In 1987, Chris Cole posted a message to the sci.crypt Usenet group:

When I was a graduate student at Caltech, Professor Feynman showed me three samples of code that he had been challenged with by a fellow scientist at Los Alamos and which he had not been able to crack. I also was unable to crack them. I now post them for the net to give it a try.

The first, marked “Easier,” was this:

MEOTAIHSIBRTEWDGLGKNLANEA INOEEPEYSTNPEUOOEHRONLTIR OSDHEOTNPHGAAETOHSZOTTENT KEPADLYPHEODOWCFORRRNLCUE EEEOPGMRLHNNDFTOENEALKEHH EATTHNMESCNSHIRAETDAHLHEM TETRFSWEDOEOENEGFHETAEDGH RLNNGOAAEOCMTURRSLTDIDORE HNHEHNAYVTIERHEENECTRNVIO UOEHOTRNWSAYIFSNSHOEMRTRR EUAUUHOHOOHCDCHTEEISEVRLS KLIHIIAPCHRHSIHPSNWTOIISI SHHNWEMTIEYAFELNRENLEERYI PHBEROTEVPHNTYATIERTIHEEA WTWVHTASETHHSDNGEIEAYNHHH NNHTW

Jack Morrison of NASA’s Jet Propulsion Laboratory had it solved the next day: “It’s a pretty standard transposition: split the text into 5-column pieces, then read from lower right upward.” This yields the opening of Chaucer’s Canterbury Tales:

WHANTHATAPRILLEWITHHISSHOURESSOOTET HEDROGHTEOFMARCHHATHPERCEDTOTHEROOT EANDBATHEDEVERYVEYNEINSWICHLICOUROF WHICHVERTUENGENDREDISTHEFLOURWHANZE PHIRUSEEKWITHHISSWEETEBREFTHINSPIRE DHATHINEVERYHOLTANDHEETHTHETENDRECR OPPESANDTHEYONGESONNEHATHINTHERAMHI SHALVECOURSYRONNEANDSMALEFOWELESMAK ENMELODYETHATSLEPENALTHENYGHTWITHOP ENYESOPRIKETHHEMNATUREINHIRCORAGEST HANNELONGENFOLKTOGOONONPILGRIM

But the other two ciphers have never been solved, despite 30 years of trying. Here they are:

#2 (“Harder”)

XUKEXWSLZJUAXUNKIGWFSOZRAWURORKXAOS LHROBXBTKCMUWDVPTFBLMKEFVWMUXTVTWUI DDJVZKBRMCWOIWYDXMLUFPVSHAGSVWUFWOR CWUIDUJCNVTTBERTUNOJUZHVTWKORSVRZSV VFSQXOCMUWPYTRLGBMCYPOJCLRIYTVFCCMU WUFPOXCNMCIWMSKPXEDLYIQKDJWIWCJUMVR CJUMVRKXWURKPSEEIWZVXULEIOETOOFWKBI UXPXUGOWLFPWUSCH

#3 (“New Message”)

WURVFXGJYTHEIZXSQXOBGSVRUDOOJXATBKT ARVIXPYTMYABMVUFXPXKUJVPLSDVTGNGOSI GLWURPKFCVGELLRNNGLPYTFVTPXAJOSCWRO DORWNWSICLFKEMOTGJYCRRAOJVNTODVMNSQ IVICRBICRUDCSKXYPDMDROJUZICRVFWXIFP XIVVIEPYTDOIAVRBOOXWRAKPSZXTZKVROSW CRCFVEESOLWKTOBXAUXVB

Feynman, apparently, couldn’t break them either.