Outpost Universe Forums

Off Topic => General Interest => Topic started by: Hooman on May 24, 2005, 11:53:38 PM

Title: Crypto Challenge #2
Post by: Hooman on May 24, 2005, 11:53:38 PM

Here you go, a formal cipher to solve.  B)

All punctuation and spacing were removed. The resulting text was encrypted using the same scheme as the first challenge. (Mono Alphabetic Single Substitution Cipher). The outpust was grouped into blocks of 5, and the last block was padded out to 5 characters if it was short.

Don't worry, I don't want to make these too hard too fast, so I made sure this one was somewhat easily solvable first. If this one is too difficult, I can post another one that is a little less "formal".

Code: [Select]

GERBL VZLYW ITPKT RKWMK KALJE BKWTT SLBEJ BKRNE OTVGS LOLEO LUTVB LIVJL IRKWT KAJGL RKWYW ITDEU TTKBK OOKDT SVITS KWPSV JITVA AAVCL TKCUK DDSRR KWDEU TTKBK OOKDT SLFEO PKVUT SLTOE VALOD EIEBE TTALJ EGEPL JARUX VTITW OOLTJ LITOK RLJJW OVUPT SLAEI TICVO GVISD VTSNA RGKWT STSLO LITKM TSLFS EIIVI BEJAR JEGEP LJVTS EJBLL UBKWU JMKOG LTEAO LFRFA VUPDS LUBOK KCSEJ VUTLO FLNTL JVTEB KWTTS LKUAR NKIIV BALWI LSLFK WAJTS VUCKM MKOVT DEIEI BEAAE ITLFS KISKK CSLOS LEJVG UKTOL EJRTK TOWIT RKWDV TSEAA KWOIL FOLTI RLTRK WCLLN NOKZV JVUPT SVUPI DLULL JEUJD LAATE ACEBK WTVTB WTUKT TKJER YWITT OWITG LKUTS VIKUL EUJVA ABLGW FSGKO LVUFA VULJT KTOWI TRKWV UTSLM WTWOL ISLIS KKCSL OSLEJ BEFCT KDEOJ TSLNK DLONA EUTKW TTSLO LIEIF KKTLO BEFCV UTSLO LFLII RKWFE UWILT KPLTB EFCTK TSLFK AKURO LAWFT EUTAR SLFAV GBLJK WTEII SLIAV JNEIT EUJVU TKTSL ILETS LOSEU JIOEU KZLOT SLFKU TOKAI DVTSE MEGVA VEOVT RSLJU LZLOM LATDS LUJOV ZVUPD SLOLS EJISL PKTTL UTSLF SEUFL TKNOE FTVFL TSETA KKCIP KKJVG KWTKM SLOLS LCLNT SVINL OFSKU TSLIT LNIDE VTDSL UDVAA RKWBL BEFCI SLFKU IVJLO LJSVI QWLIT VKUMK OEGKG LUTBL MKOLE UIDLO VUPEB KWTTD LUTRS KWOIM KOGRB WIVUL IINAW ITOEZ LATVG LFEAA VTTSV OTRMV ZLSKW OIMKO TRTKN IRKWI EVJUK BKJRD VAAUK TVFLT SLTOW FCVIG VIIVU PKNLO ETVKU ITSVU CIVTI VUTSL PEOEP LTSLP EOEPL TSVUC IVTIN EOTKM TSLIT EOISV NIEAZ EPLFK UZKRT SLTOW FCTSE TIEFT WEAAR VUTSL FKUZK RDEIO KTETL JKWTK MKOLS EWAVU PEUJD SLURK WBOVU PTSVI TOWFC BEFCV TDVAA OLNAE FLVTE IAKUP EIRKW BLETT SLFKU ZKRBE FCTSL OLDKU TBLEN OKBAL GBWTV FEUTS VJLVT MKOLZ LOIEG LDVTS TSETY WUCLO VUTSL BLJIV UFLTS LGVUL FKAKU RIFEU JEATS LOLEO LGWFS FAKIL OTEBI CLNTK UOLFR FALJV TLGIE UJTKT EAKWT NWTRK WAAPL TRKWO IEAZE PLBEF CNKWU JMKON KWUJU KDTSL IKKUL OVOKA ATSLI KKULO VGBEF CKMMS LITLN NLJJK DUEUJ EDERM OKGTS LTOWF CEUJD ETFSL JEIVT EFFLA LOETL JIGKK TSART WOULJ EUJWI VUPTS LNKDL ONAEU TEIFK ZLOSL EJLJK WTVUT KTSLM KKTSV AAIVU TKTSK WIEUJ IKMGV ALIKM UKTSV UPEIM EOEIB OKKCC ULDBW TIKGL DSLOL KWTTS LOLIL ZLUEU JESEA MSKWO IEDER DEIIK GLTSV UPEJL ITVUE TVKUT SETDK WAJBL DSETE XLUDE ITORV UPTKW UFKZL OBWTU KTVMB OKKCF KWAJW UFKZL OVTMV OITFC

