![[JoGu]](../../JGU.gif) |
CyptologyCiphertext-Only Attack: Example |
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CyptologyCiphertext-Only Attack: Example |
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We take the complete ciphertext:
NHAHREDBVYTUFKRVWMCOYKFELQFCYNRSOIXVEVCXUCGZCYXVGYHFWPIQVWKMHIGQPGPAOKTBOAEBEXFUSAAJALOCWNJVFVVVVWGand decrypt it with each rotor in each position to an intermediate text as for attack 1. Instead of looking for the numerical pattern we calculate the coincidence index of the intermediate text and look if it seems to be random (0.0385) or monoalphabetic (0.0661 for English).
We can't expect a clear-cut result because we don't have a homogeneous monoalphabetic text but rather a join of 4 or 5 distinct monoalphabetic chunks of lengths ≤ 26.
For rotor A the results are:
VFNGZRQPDDJKEXQTUIYKXPVXTGWRLJZALXCYSRFTSKJWYPWICNXDJZGYLMJDUVTHOFEDBJIYCRBACKWTVNNIOKMBZMWSVTMUUVJ 0.033 QYNGURQAYIQRKXQMNASCXUCCOTEPUDUVHVHYDLHNLFLSSXWIWLEWSXZTYZJLUVCPOLCWBPGUNZXAVKEZXNWIZKFHZCWOIMUUUVJ 0.037 QGNGURZGYGMNVGGUVLZNXSYVOVEPMKUVMVFRJSMUTFQXZXMIDLAEKSHTABJLUVUPEWCQBAGZTZCADKEKCWOIFKNSSAFTKUUUKLC 0.039 JGWWNRRRRBRSIYEUVRVTNNDDHAEPXGNOFVALUOKQTYOQVXKIZLFEVSHMFGZLUVFPCJCXKNGSEZVQDTEXAOZYQANFMAXMPUUKIJW 0.033 DGOUHACELBKLKJEUVCAELNWDBYUPDLHINVASHTFVTSJYANKIELYEBLHGDEXBDELFCLCTCPGARPDODLUZVZFWDYNHTAIUNUKIIJD 0.041 <=== KWZUOSIGSUSTPPEKLPTRLGEDITSPOEOPNVTOJMFOJZJYTLKRXLGUMFXNYZXZVWWDCQCYNUGATNDOTWSEVFQWFYDMPAOUIKIIIJZ 0.036 GUFUKDTLOOSTNAEIJRBTLAETETSYBMKLNENTOUYWHVCYBLKJFUGSZMVJYZXZGHJDCOLRTSPAYNDORCSCOQDWKYBKUAZUIIIIIJE 0.036 LUQUPJGJTVSTINEIJWBYLHERJMSQDMPQDWUMMUSWHAWOBLKUFMGSBIVORSXZMNLDCJDZENHQWNTORNSXIDFWIYBFNJMKBIIIIJX 0.039 EUDUIUIEMRIJIPNIJUBWLDURCGSBIMIJBHQUHUZWHTDMBLTAFXWSGNVHLMXZXYQDLJOZRNSORNRORASXPFKWDYBFVBOIVIIIRSF 0.041 <=== MUFDQHNEUWGHBUFIJPRRUISRKNSHGCQRBNVUHKVMHBZMRLLLVDUSEGVPSTGZKLODDCUZTGYORNRXRCSQLKIFDHBYVMTICIIRJKF 0.039 MUKVQJLXUPGHVSQIJPPRMBSRKJBSBAQRBYOUAIAKHBEMPUWYTOUSZOVPOPYIMNJMOWFPYAJOKWRPRHBKQIDXWZBSVSRIYIRJUVF 