The encryption is: TN HF QX BO TN BO WG VY QX TN UP IE TN TN QX BO

I will tell you that it is a word.

Clue one:

4 Bravo

Clue two:

Edition No. 819

Clue three:


Clue four:



(I will add more clues if it goes unsolved for too long)

  • $\begingroup$ @ManishKundu why would it be? $\endgroup$ – Quintec Feb 6 '18 at 16:09
  • $\begingroup$ In case this saves anyone else some time, there don't appear to be any (common) 16-letter words having a double letter two places from the end the same as the first letter, except for a bunch of S words, all of which also have an S as the last letter (and these are questionable anyway; things like "stupendousnesses"). It might be a pretty uncommon word, a proper noun, not English... $\endgroup$ – Guest Feb 8 '18 at 15:09
  • 1
    $\begingroup$ This is probably a book cipher, but the chances i'll find the book and also have the book are slim :( $\endgroup$ – Quintec Feb 8 '18 at 17:30
  • $\begingroup$ @thecoder16, you'd think that knowing what kind of cipher it is would be just about the most valuable hint you could give. That, and a long enough encrypted message that letters/digraphs/etc. would have some statistical significance. I tried posting a puzzle like that the other day, but was told it was no good because there was "no hint," even though it said right in the title it was a symmetric keyword cipher, and the encrypted message was a good four lines long. Still can't quite figure this site out... $\endgroup$ – Guest Feb 8 '18 at 17:45
  • 2
    $\begingroup$ @North the issue with the DRYAD cipher is that you need a full code sheet - which might be what the other clues are leading to $\endgroup$ – Nobody Feb 9 '18 at 6:11

Is the answer:


Elaboration based on clues:

Clue 3 and 4:

DRYAD: A paper based cryptosystem used by the US. But, looking into the methods for deciphering a message, it appears that pairs like BO are invalid since O cannot be in the second place in the pair (I and O do not correspond to any columns in DRYAD cipher sheets). This lead me to research the British alternative BATCO, which ends up working with the given ciphertext and following clues.

Clue 2:

Edition No. 819: Thankfully, this one was quite simple, as the sample cipher sheet on the BATCO Wikipedia page was labeled as Edition No. 819. Therefore, I'll be using this sheet to decipher the message.

Clue 1:

4 Bravo: This will be the key we will use to decipher the BATCO message. In the topmost row, we find the number 4, then in that column we find the letter B, which corresponds to Bravo. The row that this corresponds with will be the row that we will use to decipher the message.

Deciphering the message:

We can see that the pairs of letters found in the ciphertext are also found in the row we found in the above steps. This makes me believe we are on the right track. From here, we go through the row finding the pairs of letters that match with the ciphertext, and find the bolded number in the topmost row and save those numbers for later. The numbers we find end up being 3 1 2 8 3 8 4 5 2 3 7 6 3 3 2 8. We now group these numbers in pairs of two, so the result would be 31 28 38 45 23 76 33 28. With these pairs, we find the corresponding row and column found in the bottom left box in the cipher sheet, with the first number corresponding to the row and the second number corresponding to the column. 31 corresponds to K, 28 corresponds to E, 38 corresponds to T, etc. Continuing this, we get our final result of KETAMINE.

  • $\begingroup$ Wow! Nice job! Looks correct. What is ketamine though? $\endgroup$ – Prince North Læraðr Feb 16 '18 at 20:48
  • $\begingroup$ @North It appears to be a drug used for as an anesthetic or sedative in the medical world. Source: en.wikipedia.org/wiki/Ketamine $\endgroup$ – MrPublic Feb 16 '18 at 23:35

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