Title: Crypto Challenge #2
Post by: zanco on June 07, 2005, 02:54:36 PM

Yeah!!!  (thumbsup)  I got it. Wasn't easy, but I did.

the Output looks like that:
maybe iveju stgot youfo oleda boutt hebad boypa rtimh erear entib eside syout oldme youju stwan ttobo rrowt histh oughi dstil llike tokno wwhyy ouwan ttobo rrowt hecar goint hetra ilerw asaba ttled amage dlynx itstu rretd estro yeddu ringt helas tskir mishw ithpl ymout hther estof thech assis badly damag edith adbee nboun dform etalr ecycl ingwh enbro okhad inter cepte ditab outth eonly possi bleus eheco uldth inkof forit wasas balla stech oshoo kherh eadim notre adyto trust youwi thall ourse crets yetyo ukeep provi dingt hings wenee dandw ellta lkabo utitb utnot today justt rustm eonth isone andil lbemu chmor eincl inedt otrus tyoui nthef uture shesh ookhe rhead backt oward thepo werpl antou tther esasc ooter backi nther ecess youca nuset ogetb ackto theco lonyr eluct antly hecli mbedo utass hesli dpast andin tothe seath erhan dsran overt hecon trols witha famil iarit yhedn everf eltwh endri vingw hereh adshe gotte nthec hance topra ctice thatl ooksg oodim outof hereh ekept hispe rchon thest epswa itwhe nwill yoube backs hecon sider edhis Quest ionfo ramom entbe forea nswer ingab outtw entyh oursf ormyb usine ssplu strav eltim ecall itthi rtyfi vehou rsfor tytop syous aidno bodyw illno ticet hetru ckism issin goper ation sthin ksits inthe garag etheg arage think sitsp artof thest arshi psalv ageco nvoyt hetru cktha tsact ually inthe convo ywasr otate douto foreh aulin gandw henyo ubrin gthis truck backi twill repla ceita slong asyou beatt hecon voyba ckthe rewon tbeap roble mbuti canth ideit forev ersam ewith thatj unker inthe bedsi nceth emine colon yscan dalth erear emuch close rtabs kepto nrecy cledi temsa ndtot alout putyo ullge tyour salva gebac kpoun dforp oundn owthe soone rirol lthes ooner imbac koffh estep peddo wnand awayf romth etruc kandw atche dasit accel erate dsmoo thlyt urned andus ingth epowe rplan tasco verhe adedo utint othef oothi llsin totho usand sofmi lesof nothi ngasf arasb rookk newbu tsome where outth erese venan dahal fhour saway wasso methi ngade stina tiont hatwo uldbe whata xenwa stryi ngtou ncove rbutn otifb rookc ouldu ncove ritfi rstck




