\rse1 an especially favorable case & we w take "o less favorable to %[ h[ ?is me?od c be appli$4 ,two ,mexican *iefta9s1 ,a & ,b1 h be5 communicat+ ) ! foll[+ ciph] alphabet3 ,pla9 text ,,abcdefghijlmnopqr/uvxyz ,ciph] ,,pcjvrqzbaodfsutmxiyhlg5 ,?is alphabet has be5 det]m9$ f _m radio messages f ,a1 ! sup]ior1 to ,b1 8 sub-ord9ate1 :o has a =ce ( ab\t #b1jjj m5 ne> ! bord]4 ,a uses ! =m ,,ord5o ,,que in/ead ( ! m famili> ,,m&o ,,que 9 all 8 messages giv+ ord]s to ,b4 ,! foll[+ message is receiv$ f ,a by ,b's radio /ation 7& o!r li/5+ /ations7 & ab\t an h\r lat] !re is a good deal ( noise & movem5t z if ,b's =ce 7 break+ camp4 ,,iihah ,,ydxrp ,,egqgv ,,jjeee ,,hobgv ,,gjcag ,,xaesa ,,vvxle ,,iilhm ,,psqag ,,bdgav ,,gsqaz ,?is is a sub/itution ciph]1 b x is n ,case #f us+ ! usual alphabet ( ! communications f ,a to ,b &1 9 fact1 is n ,case #f at all4 ,! recurr+ pairs & triplets po9t to a key ^w ( t5 lett]s & ?is w\ld give u b six lett]s p] alphabet if x is ,case #g4 ,! prep>ations = a move lead u to believe t ,a has giv5 an ord] to ,b & he has1 9 t case1 probably us$ ! expression ,,ord5o ,,que 9 ! message4 ,we w try ! fir/ n9e lett]s ( ! message z 9 ! o!r example1 fir/ prep>+ a ciph] disk or equival5t slid+ arrangem5t hav+ on x ! alphabet usually us$ betwe5 ^! *iefta9s or ,a-,b ciph]4 ,fix$ ,ciph] ,alphabet ,,pcjvrqzbaodfsutmxiyhlg5pcjvrqzbaodfsut mxiyhlg5 ---------------------------------------- -------------- ,,abcdefghijlmnopqr/uvxyz ,slid+ ,pla9 ,text ,alphabet ---------------------------------------- -- ,a-,b ,ciph] ,if ,i equals ,o !n ,a equals ,r ,i ,r ,c ,h ,d ,x ,a ,e ,r ,h ,n ,b ,y ,o ,q ,cle>ly !re is no?+ "h & ! assum$ words1 if !y occur1 are 9 ! middle ( ! message4 ,we may jump to ! comb9ation ,,pegqgv at once s9ce ! prec$+ lett]s d n make ,,ord5o ,,que4 ,we try ?is )\t result & proce$ to ,,egqgvj1 ,,gqgvjj1 ,,qgvjje1 ,,gvjjee1 ,,vjjeee1 ,,jjeeeh1 ,,jeeeho1 ,,eeehob1 ,,eehobg1 ,,ehobgv1 ,,hobgvg1 ,,obgvgj1 ,,bgvgjc1 ,,gvgjca1 ,,vgjcag1 all )\t result4 ,?is "w requires less "t ?an might be imag9$ & is ! k9d ( "w :i* c be divid$ among a numb] ( op]ators4 ,n[ let u come to ! next comb9ation ,,gjcagx4 ,we add ! next ?ree lett]s1 ,,aes1 aga9/ ,,que4 ,if ,g ,j ,c ,a ,g ,x ,a ,e ,s equals ,o ,r ,d ,e ,n ,o ,q ,u ,e ,!n1 9 ! ,a-,b ciph]1 ,a equals ,a ,d ,e ,r ,o ,v ,i ,v ,a ,! key is f\nd2 ,,viva,,ad]o & a trial ( ,m 9 ! blank space %[s correct results4 ,?is *ecks ) our !ory t a t5 lett] key ^w 0 us$ & deciph]+ ! message we h3 ,,p>a ,,el ,,ataque ,,contra ,,torreon ,,ord5o ,,que ,,sus ,,tropas ,,m>*5 ,,e/e ,,no*e ,x4 ,! reason = break+ camp is n[ evid5t4 ,?is me?od may be us$1 ) "s labor1 on %ort words l ,,!1 ,,&1 etc4 ,p>ts ( ! key w appe> :5ev] an assum$ ^w is f\nd 9 ! message & ! :ole key may be assembl$ if en\gh ( ! p>ts are available4 ,ev5 if only "p ( ! key may be s recov]$1 x w always lead to ! ultimate solution ( ! ciph] by trial ( ! p>tially recov]$ key on ! message lett] by lett]4 ,z an example ( recov]y ( a key by use ( %ort common words1 let u ref] to ! message ( ,case #g-;a4 ,!re are tw5ty-f\r gr\ps ( ?ree lett]s ea* 9 ?is message & we w try !m aga9/ ,,!1 ,,are & ,,y1 assum+ t ! ,vig5]e ciph] is us$4 #a #b #c #d #e #f #g #h #i #aj #aa #ab ,if ,,osb ,,voi ,,gsw ,,cyy ,,zsz ,,bvj ,,xld ,,osy ,,uvd ,,yjl ,,sqa ,,hsi equals ,,! ,,! ,,! ,,! ,,! ,,! ,,! ,,! ,,! ,,! ,,! ,,! or ,,are ,,are ,,are ,,are ,,are ,,are ,,are ,,are ,,are ,,are ,,are ,,are or ,,y ,,y ,,y ,,y ,,y ,,y ,,y ,,y ,,y ,,y ,,y ,,y !n ,a equals ,,vlx ,,*e ,,nls ,,jru ,,glv ,,i( ,,eez ,,vlu ,,boz ,,f* ,,zjw ,,ole or ,,obx ,,vxe ,,gbs ,,*u ,,zbv ,,bef ,,xuz ,,obu ,,uez ,,y% ,,szw ,,hbe or ,,qeh ,,xao ,,iec ,,eke ,,bef ,,dhp ,,zxj ,,qee ,,:j ,,avr ,,ucg ,,jeo #ac #ad #ae #af #ag #ah #ai #bj #ba #bb #bc #bd ,if ,,bjv ,,sfx ,,dqb ,,aii ,,ohz ,,ivx ,,jbf ,,esf ,,jsc ,,nlu ,,ctw ,,csm equals ,,! ,,! ,,! ,,! ,,! ,,! ,,! ,,! ,,! ,,! ,,! ,,! or ,,are ,,are ,,are ,,are ,,are ,,are ,,are ,,are ,,are ,,are ,,are ,,are or ,,y ,,y ,,y ,,y ,,y ,,y ,,y ,,y ,,y ,,y ,,y ,,y !n ,a equals ,,icr ,,zyt ,,kjx ,,hbe ,,vav ,,pot ,,qub ,,llb ,,qly ,,ueq ,,jms ,,jli or ,,bsr ,,sot ,,dzx ,,are ,,oqv ,,iet ,,jkb ,,ebb ,,jby ,,nuq ,,ccs ,,cbi or ,,dvb ,,urd ,,f* ,,yuo ,,qtf ,,khd ,,lnl ,,gel ,,lei ,,pxa ,,efc ,,ees ,9 column #e1 we h1 = ,,y1 ! key ,,bef2 column #f gives ! same key = ,,are2 column #aj gives ! key ,,f* = ,,! & column #ae gives ! same key = ,,y2 column #ab gives ! key ,,hbe = ,,are & column #af gives ! same key = ,,!2 column #bc gives ! key ,,efc = ,,y4 ,! only possible key = ! message is a five-lett] "o made up ( ! lett]s ,,bef* or ,,ef*b or ,,f*be or ,,*bef or ,,hbefc4 ,if ! key 9 ?is case 7 a ^w1 we w\ld h no difficulty 9 det]m9+ x2 z x is1 !re is no real difficulty 9 ! matt] z we may n[ divide ! message into blocks ( five lett]s & note t ,,zsz 7,,y7 =m ! #c;d1 #d? & #e? lett]s ( a gr\p4 ,! correspond+ key lett]s1 ,,bef1 are !n ! #c;d1 #d? & #e? lett]s ( ! key :i* mu/ be ,,*bef4 ,?is special solution = ,case #g dep5ds s l>gely on ! intuition ( ! op]ator 9 *oice ( a ^w t x is n1 9 g5]al1 advisable to use x unless ! message is v %ort & ! regul> me?ods ( analysis h be5 tri$ unsuccessfully4 ,x is1 h[ev]1 a wond]fully %ort cut 9 difficult cases :]e ! o!r me?ods fail4 ,,*apt] ,,viii ,case #h4 ,! ,playfair ciph]4 ,?is is ! ,engli% milit>y field ciph]2 z ! me?od is publi%$ 9 ,engli% milit>y manuals & z x is a ciph] ( prov5 reliability1 x may be met ) 9 g5]al ciph] "w4 ,! ,playfair ciph] op]ates ) a key ^w2 two lett]s are sub/itut$ = ea* two lett]s ( ! text4 ,! ,playfair ciph] may be recogniz$ by ! foll[+ po9ts3 7a7 ,x is a sub/itution ciph]1 7b7 x always conta9s an ev5 numb] ( lett]s1 7c7 :5 ! ciph] is divid$ into gr\ps ( two lett]s ea*1 no gr\p consi/s ( ! repetition ( ! same lett] z ,,ss or ,,bb1 7d7 !re w be recurr5ce ( pairs ?r\gh\t ! message1 foll[+ 9 a g5]al way1 ! frequ5cy table ( digraphs ( pairs1 7e7 9 %ort messages !re may be recurr5ce ( ciph] gr\ps repres5t+ words or ev5 phrases1 & ^! w always be f\nd 9 long messages4 ,9 prep>+ a ciph] by ?is me?od1 a key ^w is *os5 by ! correspond5ts4 ,a l>ge squ>e1 divid$ into tw5ty-five small] squ>es1 is con/ruct$ z %[n bel[ & ! lett]s ( ! key ^w are writt5 91 beg9n+ at ! upp] left h& corn]4 ,if any lett] recurs 9 ! key ^w1 x is only us$ on ! fir/ occurr5ce4 ,! rema9+ lett]s ( ! alphabet are us$ to fill up ! squ>e4 ,x is cu/om>y to consid] ,i & ,j z "o lett] 9 ?is ciph] & !y are writt5 toge!r 9 ! same squ>e4 ,if ! key ^w *os5 is ,,leav5wor?1 !n ! squ>e w\ld be con/ruct$ z foll[s3 ,l ,e ,a ,v ,n ,w ,o ,r ,t ,h ,b ,c ,d ,f ,g ,,ij ,k ,m ,p ,q ,s ,u ,x ,y ,z ,! text ( ! message to be s5t is !n divid$ up into gr\ps ( two lett]s ea*1 & equival5ts are f\nd = ea* pair4 ,e pair ( lett]s 9 ! squ>e mu/ be3 ,ei!r 7#a7 9 ! same v]tical l9e4 ,?us 9 ! above example ea* lett] is repres5t$ 9 ciph] by t :i* /&s next bel[ x1 & ! bottom lett] by ! top "o ( ! same column2 = in/ance1 ,,ty is repres5t$ by ,,fv4 ,or 7#b7 9 ! same horizontal l9e4 ,ea* lett] 9 ?is case is repres5t$ by t :i* /&s next on its "r1 & ! lett] on ! extreme "r by t on ! extreme left ( ! same horizontal l9e ) x2 = in/ance ,,rh is repres5t$ by ,,tw4 ,or 7#c7 at opposite corn]s ( a rectangle4 ,ea* lett] ( ! pair is repres5t$ by ! lett] 9 ! o!r corn] ( ! rectangle 9 ! same horizontal l9e ) x2 = in/ance ,,ts is repres5t$ by ,,wy4 ,if1 on divid+ ! lett]s ( ! text into pairs1 x is f\nd t a pair consi/s ( ! same lett] repeat$1 a dummy lett]1 z ,x1 ,y1 or ,z1 %\ld be introduc$ to sep>ate ! simil> lett]s4 ,if ! message to be s5t 7 ,! enemy moves at dawn1 x w\ld be divid$ into pairs3 ,,? ,,ex ,,en ,,em ,,ym ,,ov ,,es ,,at ,,da ,,wn & enciph]$3 ,,hw ,,au ,,al ,,ak ,,xp ,,te ,,lu ,,vr ,,mr ,,hl ,! message is !n brok5 up into gr\ps ( five lett]s = transmission4 ,to deciph] su* a cryptogram1 7kn[+ ! key ^w71 ! receiv] divides x into pairs1 & f 8 table f9ds ! equival5t ( ^! pairs1 tak+ ! lett] imm$iately above ea*1 :5 !y are 9 ! same v]tical l9e2 ^? imm$iately on ! left1 :5 9 ! same horizontal l9e2 & ^? at opposite angles ( ! rectangle :5 ?is is =m$4 ,x is evid5t1 f ! =ego+ description1 t any lett] ( ! pla9 text may be repres5t$ 9 ciph] by "o ( five lett]s1 viz3 ,! "o next bel[ x & ! o!r f\r lett]s 9 ! same horizontal l9e ) x 9 ! squ>e4 ,take1 = example1 ! lett] ,d ( ! pla9 text1 9 comb9ation ) ea* ( ! o!r lett]s ( ! alphabet4 ,we h1 us+ ! key ,,leav5wor?3 ,,da ,,db ,,dc ,,de ,,df ,,dg ,,dh ,,di ,,dk ,,dl ,,dm ,,dn ,,d ,,dp ,,dq ,,dr ,,ds ,,dt ,,du ,,dv ,,dw ,,dx ,,dy ,,dz ,,mr ,,fc ,,fd ,,ca ,,fg ,,fb ,,gr ,,bm ,,cm ,,ba ,,mx ,,ga ,,cr ,,fm ,,gm ,,md ,,bx ,,fr ,,cx ,,fa ,,br ,,ma ,,fx ,,gx ,?is gives ,d repres5t$ by ,b ,c ,f ,g ,m #d #d #h #d #d times1 &1 connect$ ) ^! five lett]s repres5t+ ,d1 we h ,a ,r ,d ,m ,x ,b ,c ,g #e #e #b #d #e #a #a #a times4 ,note t ^! lett]s are ^? ( ! v]tical column conta9+ ,d plus ! lett]s ,b1 ,c & ,g1 ( ! horizontal l9e conta9+ ,d4 ,lieut4 ,frank ,moorman1 ,u4 ,s4 ,army1 has develop$ a me?od = det]m9+ ! lett]s :i* make up ! key ^w 9 a ,playfair ciph]4 ,9 ! fir/ place1 a key ^w necess>ily conta9s v[els 9 ! approximate proportion ( two v[els to ?ree consonants & x is also likely t a key ^w w conta9 o!r common lett]s4 ,?is key ^w is plac$ 9 ! fir/ r[ or r[s4 ,n[ if a table is made1 %[+ :at lett]s 9 ! ciph] occur ) e lett]1 x w be f\nd t ! lett]s hav+ ! greate/ numb] ( o!r lett]s 9 comb9ation ) !m are v likely to be lett]s ( ! key ^w1 or 9 o!r words1 lett]s occurr+ 9 ! fir/ or second l9es4 ,an example w make ?is cle>3 ,message ,,db ,,fn ,,ex ,,tz ,,mf ,,to ,,vb ,,qb ,,qt ,,ob ,,xa ,,( ,,pr ,,tz ,,eq ,,rh ,,qk ,,qv ,,dx ,,ok ,,ab ,,pr ,,qi ,,el ,,tv ,,ke ,,ex ,,xs ,,fs ,,bp ,,wd ,,bo ,,by ,,bf ,,ro ,,ea ,,bo ,,rh ,,qk ,,qv ,,tx ,,gu ,,el ,,ab ,,? ,,tr ,,xn ,,on ,,ea ,,ay ,,xh ,,bo ,,hn ,,ex ,,bs ,,hr ,,qb ,,zm ,,se ,,xp ,,hf ,,gz ,,ug ,,kc ,,bd ,,po ,,ea ,,ay ,,xh ,,bo ,,xp ,,hf ,,kr ,,qi ,,ab ,,pr ,,qi ,,el ,,bx ,,fz ,,bi ,,se ,,fx ,,pb ,,ra ,,pr ,,qi ,,wc ,,br ,,xd ,,yg ,,tb ,,qt ,,ea ,,ay ,,xh ,,bo ,,hn ,,ex ,,bs ,,hr ,,qb ,,pr ,,qi ,,el ,,bx ,,bt ,,hb ,,qb ,,nf ,,si ,,se ,,bx ,,nu ,,xp ,,bu ,,rb ,,xb ,,qr ,,ox ,,ba ,,tb ,,rh ,,bp ,,wd ,,rp ,,ro ,,gu ,,gx ,,qr ,,se ,,zy ,,ox ,,ba ,,el ,,ax ,,cw ,,by ,,ba ,,sx ,,rk ,,ro ,,pr ,,hb ,,op ,,bd ,,pi ,,cn ,,ox ,,em ,,rp ,,kr ,,xt ,,el ,,ax ,,cw ,,eq ,,fz ,,sx ,,el ,,rh ,,ro ,,pr ,,hb ,,ux ,,da ,,se ,,xn ,,zn ,,gu ,,el ,,bx ,,fs ,,dg ,,db ,,tb ,,zl ,,ve ,,rh ,,bo ,,rq4 ,f ?is message1 we make up ! foll[+ table1 consid]+ ! lett]s ( ea* pair3 ,fir/ ,lett]s ( ,pairs ,a ,b ,c ,d ,e ,f ,g ,h ,i ,k ,l ,m ,n ,o ,p ,q ,r ,s ,t ,u ,v ,w ,x ,y ,z ,a #c #a #d #a #a ,b #c #b #c #a #a #d #a #c #a #a ,c #a #a ,d #b #b #a ,e #a #e #a ,f #a #b #a #a #a ,g #a #a #a #a ,h #e #a #c ,i #a #a #e #a ,k #a #b #a ,l #h #a ,m #a #a ,n #a #a #b #a #b #a ,o #f #a #d #a ,p #b #a #b #c ,q #b ,r #a #b #b #g #b #a ,s #b #b #a ,t #a #b #a ,u #a #c #a ,v #b ,w #b ,x #a #e #a #d #a #a #c #b #a #a ,y #e #a ,z #b #a #b ,f ?is table we pick out ! lett]s ,b1 ,e1 ,f1 ,o1 ,r1 ,t1 ,x1 z t5tative lett]s ( ! key ^w on acc\nt ( ! v>iety ( o!r lett]s ) :i* !y occur4 ,z !re are b two v[els = sev5 lett]s1 we w add ,a to ! li/ on acc\nt ( its occurr5ces ) ,b1 ,d1 ,e1 ,r1 & ,x4 ,?is leaves ! lett]s = ! bottom l9es ( ! squ>e z foll[s3 -------------------- 4 4 4 4 4 -------------------- 4 4 4 ,c ,d -------------------- ,g ,h ,,ij ,k ,l -------------------- ,m ,n ,p ,q ,s -------------------- ,u ,v ,w ,y ,z -------------------- ,ref]r+ to ! table aga9 we f9d ! mo/ frequ5t comb9ation to be ,,el1 occurr+ #h times1 ) no occurr5ce ( ,,le4 ,n[1 ,,? is ! commone/ pair 9 pla9 text1 & ,,ht is n common4 ,! fact t ,h occurs 9 ! same horizontal l9e ) ,l & t ,e & ,t are probably 9 ! key1 w lead u to put ,e 9 ! fir/ l9e ov] ,h & ,t 9 ! fir/ l9e ov] ,l1 s z to make ,,el equal ,,?4 ,! next mo/ frequ5t comb9ation is ,,pr occurr+ #g times1 ) ,,rp occurr+ twice4 ,9 ! squ>e z p>tially arrang$1 ,,pr equals ,m or ,n or ,q or ,i4 ,we may elim9ate all ^! except ,n1 & ?is ,n c\ld only be ,,no or ,,na1 s t we w put1 t5tatively ! ,r 9 ! second l9e ov] ,h & ! ,o & ,a 9 ! same l9e ov] ,,ij4 ,we h !n3 -------------------- 4 ,e 4 4 ,t -------------------- 4 ,r ,,ao ,c ,d -------------------- ,g ,h ,,ij ,k ,l -------------------- ,m ,n ,p ,q ,s -------------------- ,u ,v ,w ,y ,z -------------------- ,let u n[ *eck ?is by pick+ out ! comb9ations beg9n+ ) ,,el & see+ if ! table w solve !m4 ,we f9d1 ,,eltv1 ,,elab1 ,,elbxfz1 ,,elbxbt1 ,,elaxcwby1 ,,elaxcweq1 ,,elrh1 ,,elbxfs4 ,n[1 on ! assumption t ! lett] aft] ,,el repres5ts ,e1 we h x repres5t$ by ,a ?ree times1 ,b ?ree times1 ,r once & ,t once4 ,?is requires t ,a & ,b be put 9 ! same horizontal l9e ) ,e1 s9ce ,t is already !re1 & ,r is t5tatively "u ,e4 ,! comb9ation ,,eltv n[ equals ,,!z4 ,if ! ,t 7 mov$ "o place to ! left1 x w\ld be ,,!y1 a m likely comb9ation1 b ?is requires ! ,l to be mov$ "o place to ! left also1 by putt+ ,i or ,k 9 ! key ^w & tak+ out ,o1 ,r or ,x & return+ x to its place 9 ! alphabetical sequ5ce4 ,! mo/ frequ5t pairs conta9+ ,o are ,b ,o six times1 ,r ,o f\r times1 & ,o ,x ?ree times4 ,n[ ^! pairs equal respectively ,e ,n1 ,e ,s & ,h ,e1 if ,o is put betwe5 ,n & ,p 9 ! f\r? l9e4 ,we w !re=e cease to consid] x z a lett] ( ! ! key ^w4 ,! comb9ation ,,elab c only be ,,! on ! assumption t ,a is ! fir/ lett] to ! "r ( ,e4 ,! comb9ation ,,elbx occurs ?ree times4 ,if x repres5ts ,,!1 ! ,b mu/ be ! fir/ lett] ( ! fir/ l9e & ! ,x mu/ n[ be plac$ "u ,e :]e ! ,r 0 t5tatively put4 ,we c get ,,! out ( ,,elrh by putt+ ,r 9 ! fir/ l9e or leav+ x :]e x is1 b ! prepond]ance ( ! ,,bx comb9ation %\ld sugge/ ! =m] alt]native4 ,a new squ>e %[+ ^! *anges w look l ?is3 -------------------- ,b ,e ,a ,t ,r -------------------- 4 ,x 4 4 4 -------------------- ,g ,h 4 ,l ,m -------------------- ,n ,o ,p ,q ,s -------------------- ,u ,v ,w ,y ,z -------------------- ,z ,i put 9 ! space "u ,b w give ! ^w ,,beatrix & z a v[el is cle>ly necess>y !re1 we w s use ! ,,ij & leave ,k betwe5 ,h & ,l4 ,?is leaves ,c1 ,d & ,f to be plac$4 ,x appe>$ at fir/ t ,f 0 9 ! key b if x is 9 ! second l9e1 9 proximity to ! lett]s ( ! fir/ l9e1 x w give ! same indications4 ,complet+ ! squ>e !n1 we h -------------------- ,b ,e ,a ,t ,r -------------------- ,,ij ,x ,c ,d ,f -------------------- ,g ,h ,k ,l ,m -------------------- ,n ,o ,p ,q ,s -------------------- ,u ,v ,w ,y ,z -------------------- ,) ?is squ>e1 ! message is deciph]$ )\t difficulty4 ,x is v frequ5tly neces7x7s>y to employ ciph]s & !y h = _m c5turies be5 employ$ 9 ! relations betwe7x7en gov]nm5ts1 = com7x7munication betwe7x7en com7x7m&]s & _! subord9ates & p>ticul>ly