SafeDeflate: compression without leaking secrets

Michał Zieliński

Paper 2016/958

SafeDeflate: compression without leaking secrets

Michał Zieliński

Abstract

CRIME and BREACH attacks on TLS/SSL leverage the fact that compression ratio is not hidden by encryption to recover content of secrets. We introduce SafeDeflate---a modification of a standard Deflate algorithm which compression ratio does not leak information about secret tokens. The modification is compatible with existing Deflate and gzip decompressors. We introduce a model in which attacker can obtain ciphertexts of arbitrary compressed plaintext containing secret values. Then we prove that SafeDeflate is secure in this model.

Metadata

Available format(s): PDF
Category: Cryptographic protocols
Publication info: Preprint. MINOR revision.
Keywords: compression information leak CRIME
Contact author(s): michal @ zielinscy org pl
History: 2016-10-04: received
Short URL: https://ia.cr/2016/958
License: CC BY

BibTeX

@misc{cryptoeprint:2016/958,
      author = {Michał Zieliński},
      title = {{SafeDeflate}: compression without leaking secrets},
      howpublished = {Cryptology {ePrint} Archive, Paper 2016/958},
      year = {2016},
      url = {https://eprint.iacr.org/2016/958}
}