Probably a code?

Is the regularity shown in this encoded message noise or structure?

Problem

When cracking text-based codes, a first step is often to look for repeated strings of characters resulting from structure in the underlying cypher-text. This can give a way in to cracking the code.

 

Alison and Steve are considering the following coded message:

 

vrucseviffsrzpvekpqmyfvfvarvfhfzecsxzvvorjbtlrkaqmcvbgyfsct

nuznglyrkqsqewtauvzpievmblcciabcfvofpymgrfnpkjuszcjrjuaur

idgznelhpycaoljzbjkrcqioguwavhlvflejbcuqkpkzsvmnpaxivovjjt

lrqmyovtpjhfkzccrctgksiwoauvzgnvfvuabnitkfnpkjuziohqmipjv

eoipivaolnwwtlgravlbwbjvfvqefpcqolfzvuwviqvlqsgvovjekuqfnr

ybdqulzplcfqimctfsmevzvuqyrwmtcrebcuqmqxpqzbtfvedcpak

wdlcvzubnumfaurbvorgwnlvjbjlfvivvswzqzgrvfkrjwnhgzwppgv

dgycimulakakafvthabdgktnxqphgzwphfkpgyrxqqubwjghhkgcu

qumnptybvorimohexitlgkpgzhequmbimxlemqupocmkafszqhqu

qurwlavzxzzvpaxbjlufzkgbeipkqznhbfzvihcvzrlglinzccmpkblzv

orimhvenqvolfctsrrdgtljquariqypycxwaffugaelavpagzgjruqpna

rdknnkwtzgymtlfewyhauntvfkitlorvkzuvlcuqjiksveoqcriiehyda

ghjvucfovecmgvlvvncipkflzrhfjqpnveequqvzuhauqpirrcvfrmm

tfevokvayqvoribqkvjkqcrimfvakpgonsqvhocmisbsmkafgzqkhtb

kvajipksvivbevaohlsmypgywwaroiowyviuauvxjlafugunfnvorym

ccretaibuqgzhelqbokmfslrzgpakpqzrlvfpftwxlevluvyzbwkrjejhg

diaubkjglkgmearuqphpfcpaepwhlgvzphycqiogrqohlkpgyruqujb

mmtauvequqiwwzcfegyjyqeonkbthpkavoremgkyvipkzrgtltltcar

rbjvhjipkpvtgzgzinvojmtcnkqqufkpcaevywpevwpslkpkzifgcnrk

wtlaumtauvqtzrvukutvkelakzkjvkqgzpfvupfkmpasfzgcriquonct

uhgzivlzpitkrebebezwupgpekaukpgzvxpvvsrxcygfnvornwtsqem

xlesmhvevdkzvkmfhauucfgimckncipkavdgyovnqyrzuryvebgkop

bjlsfwvvsdipauvaghevualakqelzvvvznelvorpitlflnhppzmpagfkq

udlmthycnghefnfhaxmtveumcaurvfabzvfbpvugabtwotrekgauz

anhofzkvhjdqfnxmypgybjlwfgcjuztfmrvtuduvvjlrdjcyxjqphyzb

vsrswcajzbjovjpqsvuiatnkmuvarvgecvlkavfvqmqzaevivzabcyqu

unkqxlezdgyolbubcgwupaxinsgymulpfvllpkctlfkwdlsrtullfceha

ewvjbebgzgkpgpavavpzrjnlovvgmvkejppyquonctevawmtvartn

tneskuqkwvorciuatvvgynkqquoplkzpfdgyveocwnjacnremcygy

mrvyvbqaufagjblvvyvvavvevieojyqeonkxtlfvvvzbdipfzfvvofrzg

yrhckzvkmqyopiujribcpazviauvagjevbqmgymohtemvduzkjpsr

bcsygwuzvstgjnewpslsmgmsvkvlqsgcuhelgygrskutjceonjukur

 

Alison computes the frequency of each letter, finding these results:

 

abcdefghijklmnopqrstuvwxyz
855572227377854861589077615555878078415894166 44215380

 

After some fiddling around on a spreadsheet, Steve notices that there are seven repeated strings of 5 letters, highlighted as shown below:

 

Image
Probably a code?

 

 

Steve dismisses this as coincidence, saying "I would guess that these repeated 5-letter sequences  are consistent with randomly generated text based on these frequencies of letters". Alison is not convinced and thinks that this structure of 5 letter sequences would not likely occur randomly for these frequencies of letters.

 

Investigate.

 

Challenge: Crack the code, regardless of who is right!