When well spaced, it looks like that:
Maybe I've just got you fooled about the bad boy part; I'm here, arent I? besides you told me you just want to borrow this. Though I'd still like to know why you want to borrow the cargo. In the trailer was a battle damaged lynx; its turret destroyed during the last skirmish with plymouth the rest of the chassis badly damaged it had been bound for metal recycling when Brook had intercepted it about the only possible use he could think of for it was asbal last Echo shook her head I'm not ready to trust you with all our secrets, yet you keep providing things we need and we'll talk about it but not today just trust me on this one and I'll be much more inclined to trust you in the future. she shook her head back toward the power plant. out there's a scooter back in the recess you can use toget back to the colony. Reluctantly, he climbed out as she slid past and into the seat her hands ran over the controls with a familiarity he'd never felt when driving. where had she gotten the chance to practice? that looks good I'm out of here he kept his perch on the steps. wait, when will you be back? she considered his question for a moment before answering. about twenty hours for my business plus travel time call it thirty-five hours forty tops. you said nobody will notice the truck is missing. Operations thinks it's in the garage the garage thinks it's part of the starship salvage convoy the truck thats actually in the convoy was rotated out of ore hauling and when you bring this truck back it will replace it as long as you beat the convoy back there won't be a problem but I can't hide it forever same with that junker in the bed since the mine colony scandal there are much closer tabs kept on recycled items and total out put you'll get your salvage back pound for pound now the sooner I roll the sooner I'm back. off he stepped down and away from the truck and watched as it accelerated smoothly turned and using the power plant as cover, he aded out into the foot hills into thousands of miles of nothing as far as Brook knew but somewhere out there seven and a half hours away was something, a destination that would be what Axen was trying to uncover but not if brook could uncover it first. ck

 :)  

Title: Crypto Challenge #2
Post by: zanco on June 07, 2005, 03:00:39 PM

char frequencies:
chars:time(s) repeated:Percentage
       
A:                 72:    4.1026%
B:                44:    2.5071%
C:                 31:    1.7664%
D:                 41:    2.3362%
E:               129:    7.3504%
F:                 58:    3.3048%
G:                 31:    1.7664%
H:                  0:    0.0000%
I:                107:    6.0969%
J:                 64:    3.6467%
K:               159:    9.0598%
L:                189:   10.7692%
M:                 28:    1.5954%
N:                 28:    1.5954%
O:                101:    5.7550%
P:                 29:    1.6524%
Q:                  1:    0.0570%
R:                 44:    2.5071%
S:                105:    5.9829%
T:                193:   10.9972%
U:                104:    5.9259%
V:                102:    5.8120%
W:                 72:    4.1026%
Y:                  4:    0.2279%
X:                  2:    0.1140%
Z:                 17:    0.9687%


I wasn't thinking that "L" could be "e"  :find: ... that's mainly why it took me so long.

Title: Crypto Challenge #2
Post by: Hooman on June 08, 2005, 06:27:37 AM

Very impressive. Again, this was from the novellas, so you can look it up in there if anything does't quite fit. (Like "asbal last" should be "as balast", or where additional punctuation goes. But then, you probably can't get that quite right without the original.)

Letter frequencies was exactly the right way to start. There was a little more than just single letter frequencies however. The "e" thing may have been a bit confusing with this one. (For some reason I though I'd chosen the text so "e" was the most common letter). Anyways, it was only the second most common letter, so hopefully it didn't throw you off too much. I did however make sure the digraph and trigraph frequencies were helpful. Although, I doubt it occured to anyone to use them.

If you scan for the most common 2 and 3 letter sequences, you'll find that "TS" and "TSL" were the most common. These are expected to be "th" and "the". Even with the spacing and punctuation removed, you can still expect fairly good chances of this happening. Anyways, there were 34 occurances of "TSL" in the ciphertext, and the next most common trigraph only occured 14 times. (Which is about equivalent to a slap to the face  :P ). Also, "TS" occured 60 times, and the next most common digraph occured 57 times (and it was "SL"). Given that and "L" was the second most common letter, hopefully it wouldn't have been too hard to guess that "e" was "L" and not "T".

Also, it would have been important to look for repeated letters. Some of the most common repeated letters were "AA" (14 occurances), "TT", and "KK" (both at 13 occurances).


Well, I'd hoped that anyone looking at trigraphs and digraphs would have been able to guess the letters used for "the" fairly easily. It got a bit harder after that, but once a few more letters are filled in, it should have gotten easier. But again, good job on this one. Did you really break it using only single letter frequencies?

Another one?  :)
 

Title: Crypto Challenge #2
Post by: zanco on June 08, 2005, 11:58:26 AM

Quote

Did you really break it using only single letter frequencies?

Well, I mostly used single letter frequencies and lots, lots of guesses, but once I figured "L" was "e" and "T" was "t," it was easier to find the other letters, for example the "the" that you were talking about. I looked a bit for reapeted letters, but didn't quite focuse on them. I was lucky enough to guess what "ing" was. That helped me a lot. Thanks for the fun.

Quote

Another one?

Sure! I think I'm getting the hang of this thing. Make it harder.