betwe7x7en gov]nm5ts & _! ag5ts 9 =eign c\ntries2 !re are _m cases 9 hi/ory :]e ! capture ( a message n 9 ciph] has made ! captors ( ! message victori\s 9 _! milit>y movem5ts4 ,x w be se5 t ! me?od ( ,lieut4 ,moorman enabl$ u to pick out six lett]s ( ! key ^w out ( eight lett]s *os5 t5tatively4 ,! reason = ! appe>ance ( ,f has already be5 not$2 ! lett] ,o occurr$ ) _m o!r lett]s because x happ5$ to rema9 9 ! same l9e ) ,n & ,s & to be "u ,h4 ,x ?us 0 likely to repres5t any ( ^! ?ree lett]s :i* occur v frequ5tly 9 any text4 ,two-"* ,sub/itution ,ciph]s ,case #i4--,two-"* sub/itution ciph]s4 ,9 ciph]s ( ?is type1 two lett]s1 num]als1 or conv5tional signs1 are sub/itut$ = ea* lett] ( ! text4 ,!re are _m ways ( obta9+ ! *>act]s to be sub/itut$ b1 9 g5]al1 ^! ciph]s may be consid]$ z special v>ieties ( ,case #f or ,case #g4 ,! ciph]s :i* come "u ?is case are n well suit$ to telegraphic correspond5ce because ! ciph] message w conta9 twice z _m lett]s z ! pla9 text4 ,h[ev] !y are s us$2 an example is at h& 9 :i* two num]als are sub/itut$ = ea* lett] & ?is makes transmission by telegraph v sl[4 ,case #i c be recogniz$ by "s or all ( ! foll[+ po9ts2 ! numb] ( *>act]s 9 ! ciph] is always an ev5 numb]2 (t5 only a few1 say five to t51 ( ! lett]s ( ! alphabet appe>2 ei!r a frequ5cy table = pairs ( ! ciph] text resembl+ ! normal s+le lett] frequ5cy table c be made1 or gr\ps ( f\r lett]s w %[ a regul> recurr5ce1 f :i* ! ciph] c be solv$ z 9 ,case #g4 ,case #i;a4-- ,message ,,rntgn ,,raagr ,,n>na ,,gtgra ,,tgaan ,,nangg ,,r>at ,,naanr ,,nnnrn ,,aaagg ,,aangr ,,nggnn ,,nrnaa ,,aanra ,,tnann ,,nggrn ,,rnnrg ,,ttgrg ,,tggrn ,,arntg ,,nn>t ,,ggrnr ,,grnnt ,,gtgaa ,,nn>n ,,arnrt ,,tgagg ,,gaaaa ,,nanna ,,rnaga ,,ngnat ,,nnnat ,?is message conta9s #afj lett]s & x w be not$ t ! only lett]s us$ are ,a1 ,g1 ,n1 ,r & ,t4 ,we may expect a simple two-lett] sub/itution ciph] at once4 ,x w simplify ! "w if we divide ! ciph] into gr\ps ( two lett]s & !n1 if we f9d !re are #bf or less recurr+ gr\ps1 to assign an arbitr>y lett] to ea* gr\p & "w out ! ciph] by ! me?od ( ,case #f4 ,,rn ,,tg ,,nr ,,aa ,,gr ,,na ,,rn ,,ag ,,tg ,,ra ,,tg ,,aa ,,nn ,,an ,,gg ,,ra ,,ra ,,tn ,,aa ,,nr ,,nn ,,nr ,,na ,,aa ,,gg ,,aa ,,ng ,,rn ,,gg ,,nn ,,nr ,,na ,,aa ,,an ,,ra ,,tn ,,an ,,nn ,,gg ,,rn ,,rn ,,nr ,,gt ,,tg ,,rg ,,tg ,,gr ,,na ,,rn ,,tg ,,nn ,,ar ,,tg ,,gr ,,nr ,,gr ,,nn ,,tg ,,tg ,,aa ,,nn ,,ar ,,na ,,rn ,,rt ,,tg ,,ag ,,gg ,,aa ,,aa ,,na ,,nn ,,ar ,,na ,,ga ,,ng ,,na ,,tn ,,nn ,,at ,) arbitr>y lett]s sub/itut$1 we h ,a ,b ,c ,d ,e ,f ,a ,g ,b ,h ,b ,d ,i ,j ,k ,h ,h ,l ,d ,c ,i ,c ,f ,d ,k ,d ,m ,a ,k ,i ,c ,f ,d ,j ,h ,l ,j ,i ,k ,a ,a ,c ,n ,b ,o ,b ,e ,f ,a ,b ,i ,p ,b ,e ,c ,e ,b ,b ,d ,i ,p ,f ,a ,q ,b ,g ,k ,d ,d ,f ,i ,p ,f ,r ,m ,f ,l ,i ,s ,n[1 prep>+ a frequ5cy table1 ) note ( prefixes & suffixes we h3 ,frequ5cy ,prefix ,suffix ,a #g #aaaaaaa ,,fmkaff ,,bgkacbq ,b #aj #aaaaaaaaaa ,,aghnoapibq ,,*doeiebdg ,c #f #aaaaaa ,,bdiiae ,,diffne ,d #i #aaaaaaaaa ,,cblfkfbkd ,,eickmjidf ,e #d #aaaa ,,dbbc ,,ffci ,f #h #aaaaaaaa ,,eccepdpm ,,addaairl ,g #b #aa ,,ab ,,bk ,h #d #aaaa ,,bkjh ,,bhll ,i #i #aaaaaaaaa ,,dckjb$fl ,,jcckpbpp ,j #c #aaa ,,idl ,,khi ,k #e #aaaaa ,,jdaig ,,hdiad ,l #c #aaa ,,hhf ,,dji ,m #b #aa ,,dr ,,af ,n #a #a ,c ,b ,o #a #a ,b ,b ,p #c #aaa ,,iii ,,bff ,q #a #a ,a ,b ,r #a #a ,f ,m ,s #a #a ,i ,a brief /udy ( ?is table & ! di/ribution 9 ! ciph] leads to ! conclusion t ,b1 ,f & ,c are c]ta9ly v[els & are1 if ! normal frequ5cy holds1 equal to ,e1 ,o1 & ,a or ,i4 ,simil>ly ,d & ,i are consonants & we may take !m z ,n & ,t4 ,i is tak5 z ,t because ( ! comb9ation ,,ip 7possibly ,,?7 occurr+ ?ree times4 ,! next lett] 9 ord] ( frequ5cy is ,a2 x is c]ta9ly a consonant & may be tak5 z ,r on ! basis ( its frequ5cy4 ,let u n[ try ^! assumptions on ! fir/ two l9es ( ! message4 ,we h ,a ,a ,a ,r ,e ,n ,o ,r ,e ,e ,n ,t ,n ,t ,o ,n ,n ,i ,i ,i ,?is is cle>ly ! ^w ,,re9=cem5ts &1 us+ ! lett]s ?us f\nd1 ! re/ ( ! l9e becomes ,,ammunition&4 ,we h !n ! foll[+ lett]s det]m9$3 ,arbitr>y lett]s ,a ,b ,c ,d ,e ,f ,g ,h ,i ,j ,k ,l ,m ,pla9 ,text ,r ,e ,i ,n ,f ,o ,c ,m ,t ,s ,a ,u ,d ,if ^! be sub/itut$ we h = ! message3 ,,re9=cem5ts ,,ammunition ,,& ,,rations ,,mu/ ,,arri,e ,,e=e ,t,e ,,fifte5t ,,or ,e ,,_c ,o,d ,,out4 ,f ?is ! rema9d] ( ! lett]s are det]m9$3 ,arbitr>y lett]s ,n ,o ,p ,q ,r ,s ,pla9 text ,v ,b ,h ,w ,l ,x ,n[ let u sub/itute ! two-lett] gr\ps = ! arbitr>y lett]s3 ,arbitr>y lett]s ,k ,o ,g ,m ,b ,e ,p ,c ,r ,h ,d ,f ,a ,j ,i ,l ,n ,q ,s ,two-lett] gr\ps ,,gg ,,rg ,,ag ,,ng ,,tg ,,gr ,,ar ,,nr ,,ga ,,ra ,,aa ,,na ,,rn ,,an ,,nn ,,tn ,,gt ,,rt ,,at ,pla9 text ,a ,b ,c ,d ,e ,f ,h ,i ,l ,m ,n ,o ,r ,s ,t ,u ,v ,w ,x ,x is evid5t t ! ciph] 0 prep>$ ) ! lett]s ( ! ^w ,,grant *os5 by means ( a squ>e ( ?is k9d3 ,g ,r ,a ,n ,t ,g ,a ,b ,c ,d ,e ,r ,f ,g ,h ,i ,k ,a ,l ,m ,n ,o ,p ,n ,q ,r ,s ,t ,u ,t ,v ,w ,x ,y ,z ,?us ,,tg,e1 ,,an,s1 etc41 z we h already f\nd4 ,case #i-;b ,message #aiejdibieh #cabcbebhae #ddahdebhae #bjdhaaejda #bbebaaecde #ehdiacdabd #ejbheebebf #eiccaiebbb #ebdeaacbae #fbaeehdadc #bhfacfabfe #bideefejae #bcdbdeehej #fcdeedbjai #aeejahecaa #baaedaehbh #aabdagdeec #deedbjeiej #beebdedacb #aeccdibjdh #ejahaebcfd ,an exam9ation ( ! gr\ps ( two num]als ea* :i* make up ?is message1 %[s t we h #aa to #cf & #da to #fe ) elev5 gr\ps miss+4 ,n[ ! #aa to #cf comb9ation is a v famili> "o 9 num]al sub/itution ciph]s 7,see ,case #f-;c7 & x w be not$ t #da to #ff w\ld give u a simil> alphabet4 ,let u make a frequ5cy table 9 ?is =m3 ,gr\p ,frequ5cy ,gr\p ,frequ5cy #aa #aaaaa #da #aaaaa #ab #a #db #a #ac #a #dc #a #ad #dd #a #ae #aaaaaaaaa #de #aaaaaaaaa #af #df #ag #a #dg #ah #aaa #dh #aa #ai #aaa #di #aaa #bj #aaaa #ej #aaaaaaaa #ba #a #ea #bb #aa #eb #aaaa #bc #aaa #ec #aaa #bd #aa #ed #aa #be #aaa #ee #a #bf #a #ef #a #bg #eg #bh #aaaaa #eh #aaaaa #bi #aa #ei #aa #cj #fj #ca #a #fa #a #cb #aa #fb #a #cc #aa #fc #a #cd #fd #a #ce #fe #a #cf #a #ff ,ea* ( ^! tables looks l ! normal frequ5cy table except = ! position ( #bj & #ej :i* %\ld repres5t ,t1 by all our rules1 & %\ld be app>5tly #cj & #fj4 ,b suppose we put ! alphabet & correspond+ num]als 9 ?is =m3 #a #b #c #d #e #f #g #h #i #j #a or #d ,a ,b ,c ,d ,e ,f ,g ,h ,i ,j #b or #e ,k ,l ,m ,n ,o ,p ,q ,r ,s ,t #c or #f ,u ,v ,w ,x ,y ,z ,!n ,a#aa or #da1 ,j#aj or #dj & ,t#bj or #ej z we f\nd4 ,us+ ! above alphabet1 ! message may easily be read4 ,note t ?is ciph] is made up ( t5 *>act]s only1 ! ,arabic num]als4 ,case #i;c-- ,message #aaefbedfgf #bedbbiddcb #aidibidjae #adbcbagbaa #bigigjcaae #dibdbaceaa #gdbdadghge #gfdfbebddd #eadcbedhde #cagigdbecc #djeedfaeab #gegcbbgide #afbgdhaeaa #gjdbceaidd #acghbebadi #beadgfdeec #aedhcdbabf #gbaebedjge #afaabeghde #dfdbbagdae #diebaigibi #gjaebdbadc #bibedddicc #aigjahgeca #djgibedhbi #deeadiadaa #gcbaagaeed ,an exam9ation ( ?is message %[s x to consi/ ( =ty-f\r diff]5t two-figure gr\ps runn+ f #aa to #gi4 ,let u prep>e a frequ5cy table ( ^! gr\ps4 ,gr\p ,frequ5cy #aa #aaaaaa #ab #a #ac #a #ad #aaaa #ae #aaaaaaaaa #af #aa #ag #a #ah #a #ai #aaaa #bj #ba #aaaaaaa #bb #a #bc #a #bd #aaaa #be #aaaaaaaaaaa #bf #a #bg #a #bh #bi #aaaaaa #cj #ca #aaa #cb #a #cc #aa #cd #a #ce #aa #cf #cg #ch #ci #dj #aaaa #da #db #aaa #dc #aa #dd #aaaa #de #aaaaa #df #aaaa #dg #dh #aaaa #di #aaaaaa #ej #ea #aa #eb #a #ec #a #ed #a #ee #a #ef #a #eg #eh #ei #gj #aaaa #ga #gb #aa #gc #aa #gd #aaa #ge #aaaa #gf #aaa #gg #gh #aaa #gi #aaaaa ,we at once note ! resemblance betwe5 ! frequ5cy tables = ! gr\ps #aa to #ai & #ba to #bi2 = ! gr\ps #cj to #cf & #ej to #ef2 & = ! gr\ps #dj to #di & #gj to #gi4 ,also ! gr\ps #aa to #ai & #ba to #bi h a frequ5cy fitt+ well ) ! normal frequ5cy table ( ! lett]s ,a to ,i2 ! gr\ps #da to #di & #ga to #gi h a frequ5cy fitt+ well ) ! normal frequ5cy table ( ! lett]s ,k to ,s2 & ! gr\ps #ca to #cf & #ea to #ef h a frequ5cy fitt+ well ) ! normal frequ5cy table ( ! lett]s ,u to ,z4 ,we h ,j & ,t unacc\nt$ =1 b note :at occurr$ 9 ,case #i-;b & t #dj & #gj w\ld correspond well ) ,t if !y foll[$ respectively #di & #gi4 ,we may n[ make up a ciph] table z foll[s3 #a #b #c #d #e #f #g #h #i #j #a or #b ,a ,b ,c ,d ,e ,f ,g ,h ,i ,j #d or #g ,k ,l ,m ,n ,o ,p ,q ,r ,s ,t #c or #e ,u ,v ,w ,x ,y ,z & ?is table w solve ! ciph] message4 ,9 ciph]s com+ "u case #i-;b & #i-;c1 x is n uncommon to assign "s ( ! unus$ numb]s su* z #he1 #ic1 etc41 to :ole words 9 common use or to names ( p]sons or places4 ,9 case su* gr\ps are f\nd1 ! mean+ mu/ be guess$ at f ! context2 b if _m messages 9 ! same ciph] are available1 ! mean+ ( ^! gr\ps w soon be obta9$4 ,! appe>ance ( su* odd gr\ps ( figures 9 a message does n int]f]e mat]ially ) ! analysis1 & x w be app>5t at once on deciph]+ ! message t !y repres5t :ole words in/ead ( lett]s4 ,,*apt] ,,ix ,,o!r ,,sub/itution ,,me?ods ,! =ego+ cases by no means exhau/ ! possibilities ( ! sub/itution ciph] b !y cov] practically all me?ods :i* are satisfactory = milit>y purposes1 hav+ 9 m9d cons]vation ( "t1 ! m9imiz+ ( m5tal /ra91 & ! requirem5ts t complicat$ app>atus & rules be avoid$1 & t ! result+ ciph] %\ld be adapt$ to telegraphic correspond5ce4 ,a message may be re-enciph]$ two or m times us+ a diff]5t key ^w ea* "t or x may be enciph]$ by "o me?od & re-enciph]$ by ano!r me?od1 us+ ! same or a diff]5t key ^w4 ,complicat$ ciph] sy/ems requir+ ! memoriz+ (1 or ref]5ce to1 num]\s rules h be5 devis$ = special purposes4 ,su* sy/ems usually fail utt]ly if !re are any errors 9 transmission & x w be se5 lat] t su* errors are v common4 ,!re are sev]al +5i\s ciph] ma*9es by :i* complicat$ ciph]s c be =m$1 b if ! app>atus is available & fairly long messages are at h& = exam9ation1 x is usually possible to solve !m4 ,su* ma*9es are n1 z a rule1 