Improved security analyses for CBC MACs Conference Paper


Author(s): Bellare, Mihir; Pietrzak, Krzysztof; Rogaway, Phillip
Title: Improved security analyses for CBC MACs
Title Series: LNCS
Affiliation
Abstract: We present an improved bound on the advantage of any q-query adversary at distinguishing between the CBC MAC over a random n-bit permutation and a random function outputting n bits. The result assumes that no message queried is a prefix of any other, as is the case when all messages to be MACed have the same length. We go on to give an improved analysis of the encrypted CBC MAC, where there is no restriction on queried messages. Letting m be the block length of the longest query, our bounds are about mq2/2n for the basic CBC MAC and mo(1)q2/2n for the encrypted CBC MAC, improving prior bounds of m2q2/2n. The new bounds translate into improved guarantees on the probability of forging these MACs.
Conference Title: CRYPTO: International Cryptology Conference
Volume: 3621
Conference Dates: August 14-18, 2005
Conference Location: Santa Barbara, CA, USA
Publisher: Springer  
Date Published: 2005-09-12
Start Page: 527
End Page: 545
Copyright Statement: ⓒ International Association for Cryptologic Research 2005
Sponsor: Pietrzak was supported by the Swiss National Science Foundation, project No. 200020-103847/1.
DOI: 10.1007/11535218_32
Open access: no
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