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Paper: Stronger Security Bounds for OMAC, TMAC and XCBC

Authors: Tetsu Iwata Kaoru Kurosawa URL: http://eprint.iacr.org/2003/082 Search ePrint Search Google OMAC, TMAC and XCBC are CBC-type MAC schemes which are provably secure for arbitrary message length. In this paper, we present a more tight upper bound on ${\tt Adv}^{\sf mac}$ for each scheme, where ${\tt Adv}^{\sf mac}$ denotes the maximum success (forgery) probability of adversaries. Our bounds are expressed in terms of the \textit{total length} of all queries of an adversary to the MAC generation oracle while the previous bounds are expressed in terms of the \textit{maximum length} of each query. In particular, a significant improvement occurs if the lengths of queries are heavily unbalanced.
BibTeX
@misc{eprint-2003-11798,
title={Stronger Security Bounds for OMAC, TMAC and XCBC},
booktitle={IACR Eprint archive},
keywords={secret-key cryptography / modes of operation, message authentication codes, block cipher, provable security.},
url={http://eprint.iacr.org/2003/082},
note={ iwata@cis.ibaraki.ac.jp 12172 received 30 Apr 2003},
author={Tetsu Iwata and Kaoru Kurosawa},
year=2003
}