simple & small en\gh = field use2 & x mu/ always be rememb]$ t a ma*9e ciph] op]ates on c]ta9 me*anical cycles1 :i* c be det]m9$ if ! ma*9e is available4 ,a book by ,comm&ant ,baz]ies1 entitl$ ,etude sur la ,cryptographie ,militaire1 & a s]ies ( articles by ,a4 ,collon1 entitl$ ,etude sur la ,cryptographie1 :i* appe>$ 9 ! ,revue de ,l',arme ,belge1 #ahii-aijb1 give illu/rations & details ( op]ation ( sev]al ( ^! ciph] ma*9es & ! latt] goes into ! me?ods ( deciph]+ messages enciph]$ ) !m4 ,^! me?ods ( analysis require long messages1 & z ea* "o is adapt$ only to ! product ( a c]ta9 ma*9e or app>atus1 x is n consid]$ advisable to include a discussion ( !m "h4 ,^? int]e/$ 9 su* advanc$ ciph] "w mu/ ref] to ^! & o!r ,european au?ors on ! subject4 ,! requirem5t t ciph] messages %\ld be adapt$ to telegraphic transmission1 practically excludes ciph]s 9 :i* ?ree or m lett]s or :ole words are sub/itut$ = ea* lett] ( ! pla9 text4 ,su* ciph]s might be us$ = ! transmission ( v %ort messages b 9 no o!r case4 ,! ciph] ( ,case #g1 ) a key ^w or phrase long] ?an "o-f\r? ( ! message1 ! ciph] aft] ! me?od ( ,case #g1 us+ a c]ta9 page ( a book z a key1 & ! ciph] ) a runn+ key1 :]e ea* lett] ( ! ciph] is ! key = enciph]+ ! next lett]1 all look safe & desirable1 !oretically1 b1 practically1 ! "w ( enciph]+ & deciph]+ is hopelessly sl[1 & errors 9 enciph]+ or transmission make deciph]+ v difficult4 ,incid5tally ! fir/ & second ( ^! ciph]s c be solv$ by ! special solution = ,case #g1 & ! ?ird c be solv$ by try+ ea* ( ! tw5ty-six lett]s ( ! alphabet z ! fir/ key lett]1 & !n cont9u+ ! "w = five or six lett]s ( ! ciph]4 ,:5 ! prop] prim>y key lett] is f\nd1 ! solution ( ! next five or six lett]s ( ! ciph] w make s5se1 & !reaft] ! ciph] (f]s no difficulty4 ,!re are num]\s o!r me?ods ( prep>+ :at is virtually a v long1 or ev5 an indef9itely long key f a %ort key ^w1 b all su* ciph] me?ods h ! same practical disadvantages ( sl[ness ( op]ation & difficulty 9 deciph]+1 if errors ( enciph]+ or transmission h be5 made4 ,! ciph]s ( ,napoleon 7 long s]ies ( numb]s repres5t+ lett]s1 syllables & words4 ,!y 7 really codes2 & a code bas$ on ^! pr9ciples1 b us+ lett]s in/ead ( num]als1 might be evolv$ v easily4 ,! ,w> ,dep>tm5t ,code1 ! ,we/]n ,union ,code1 &1 9 fact1 all codes are no?+ b specializ$ sub/itution ciph]s 9 :i* ea* code ^w repres5ts a lett]1 ^w or phrase ( ! pla9 text4 ,comb9$ ,transposition & ,sub/itution ,me?ods ,x is evid5t t a message c be enciph]$ by any transposition me?od1 & ! result enciph]$ aga9 by any sub/itution me?od1 or vice v]sa4 ,b ?is takes "t & leads to errors 9 ! "w1 s t1 if su* a process is employ$1 ! sub/itution & transposition ciph]s us$ are likely to be v simple ones :i* c be op]at$ ) fair rapidity4 ,on prelim9>y det]m9ation1 a ciph] prep>$ by su* a comb9ation ( me?ods w appe> to be a sub/itution ciph] to be solv$ z su*4 ,! frequ5cy table ( ! result w resemble ! normal frequ5cy table1 al?\gh ! message w /ill be un9telligible & we w "k at once t x is a transposition ciph] = fur!r solution4 ,! sub/itution me?ods usually f\nd 9 comb9ation ciph]s are ^? ( ,case #d1 #e & #f1 & ! transposition me?od is ne>ly always ,case #a1 & p>ticul>ly ! simple v>ieties ( ?is case l ! f5ce rail 7,case #a-;i71 rev]s$ writ+ or v]tical writ+4 ,a few examples w %[ "s ( ! possible comb9ations4 ,! fir/ l9e ( ! message ( ,case #d-;a is3 ,,obqfobpbrp ,we might write x ,,bfbbpoqopr 7,case #a-;i71 or ,,prbpb(qbo 7,case #a1 rev]s$ writ+71 or ,,(qboprbpb 7,case #a1 rev]s$ by gr\ps ( five74 ,! fir/ l9e ( ! message ( ,case #b-;b is3 ,,slc( ,,weetn ,,ebrdo ,,orvym ,,ff$i ,we might write x ,,tmdpg ,,xffuo ,,fcsep ,,pswzn ,,ggfej1 or ,,rkbne ,,vddsm ,,daqcn ,,nquxl ,,e$* 7,case #d-;a1 go+ =w>d "o lett] or back "o lett]74 ,^! examples give an idea ( ! use ( comb9ation me?ods4 ,x is v r>e to f9d bo? complicat$ transposition & sub/itution me?ods us$ 9 comb9ation4 ,if "o is complicat$1 ! o!r w usually be v simple2 & ord9>ily bo? are simple1 ! s5d] dep5d+ on ! comb9ation ( ! two to atta9 indeciph]ability4 ,x is evid5t h[ futile ?is idea is4 ,me?ods ( ,enciph]+ ,num]als ,x is frequ5tly desirable to s5d num]als 9 ! body ( a ciph] message4 ,sev]al ciph] sy/ems prescribe t all num]als 9 ! body ( a message mu/ be spell$ out2 &1 :ile !re is no d\bt b t ?is insures great] accuracy1 x also greatly increases ! l5g? ( su* messages4 ,9 mo/ sy/ems 9 :i* x is p]missible to s5d num]als1 ! foll[+ sy/em is us$4 ,an indicator1 "o ( ! little us$ lett]s & especially ,x1 is int]polat$ be=e & aft] ! num]al or num]als to be enciph]$1 & !n1 = ea* num]al1 a lett] is sub/itut$ us+ ?is or a simil> table3 #a #b #c #d #e #f #g #h #i #j ,a ,b ,c ,d ,e ,f ,g ,h ,i ,j ,! enciph]+ ( ! message !n proce$s1 deal+ ) ! indicator & sub/itut$ lett]s z if !y 7 ! lett]s ( a ^w4 ,! deciph]] arriv+ at an ,x1 a s]ies ( ! lett]s ( ! above table & ano!r ,x1 