The PRF Security of Compression-Function-Based MAC Functions in the Multi-User Setting

Shoichi HIROSE  

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E102-A   No.1   pp.270-277
Publication Date: 2019/01/01
Online ISSN: 1745-1337
DOI: 10.1587/transfun.E102.A.270
Type of Manuscript: PAPER
Category: Cryptography and Information Security
compression function,  MAC,  pseudorandom function,  multi-user security,  vector-input PRF,  

Full Text: FreePDF(670.8KB)

A compression-function-based MAC function called FMAC was presented as well as a vector-input PRF called vFMAC in 2016. They were proven to be secure PRFs on the assumption that their compression function is a secure PRF against related-key attacks with respect to their non-cryptographic permutations in the single user setting. In this paper, it is shown that both FMAC and vFMAC are also secure PRFs in the multi-user setting on the same assumption as in the single user setting. These results imply that their security in the multi-user setting does not degrade with the number of the users and is as good as in the single user setting.