The Catokwacopa cryptograms

In the book The Agony Column Codes & Ciphers, Jean Palmer – the pseudonym of codebreaker Tony Gaffney – presents more than a thousand encrypted newspaper advertisements from Victorian England. Many of these messages are love letters. Gaffney solved many of these cryptograms himself, and the book includes their solutions. Others, however, are still waiting to be deciphered.

 

Two advertisements, twelve days apart

Among the unsolved examples are two advertisements published in the Evening Standard in May 1875. The first one appeared on May 8, 1875.

Here’s a transcript:

W. Str 53. Catokwacopa. Olcabrokorlested. Coomemega. Sesipyyocashostikr. Rep. – Itedconlec mistrl. – Hfsclam 54, 3 caselcluchozamot. 1. 6. 9. Mopredisco. Contoladsemot. Iadfilisat. Qft. Cagap. Balmnopsemsov. Ap. 139. – Hodsam 55, 6. Iopotonrogfimsecharsenr. Tolshr. Itedjolec. mistrl. – Ding Declon. Ereflodbr.

Twelve days later, on May 20, a second advertisement appeared.

Here’s a transcript:

W. – Umem 18. Poayatlgerty. Dpeatcnrftin. Nvtinrdn. Dmlurpinrtrcamur. Etd. – Atndngtnsurs. Otenpu. – Eftdorshpxn. 18. Ndtsfindseseo. Cotegr Tavlysdinlge. Ngtndusdcndo. Edrstneirs. Ui, Ndted. iolapstedtioc. A. P. 138. – Yxn. 18. 18. Wtubrfftrstendinhofsvmnr. Dily. – Atdwtsurs. Oatvpu. – Y Arati. Rileohmae. – This will be intelligible if read in connection with my communication published in this column on the 8th inst.

I call these messages the “Catokwacopa cryptograms” because of the first word in the first ad.

 

A transposition cipher?

The final sentence of the second Catokwacopa cryptogram is written in plain English:

This will be intelligible if read in connection with my communication published in this column on the 8th inst.

This appears to be an important clue.

The Catokwacopa cryptograms look quite different from many of the other encrypted advertisements in Gaffney’s book. Words such as Catokwacopa, Olcabrokorlested, and Coomemega are pronounceable. That is unusual for letter-based substitution ciphers. My first impression was therefore that this might be a transposition cipher. I performed a frequency analysis using CrypTool 2:

The frequency distribution looks remarkably similar to that of ordinary English text. As expected, this is consistent with a transposition cipher.

The most obvious idea is that the two advertisements somehow have to be mixed together. For example, we could take: letter 1 from advertisement 1, letter 1 from advertisement 2, letter 2 from advertisement 1, letter 2 from advertisement 2, … Perhaps the process is reversed, or perhaps the texts need to be arranged in columns before being read in a particular order.

After my blog posts about the Catokwacopa cryptograms, several readers – Thomas, Lance Estes, Dave, and JA – looked more closely at this hypothesis. It does seem to make sense. So far, however, nobody has managed to turn the idea into a complete solution.

 

Can the letter Q help?

Thomas pointed out another potentially useful clue: the letter Q. The first advertisement contains a Q:

… Iadfilisat. Qft. Cagap. …

In English, Q is almost invariably followed by U. If the ciphertext is produced by transposing two texts, perhaps the Q can tell us something about where the corresponding U should be located. Suppose, for example, that the two advertisements are interleaved. We could look at the position of the Q in the first advertisement and determine which character from the second advertisement would occupy the corresponding position in the reconstructed text. If that character turns out to be U—and if the surrounding characters begin to form recognizable English—that would be a strong indication that the interleaving hypothesis is correct. Unfortunately, this approach hasn’t led to the solution yet.

 

Still unsolved

At this point, we have several intriguing pieces of evidence, but no definitive solution. The Catokwacopa advertisements are a wonderful example of how a short newspaper puzzle from 1875 can still challenge cryptologists more than 150 years later.

 

Literature

Klaus Schmeh, Elonka Dunin: Codebreaking: A Practical Guide. No Starch Press 2023

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