ca/s out ! ,x's & sub/itutes numb]s = ! lett]s4 ,sometimes no indicator is us$1 b ! sy/em ( sub/itution ( a c]ta9 lett] = ea* num]al is foll[$4 ,aga91 ! indicator ,,nr may be us$ in/ead ( a s+le lett]4 ,conv5tional lett]s may also be sub/itut$ = special *>act]s l 81 1 1 -1 & p]iods & commas1 b ?is is r>ely done except = ! p]iod & "q m>k4 ,! context w usually det]m9e ! mean+ ( su* lett]s :5 f\nd4 ,9 ?is connection1 ! use ( ,x to repres5t end ( a s5t5ce & ,q to repres5t a "q m>k is q common4 ,,*apt] ,x ,,errors ,,9 ,,enciph]+ ,,& ,,transmission ,"o ( ! mo/ difficult tasks be=e ! ciph] exp]t1 is ! correction ( errors :i* creep into ciph] texts 9 ! process ( enciph]+ & transmission by telegraph or radio4 ,9 "s ciph] me?ods a mi/ake 9 enciph]+ "o lett]1 or ! omission ( "o lett]1 w s mix up ! deciph]+ process t only "o famili> ) su* errors c apply ! necess>y corrections4 ,! transmission ( ciph] text ov] ! telegraph or by radio is a sl[ process1 & _m fairly good op]ators _c receive su* matt] satisfactorily1 because !y li/5 = words & guess at lett]s at times4 ,! spac$ lett]s 9 ,am]ican ,morse are ! cause ( s _m errors 9 code transmission t ! ,w> ,dep>tm5t ,code does n employ any gr\ps us+ !m4 ,9 fact1 ?is code is limit$ to ! lett]s ,a ,b ,d ,e ,f ,g ,i ,k ,m ,n ,s ,t ,u ,x s t !re may be a m9imum ( su* confusion4 ,9 ciph] "w x is necess>y1 "u ord9>y circum/ances1 to use any or all ( ! lett]s ( ! alphabet4 ,to assi/ op]ators 9 keep+ ! text /raight1 x is cu/om>y to divide ciph] text into gr\ps ( f\r1 five1 six or t5 lett]s1 & usually gr\ps ( five lett]s are us$4 ,! receiv+ op]ator may !n expect five lett]s p] gr\p1 & if he receives m or less he is sure t ei!r he or ! s5d+ op]ator has made an error4 ,?is division into gr\ps ( a con/ant numb] ( lett]s elim9ates ^w =ms &1 9 ! m9d ( ! non-exp]t1 increases ! difficulty ( solv+ ! ciph]4 ,b ! increase 9 difficulty is m app>5t ?an real2 p>ticul>ly1 z a ciph] exam9] habitually f9ds himself deal+ ) ciph]s )\t ^w =ms1 & ! occurr5ce ( a ciph] ) ^w =ms usually means t he has an easy "o to h&le4 ,messages are occasionally enc\nt]$ :i* consi/ p>tly ( pla9 text & p>tly ( ciph]4 ,! ciph] "p may or may n reta9 its ^w =ms1 b1 :5 ?is me?od is us$1 x is cle>ly impossible to h a fix$ numb] ( lett]s 9 ea* ciph] gr\p if ! ^w =ms are n us$4 ,x is almo/ impossible to prev5t errors ( transmission 9 su* messages1 & x (t5 requires consid]able skill & labor to correct !m4 ,= ^? unfamili> ) ! telegraph alphabets1 !y are giv5 bel[4 ,messages s5t by comm]cial or milit>y telegraphs or buzz] l9es w be transmitt$ ) ! ,am]ican ,morse alphabet4 ,^? s5t by radio1 visual signall+ or subm>9e cable w be transmitt$ by ,cont95tal ,morse1 kn[n also z ! ,int]national ,code4 ,messages may be transmitt$ by bo? alphabets 9 c\rse ( transmission4 ,= example1 a cablegram f ! ,philipp9es to ,nome1 ,alaska1 w be transmitt$ by ,cont95tal ,morse 7comm]cial cable7 f ,manila to ,san ,francisco1 by ,am]ican ,morse 7comm]cial l& l9e7 f ,san ,francisco to ,seattle1 by ,cont95tal ,morse 7milit>y cable7 f ,seattle to ,valdez1 by ,am]ican ,morse 7milit>y l& l9e7 f ,valdez to ,nulato & by ,cont95tal ,morse 7milit>y radio7 f ,nulato to ,nome4 ,prior to ,febru>y1 #aiad1 ! ,mexican gov]nm5t telegraph l9es us$ an alphabet diff]+ slightly f ! ,am]ican & ,cont95tal ,morse4 ,h[ev]1 at t "t1 ! ,cont95tal ,morse alphabet 0 prescrib$ = use on ^! l9es & x is believ$ t ! use ( ! old alphabet has entirely ceas$ on ,mexican l9es4 ,h[ev]1 skill$ ,am]ican op]ators w\ld h no difficulty 9 pick+ up ?is alphabet if x 7 f\nd to be 9 use4 ,radio communication is1 by ,int]national ,conv5tion1 inv>iably 9 ,cont95tal ,morse4 ,telegraph ,alphabets ,"* ,am]ican ,morse ,cont95tal ,morse or ,int]national ,code ,a 4 - 4 - ,b - 4 4 4 - 4 4 4 ,c 4 4 4 - 4 - 4 ,d - 4 4 - 4 4 ,e 4 4 ,f 4 - 4 4 4 - 4 ,g - - 4 - - 4 ,h 4 4 4 4 4 4 4 4 ,i 4 4 4 4 ,j - 4 - 4 4 - - - ,k - 4 - - 4 - ,l -- 4 - 4 4 ,m - - - - ,n - 4 - 4 ,o 4 4 - - - ,p 4 4 4 4 4 4 - - 4 ,q 4 4 - 4 - - 4 - ,r 4 4 4 4 - 4 ,s 4 4 4 4 4 4 ,t - - ,u 4 4 - 4 4 - ,v 4 4 4 - 4 4 4 - ,w 4 - - 4 - - ,x 4 - 4 4 - 4 4 - ,y 4 4 4 4 - 4 - - ,z 4 4 4 4 - - 4 4 #a 4 - - 4 4 - - - - #b 4 4 - 4 4 4 4 - - - #c 4 4 4 - 4 4 4 4 - - #d 4 4 4 4 - 4 4 4 4 - #e - - - 4 4 4 4 4 #f 4 4 4 4 4 4 - 4 4 4 4 #g - - 4 4 - - 4 4 4 #h - 4 4 4 4 - - - 4 4 #i - 4 4 - - - - - 4 #j ---- - - - - - ,p]iod 4 4 - - 4 4 4 - 4 - 4 - ,"q ,m>k - 4 4 - 4 4 4 - - 4 4 ,comma 4 - 4 - - - 4 4 - - ,! foll[+ example w %[ "s ( ! errors t creep into messages prep>$ ) ! ciph] disk & transmitt$ by radio3 ,message ,radio ,d\glas de ,el ,paso1 #b ,h #ga1 tw5ty-fif?1 #i3jj a4m41 ,govt4 ,to ,c4,o41 ,six? ,brigade1 ,d\glas1 ,arizona3 ,,jprzi ,,rdjsg ,,xtrmj ,,usfpc ,,recla ,,bcpcb ,,oaxpk ,,qeqkf ,,ppzae ,,bkutt ,,jhweu ,,ahpze ,,ezolt ,,hkxph ,,kihav ,,drodn ,,iapzc ,,lvump ,,kfubv ,,vtvnv ,,efvzv ,,tlvqs ,,bkahq ,,nvkvf ,,mgj? ,,owbgn ,,wwepo ,,ljkfp ,,hexkw ,,cpdlz ,,jwsqc ,,jvkig ,,htjht ,,egaha ,,gdxxk ,,bsppk ,,diavz ,,vqonc ,,hovda ,,vzqkw ,,fnvon ,,rpvgh ,,cufpv ,,sfpie ,,tozod ,,wgyfe ,,awnjy ,,ko$w ,,umeld ,,nobuh ,,mupql ,,gyopp ,,odbab ,,ufuuc ,,aeojw ,,rdipk ,,wmokv ,,omicw ,,ckpih ,,lumsy ,,yosbg ,,wophv ,,pkomo ,,phg] ,smi?4 ,! key ^w is ,,at*ison1 ! ciph] disk be+ us$ & ! sett+ *ang$ = e lett] ( ! message4 ,! lett] ,x indicates a p]iod :]e x is evid5tly n a lett] ( a ^w4 ,deciph]+ ! message ) ?is key & me?od we h3 ,,relia ,,ble9 ,,=gf ,,tionf ,,romca ,,sasgr ,,&es ,,recei ,,l$he ,,re?a ,,tam\ ,,nt$d ,,eta* ,,msktl ,,eft? ,,erela ,,/nig ,,httoe ,,scort ,,%ymp ,,ent( ,,armsa ,,ndamm ,,uniti ,,ontob ,,esmug ,,gl$a ,,crjxs ,,borde ,,rnext ,,frida ,,ynigh ,,tatap ,,o9tt ,,welve ,,mi5x ,,fkosb ,beyond ?is po9t ! message1 if we cont9ue ! deciph]+ process1 is un9telligible4 ,! s5se fails at ! fir/ ,p ( ! ciph] gr\p ,,bsppk4 ,we h translat$ ,b z ,m ) disk ,a to ,n & ,s z ,i ) disk ,a to ,a4 ,! la/ words t make s5se are ,a ,,po9t ,,twelve ,,mi2 cle>ly ! re/ ( ! la/ ^w is ,,les & ?is is repres5t$ by ,,ppk4 ,putt+ ,p,l !n ,a,a & putt+ ,p,e !n ,a,t4 ,9 o!r words1 ! enciph]] =got to *ange 8 disk sett+1 ,a to ,a1 aft] enciph]+ ,i into ,s & enciph]$ ,l into ,p ) ! same sett+1 ,a to ,a4 ,cont9u+ ! deciph]+ on ?is basis1 we h3 ,,les ,,ea/o ,,fd\g ,,las4,t ,,hisis ,,iny\ ,,rdi/ ,,rict4 ,,willy ,,outak ,,enece ,,ss>v ,,/eps ,,topre ,,v5tt ,,his% ,,ipm5 ,,tfrom ,,go+ ,,skzrx ,,leade ,,r(sm ,,uggle ,,rssal ,,dtobe ,,juanh ,,ernan ,,dez( ,,naco4 ,! m9or errors und]l9$ above are n difficult to correct except ! six? ^w 9 ! eigh? l9e4 ,!y w be tak5 up h[ev] = analysis ( cause ( error4 ,l9e #a1 ,,gf %\ld be ,,ma4 ,putt+ ! latt] into ciph] we f9d ! lett]s ( ! ciph] %\ld h be5 ,,g in/ead ( ,,mj4 ,?is is cle>ly a telegraph]'s error1 --4 --- becom+ -- 4--- ,l9e #b1 ,l %\ld be ,v4 ,! correspond+ ciph] lett] %\ld be ,f in/ead ( ,p4 ,?is is an error ( ! enciph]] 9 copy+4 ,l9e #b1 ,,sk %\ld be ,,en4 ,! correspond+ ciph] lett]s %\ld be ,,yu in/ead ( ,,kx4 ,ano!r telegraph]'s error1 -4-- 44- becom+ -4- -44- ,l9e #c1 ,y %\ld be ,i4 ,! correspond+ ciph] lett] %\ld be ,l in/ead ( ,v4 ,ano!r error 9 copy+ by ! enciph]]4 ,l9e #d1 ,,jx %\ld be ,,os4 ,! correspond+ ciph] lett]s %\ld be ,,fk in/ead ( ,,kf2 an error on ! "p ( ! enciph]] 9 copy+4 ,l9e #g1 ,v %\ld be ,y4 ,a mi/ake 9 copy+4 ,l9e #h1 ,,skzrx4 ,if we take ,x z a p]iod1 !n ?is l9e might be ,,ov]1 ! ,r be+ correct & ,,skz be+ 9 "q4 ,! correspond+ ciph] lett]s are ,,aeo & if we enciph] ,,ove we get ,,etj4 ,"h aga9 we h a telegraph]'s error1 4 - 4--- becom+ 4- 4 --- ,l9e #i1 ,l %\ld be ,i4 ,! correspond+ ciph] lett] %\ld be ,k in/ead ( ,h2 an error 9 copy+ by ! enciph]]4 ,! errors by ! enciph]] above not$ are fairly common ones4 ,^! & simil> errors are usually f\nd :5 a ciph] message1 prep>$ z a r\gh draft by ! enciph]]1 is copi$ by a cl]k & a c>eful *eck ( ! copy is n made4 ,! lett]s mi/ak5 dep5d1 ( c\rse1 on ! enciph]]'s h& writ+ or pr9t+4 ,o!r errors1 besides ^? not$1 are ! confusion ( ,c1 ,g1 & ,q2 ,i1 & ,j2 ,b & ,r1 etc4 ,! error by ! enciph]]1 9 n *ang+ 8 disk sett+ = "o lett] & ?us ?r[+ out ! :ole process ( deciph]+1 w\ld n h occurr$ _h he put ! message into eight columns or a multiple !re( & enciph]$ ea* column ) "o disk sett+4 ,?is latt] me?od is also v mu* fa/]4 ,telegraph]s' errors 9 ciph] transmission are common & (t5 v confus+4 ,note %\ld be tak5 z to :e!r ,cont95tal or ,am]ican ,morse 0 us$ = transmission4 ,an analysis along ! l9es indicat$ w usually develop ! error & correction4 ,if n1 a repetition %\ld be dem&$1 call+ att5tion1 if possible1 to ! p>ticul> gr\ps t are n cle>4 ,! deciph]$ & correct$ message is3 ,reliable in=mation f ,casas ,gr&es receiv$ "h t a m\nt$ deta*m5t left !re la/ night to escort %ipm5t ( arms & ammunition to be smuggl$ across bord] next ,friday night1 at a po9t twelve miles ea/ ( ,d\glas4 ,?is is 9 y\r di/rict4 ,w y take necess>y /eps to prev5t ?is %ipm5t go+ ov]8 ,lead] ( smuggl]s said to be ,juan ,h]n&ez ( ,naco4 ,ano!r rem>kable example ( errors 9 transmission by ,am]ican ,morse is ! foll[+3 ,a message1 p>tly 9 ciph] & p>tly 9 pla9 text1 conta9$ ! ciph] words ,,ga ,,gtxieit ,,eidisxq ,?is1 deciph]$ z f> z possible by ! alphabet det]m9$ by analysis ( ! re/ ( ! ciph]1 read ,,su ,,sme,y,m ,y,o,,ges ,x 0 f9ally decid$ t ! context requir$ a s+le ^w l ,,susp5dio or ,,susp5dioles = ?is ciph] gr\p4 ,an exam9ation along ?is l9e %[$ t ! ciph] words %\ld h be5 receiv$ ,g ,a ,g ,l ,x ,c ,u ,r ,d ,p ,x ,g & 7 receiv$ ,g ,a ,g ,t ,x ,,ie ,,x ,,ei ,d ,,is ,x ,q & t !re 7 five errors 9 transmission 9 ^! ?ree ciph] gr\ps alone4 ,,notes #a ,occurr5ce r>e1 usually 9 prop] names4 #b ,! me?od us$ is n ! mo/ satisfactory "o = sev]al reasons & a bett] me?od is t ( writ+ ! message 9 multiples ( ! key & enciph]+ ! columns z already describ$4