Analysis of the WinZip encryption method

Tadayoshi Kohno

Paper 2004/078 Original: eprint.iacr.org/2004/078 ↗

Analysis of the WinZip encryption method

Tadayoshi Kohno

Abstract

WinZip is a popular compression utility for Microsoft Windows computers, the latest version of which is advertised as having "easy-to-use AES encryption to protect your sensitive data." We exhibit several attacks against WinZip's new encryption method, dubbed "AE-2" or "Advanced Encryption, version two." We then discuss secure alternatives. Since at a high level the underlying WinZip encryption method appears secure (the core is exactly Encrypt-then-Authenticate using AES-CTR and HMAC-SHA1), and since one of our attacks was made possible because of the way that WinZip Computing, Inc.~decided to fix a different security problem with its previous encryption method AE-1, our attacks further underscore the subtlety of designing cryptographically secure software.

Metadata

Available format(s): PDF
Category: Applications
Publication info: Preprint.
History: 2004-05-09: last updated; 2004-03-14: published
Short URL: https://ia.cr/2004/078
License: https://creativecommons.org/licenses/by/4.0/

BibTeX

@misc{cryptoeprint:2004/078,
      author = {Tadayoshi Kohno},
      title = {Analysis of the WinZip encryption method},
      howpublished = {Cryptology {ePrint} Archive, Paper 2004/078},
      year = {2004},
      url = {https://eprint.iacr.org/2004/078}
}