A Differential Meet-in-the-Middle Attack on the Zip cipher

Michael Stay

Paper 2020/983

A Differential Meet-in-the-Middle Attack on the Zip cipher

Michael Stay

Abstract

We report the successful recovery of the key to a Zip archive containing only two encrypted files. The attack improves on our 2001 ciphertext-only attack, which required five encrypted files. The main innovations are a new differential meet-in-the-middle attack for the initial stages and the use of lattice reduction to recover the internal state of the truncated linear congruential generator.

Metadata

Available format(s): PDF
Category: Secret-key cryptography
Publication info: Preprint. MINOR revision.
Keywords: Cryptanalysis stream ciphers
Contact author(s): stay @ pyrofex net
History: 2020-08-18: received
Short URL: https://ia.cr/2020/983
License: CC BY

BibTeX

@misc{cryptoeprint:2020/983,
      author = {Michael Stay},
      title = {A Differential Meet-in-the-Middle Attack on the Zip cipher},
      howpublished = {Cryptology {ePrint} Archive, Paper 2020/983},
      year = {2020},
      url = {https://eprint.iacr.org/2020/983}
}