Hyde & Rugg:

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The D'Agapeyeff Cipher

The D’Agapeyeff Cipher is a classic uncracked code, dating from 1939. Gordon has worked with Robert Matthews, Stephen Antrobus and Gavin Taylor on this problem, and this work has identified some promising leads.


The D'Agapeyeff Cipher in brief:
  • Created in 1939 by Alexander D’Agapeyeff, a cartographer (map maker)
  • Was a challenge/test at the end of an introductory book on codes
  • Looks like a classic modern cipher, consisting of groups of 5 numbers
  • D’Agapeyeff forgot how he had coded it
  • The cipher has never been decoded
  • There are suspicions that D’Agapeyeff made a mistake with the encoding
Gordon’s collaboration with Robert Matthews, Steven Antrobus & Gavin Taylor, in brief:
  • British researcher Robert Matthews suggested that the cipher might be crackable by using genetic algorithm (GA) software.
  • One of Gordon’s students, Steven Antrobus, showed that this method had promise.
  • Another of Gordon’s students, Gavin Taylor, has also worked on the cipher, focusing on possible areas of human error. Gavin and Gordon have written a series of articles about the results on the Hyde & Rugg blog (links below).
  • Gavin found a significant proofreading error in one of the worked examples in D’Agapeyeff’s book. This is consistent with the theory that the D’Agapeyeff Cipher contains a mistake in its coding or transcription, preventing it from being cracked.


Articles and links about the D'Agageyeff Cipher



Image: The D'Agapeyeff Cipher in the First Edition