Stefano Lonardi

Assistant Professor, Computer Science & Engineering

University of California, Riverside, CA 92521

LZS'77 (M. J. Atallah and S. Lonardi)

The massive distribution capability allowed by Internet makes it increasingly important to devise new methods to ensure authenticity. Nowadays it is common practice to distribute documents in compressed form. In this project, we propose a simple variation on the classic LZ-77 algorithm that allows one to hide within enough information to warrant the authenticity of the compressed document. The design is based on cryptographically-secure pseudo-random generators, in such a way that the hidden data cannot be retrieved in a reasonable amount of time by an attacker unless the secret key is known. The embedding is totally transparent: since it can still be decompressed by the original LZ-77 algorithm, to a "casual eavesdropper" the augmented compressed file appears perfectly normal. Preliminary experiments show also the degradation in compression due to the embedding is almost negligible.

M.J.Atallah, S.Lonardi, "Authentication of LZ-77 compressed data", Proceedings of the ACM Symposium on Applied Computing (SAC'03), pp.282-287, Melbourne, FL, March 2003. BibTex entry

Slides of "Authentication of LZ-77 compressed data", (SAC'03), Melbourne, FL, March 2003.

Download gzipS

Unzip, and untar, then read the file GZIPS.README for instructions

Contact Stefano Lonardi (stelo AT cs.ucr.edu) for questions and problems

The licencing of this software follows the licencing of the original gzip

(C) 2003, The Regents of the University of California