Recently the Foreign Ministry of Estonia published its annual report titled In the international security environment of Estonia. At the end of report, there is a nice puzzle that invites the readers to decipher and find key for two ciphertext that are received by one of its operator. This puzzle was circulated in couple of internal mailing lists where the poster was kind enough to translate the puzzle in English for non-Estonian speakers.

I will write another blog post later on that will describe the walkthrough on solving this puzzle.

The puzzle

Signal intelligence was able to capture an encrypted message: SDZROZDBITGNUMYNSF.

However, the receiver was unable to decrypt the message and the message was transmitted again: YHDRCRLBUTIPUCMFGF


  1. What was content of the message?
  2. What key was used for the encryption?


The solutions can be sent to info [at] with subject line as Nuputamis├╝lesanne.

Enjoy breaking it :)