0.042 <=== MDIGQOGRUXGHCNWRSIPKXJSRKOTFBAQRBLWKUITKQBXMPMCATBUBZOEPTUJARSJEUDSNWHWOEORAAFTRJDDIQKKZLDMIDRJUABV 0.038 CVDMGMGYKXGHYNHJKCPEDJSAAHEHUAGHBNWIBIBKIRFMPXNFTDUTSOWFMNPLPQCPFZUNRDYOLZRGSAENRDWOXQCVJQMIWJUALMT 0.031 AGDXEHZUIXGHDGUUVJPLOJSSYPKMOAEFKSWIXIBKTPFVPDADTIUEMEHDUVARKLWVSEZNRIDXHFARDAKSRWQZTBNAJSFREUALYZT 0.036 AMWKEHTZINPQWAWABFPHBZBDYPVKVAEFCQMICIBKZPFNPOCYTGDKTCNDUVNCKLDGUXXNKBBPMQSEJTVLRQXMYOTTJXZJEALYABT 0.035 AXQMEAASILHIEHBLMKYMDXTJYPIFRJEFNLKIVRRTKPVYYBHYCBVVPCYDUVPPDEZTZFSNEJWAFDDGUNITHXTORQEBJVGUELYAFGT 0.035 AKXREUWAILSTEDZYZDQFIXEUYFKFWBEFTLKIDJPLXPTEQDFRUBGIUCLDKLURXYEVXFSWLJWGNFJLHUKTFTYTZVRBJQCAUYAFDET 0.042 <=== AMTPEBBAILYZEIUABLBNGXKHYDPYPMEFEEKRDUPWZPTPBIALFUMKNCNDIJSWEFXASFLOHJPRNKUJJQPTFYRRZTTBSQHLSAFDYZC 0.036 JRYKNXUARLJKUBUFGLHNBXVJHDNSXSNORYKJDAPCEYTCHGASLOXPVCSMIJNUABFYSVFZMZJENIHEOVNJFRZMZOYRKJAYSFDYYZU 0.038 BPRKFCCQJLWXSJNDELSNBXIOZDIZXDFGTFKUTLPNCQTESBTOWVKNVLQEIJNPFGFTLTMFFXQGDDJEMOIHFZZMPOWPVDIASDYYRSF 0.037 MKZDQVCOUUYZSJHYZBFDUGKMKDIVXQQRYBTARYPAXBTJFBNTJRMIVDLPIJGPYZFTFTIQNXMLBDOXHWIHFZZFNHRPBKIFSYYRLML 0.037 SKZXWDCOAMDESJOYZZHBOYPHQDBANSWXWGLLRAYCXHCHHUUMLWRILOLVIJAIGHVMMTNDNXRJBWMRHWBHOZPZNBRPMGIDSYRLSTW 0.038 DDZEHDSOLXBCSZKRSZMBVJNHBMVTLXHIRZWYRFQHQSUCMOQUQPPBJUEGRSHCGHTGITGFNXKEBQHYAWVHGPNGNIKPZLYYBRLSOPJ 0.034 QXPAUDQOYDWXSXPLMZKBRPIAOECBLVUVRHCARDBFKFFCKVVUOXKVJFYTJKDJGHTNNTOKDXSEBXHUUMCHRNNCNEEPBEWYTLSOTUL 0.035 SENFWTQOAOWXBXISTZFBWAIUQPYBLQWXKHNFRYHARHLVFROUJXKCJSFVUVIFWXTJGCOIBGSXBTAZBKYQXNNHNJLYGMWRESOTMNQ 0.035 XANYBRQXFBPQTXQOPZFBPNBBVVDBLQBCEHADAYSANMWPFWWKJXDYJUBAABBKUVTOOUODBYSRKYUSXKDIINNAWCHQEMWLKOTMUVO 0.041 <===
And for rotor B:
