Unicity distance of the Zodiac-340 cipher

Joachim von zur Gathen

Paper 2021/1620

Unicity distance of the Zodiac-340 cipher

Joachim von zur Gathen

Abstract

In December 2020, David Oranchak, Jarl Van Eycke, and Sam Blake solved a 51-year old mystery: the Zodiac cipher of 340 symbols. Blake (2021) explains their solution. The correctness of their solution has not been seriously doubted, and here we give a further argument in its favor: the unicity distance of the cipher's system is at most 152.

Metadata

Available format(s): PDF
Category: Secret-key cryptography
Publication info: Preprint. MINOR revision.
Keywords: historical cryptography Zodiak cipher cryptanalysis unicity distance
Contact author(s): gathen @ bit uni-bonn de
History: 2021-12-14: received
Short URL: https://ia.cr/2021/1620
License: CC BY

BibTeX

@misc{cryptoeprint:2021/1620,
      author = {Joachim von zur Gathen},
      title = {Unicity distance of the Zodiac-340 cipher},
      howpublished = {Cryptology {ePrint} Archive, Paper 2021/1620},
      year = {2021},
      url = {https://eprint.iacr.org/2021/1620}
}