Title
Zmac(+)- An Efficient Variable-Output-Length Variant Of Zmac
Abstract
There is an ongoing trend in the symmetric-key cryptographic community to construct highly secure modes and message authentication codes based on tweakable block ciphers (TBCs). Recent constructions, such as Cogliati et al.'s HAT or Iwata et al.'s ZMAC, employ both the n-bit plaintext and the t-bit tweak simultaneously for higher performance.This work revisits ZMAC, and proposes a simpler alternative finalization based on HAT. As a result, we propose HTTBC, and call its instantiation with ZHash as a hash function ZMAC(+). Compared to HAT, ZMAC(+) (1) requires only a single key and a single primitive. Compared to ZMAC, our construction (2) allows variable, per-query parametrizable output lengths. Moreover, ZMAC(+) (3) avoids the complex finalization of ZMAC and (4) improves the security bound from O (sigma(2)/2(n+min(n,t))) to O (q/2(n) + (q + sigma )/2(n+min(n,t))) while retaining a practical tweak space.
Year
DOI
Venue
2017
10.13154/tosc.v2017.i4.306-325
IACR TRANSACTIONS ON SYMMETRIC CRYPTOLOGY
Keywords
DocType
Volume
Message authentication code, tweakable block cipher, provable security
Journal
2017
Issue
Citations 
PageRank 
4
0
0.34
References 
Authors
0
2
Name
Order
Citations
PageRank
Eik List111113.70
Mridul Nandi235748.09