RPAQVEDQZKPQGKADEMHOHWBDPSCMYSVWJSJTTAECCGIUHVGVLIDNWFQUXYTJHIGNYHZFOLDWDXZKMXCVUAASPUWDUSJQHDSEEFE 0.036 LEAQPEDCTOOPVKWSTBYDHAAMJSOCYJPQNINAFROTRASYYHCVCYCCWTFOXYTVHIGZUWPFOATAPJDKBXOKEAASBULSBXJUHSEEABL 0.040 SQAMWEDRACSTHKBEFNXPDOEBQCOCNIWXWIBAUQSSDHWHXHHVBYGOLNRVHIPVHIVZZIPWOMTJEJMGNXOWIAPOQQXEBNJDREEAFGL 0.036 SQARWESDAWBCHZREFCBEIINNQGKCZMWXLIVRGUGWDHKWBDXVFYPOXURVLMURHIHVPIPVOMTYQFBLNXKWWPBTCVXESNYSVEAFVWC 0.036 JMPHNEEDRDQRRLRABOKQYPCNHUPCOVNOXICQGDAFZYEIKIXVOYEKMUNMZAKWHIWAPSPZDWTKQKNBJMPGQBQJCLTORNKEJAFVVWB 0.034 IRBHMTTNQDCDVARFGOZQYPOJGOFCAKMNXICUQSHUEXLIZYXVDYQPYLSLTUKMWXIQPWPIPATKAANBOYFKXQCJMLYSVNZEDFVVVWF 0.032 MHQHQFFRUUCDJMRVWYLAYGOOKVFCAWQRTITDUEHGUBLELYXKPYQFYKIPABKMIJIQPKPXEOTGEAJBENFYXCCJQLOGENLAKVVVVWO 0.035 VHCHZUFFDTYZDMRVWCLEYFKETVFRKWZAYXSSIEYGUKCJLYXWPNMFIOIYABKMXYSQPEEJQIILSAOBEZFSOCMJELOATNLFKVVVVWD 0.036 KHCHOGPZSXDEKWRVWQHSYJPEIMFDOSOPOJWECAXCUZBZHYXLLZRFMXINRSKMJKWQPLQJQPUBMAEBEZFZNMQJYLOHFCVVBVVVVWP 0.035 WHMHAGTGEGTUKAGVWKMMYSFEULFSCXABOYFEJFBHULFZMYMXQOHFAMIZQRKMJKKQELFFAPJBTAEBEJFZRQEJFLOHFOZVAVVVKLP 0.045 <=== ! WHQWAQHGEVTUBOSVWRCTNHFEUPFEWNABOKUAJVKXULOZCYYXGAHFUYIZUVZMTUEQQCRKEGVBTAEQENFQAEYYFAOYBDNVEVVKWXL 0.042 <=== SHEIWUBXAHTUAIHVWRCTZTFEQYUEDNWXOKGFAVZXUHDZCNNHGAHFBYIVDELBXYLFFBRASFVBKPECEBUPPYFKWMOXGPHVNVKWLMQ 0.036 XWYXBIIWFHTUEPTKLICKOTFEVNGODNBCOUGVZVLXJMPZCZZLGKHUBUXASTANLMLRRFBAMJFBJBERTVGTBFFZVBDBWPOVCKWLXYG 0.037 NIFJRCIAVDTUNPTWXHCJAPFTLZVSUNRSOYCVDVLXVCPZCOZZGOHGSZJQEFMCFGCGROFATSJBNQEDFCVCBFWLZNPKWZOVOWLXXYG 0.039 NXFJRJZJVITUCGDLMLCNAUFFLZHGTNRSDMHVMVHXKCLOCAJTGCHVRPYQEFMOMNBSBDTATHXQWCTDUCHRXWVLINEZWDFKOLXXHIG 0.036 NJWTRJYYVYIJOFHXYUCWKKUULVHAXNRSPGXVBVMXWCQACANAGWWHVPKQABWOMNFSFPNAKTRCLCFNGTHDCVZVXXQLWREWKXXHLMG 0.039 NJVXRACKVYUVOJVXYJRLOKGGLARHGCRSENXVNKCMWCGPRKBAVDIHEPKQFGAYDEOCTPUAJTYRXMURGSRDSZIZJBQLWLILPXHLZAG 0.036 NTZLRZLKVYJKKSPHIVDXCKVGLQVHVORSQNXVNWCYGCGBDOVRHDXRTPUQVWOCCDDGNLUPNPYDXQGFQWVZSIXNJPAHWSRXFHLZTUG 0.039 NXIFRDAGVYVWPHWLMVSXWKHQLQJYHDRSQEXKJLCNKCGBSCCQWUJVFPYQVWIQGHPUUQLBWUPDTEGZUFJESXJHFJEMLSGXFLZTABV 0.036 CLXMGMMLKYVWFTWZARETDKHUAQDXHPGHADXWOXCZYRGLEWCUITJJFPMFVWPKPQPOUGKQLKONYYQGIUDUSJJOKQSCXJSHFZTAABH 0.033 OFJMSBMBWYFGFTNTUWEYDKRIMQKBDPSTEHXLEXCZSDGPEDTDIXTDBEGRVWPREFLVLGOCXKSROFUGCGKUSJFOAQMCMISLFTAARSW 0.036 