TY - GEN

T1 - Tweakable enciphering schemes from hash-sum-expansion

AU - Minematsu, Kazuhiko

AU - Matsushima, Toshiyasu

PY - 2007/12/1

Y1 - 2007/12/1

N2 - We study a tweakable blockcipher for arbitrarily long message (also called a tweakable enciphering scheme) that consists of a universal hash function and an expansion, a keyed function with short input and long output. Such schemes, called HCTR and HCH, have been recently proposed. They used (a variant of) the counter mode of a blockcipher for the expansion. We provide a security proof of a structure that underlies HCTR and HCH. We prove that the expansion can be instantiated with any function secure against Known-plaintext attacks (KPAs), which is called a weak pseudorandom function (WPRF). As an application of our proof, we provide efficient blockcipher-based schemes comparable to HCH and HCTR. For the double-block-length case, our result is an interesting extension of previous attempts to build a doubleblock-length cryptographic permutation using WPRF.

AB - We study a tweakable blockcipher for arbitrarily long message (also called a tweakable enciphering scheme) that consists of a universal hash function and an expansion, a keyed function with short input and long output. Such schemes, called HCTR and HCH, have been recently proposed. They used (a variant of) the counter mode of a blockcipher for the expansion. We provide a security proof of a structure that underlies HCTR and HCH. We prove that the expansion can be instantiated with any function secure against Known-plaintext attacks (KPAs), which is called a weak pseudorandom function (WPRF). As an application of our proof, we provide efficient blockcipher-based schemes comparable to HCH and HCTR. For the double-block-length case, our result is an interesting extension of previous attempts to build a doubleblock-length cryptographic permutation using WPRF.

KW - HCH

KW - HCTR

KW - Mode of operation

KW - Weak pseudorandom function

UR - http://www.scopus.com/inward/record.url?scp=38349022443&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=38349022443&partnerID=8YFLogxK

M3 - Conference contribution

AN - SCOPUS:38349022443

SN - 9783540770251

T3 - Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)

SP - 252

EP - 267

BT - Progress in Cryptology - INDOCRYPT 2007 - 8th International Conference on Cryptology in India, Proceedings

T2 - 8th Annual International Conference on Cryptolology in India, INDOCRYPT 2007

Y2 - 9 December 2007 through 13 December 2007

ER -