DMJDHNIBLNJKFPMABMOOUZVCBQKKIZHISQMXEHCJZSGDODSSSGXKGQNGVWGRQRQVKGXCXKBFOFIXJGKUSFKFAHTCYMOZFAARQRI 0.038 PMFCTNNBXZXYFUQABMSOTLJJNQBZYDTUMFYXELRNZEVXSUWEWVLKWFNSVWFIQRGMOGMMTKQZOWCWJCBUHKAEAGTCYVTTFARQUVI 0.035 PDKGTJDBXORSFKZRSMGOXADJNFALYRTUTRNHEZDBQEHEGTFEKHFBWRESKLJHMNGLXGYQYKCGOVJAAHAUTAAIAKKCIKJAURQUDES 0.040 ZCAPDODBHAYZFKOQRMAOGMKAXRELYLDETRZLETSVPOWEAXUAEHMAWRDCWXSLRSGPMGYEOKCGOZJJZXEUIAARATJCMWJAGQUDSTW 0.042 <=== DGAEHEDBLAYZUKAUVMHOVMKZBGNHYSHIKNZZEAECTSIVHGGFLDMEWBHGLMHUHIGYYVUYOZYXOIAYDXNJUAAGAINRAWJRVUDSEFK 0.043 <===
The highest value, though not by much, is for rotor B in initial position 09 (0.045). Let's try this one first.
We take the intermediate text and decrypt it with rotor A in each position. This procedure should give several meaningful plaintext fragments.
Pos 00: JEUEPZHZVZHQNPZIJNUULRDVQODRBKPATLDVFDAEQODMULUKGTEDPUYMGWNUFNNGVODDPSFAHPVAVFDMWGVFDOTEDTMIPIIINOS
Pos 01: JAPANESEDESIGNERJGPPLXWDIOWXBKNQYLWDZWQAIOWMPLPKTYAWNPFMTHGPZGGTDOWWNUZQSNDQDZWMHTDZWOYAWYMRNRRRGOU
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That's it! Rotor order is A B, start positions 01|09. And we have the first 16 characters of plaintext.
If this is correct, monoalphabetically decrypting the intermediate text with rotor A in the next few positions should give the next 26 plaintext letters:
Pos 02: SFPFNXYXDXYTANXJSAPPLIEDTHEIRKNOWLEDGEOFTHEMPLPKVWFENPBMVUAPGAAVDHEENZGOYNDODGEMUVDGEHWFEWMJNJJJAHZ
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Pos 03: KYIYNFJFDFJZHNFUKHIILVEDZBEVPTNORLEDCEOYZBEMILITARYENIGMAWHICHHADBEENXCOJNDODCEMWADCEBRYERMUNUUUHBX
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Pos 04: VGCGNFWFTFWKDNFAVDCCUXETKIEXPLNORUETHEOGKIEMCUCLYRGENCZMYBDCHDDYTIEENSHOWNTOTHEMBYTHEIRGERMANAAADIS
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Pos 05: BGJGNFYFRFYXINFLBIJJMCURXEUCPWNOKMURAUOGXEUVJMJWTKGUNJHVTZIJAIITREUUNSAOYNRORAUVZTRAUEKGUKVLNLLLIES
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