A New Double-Block-Length Hash Function Using Feistel Structure

摘要

We propose new double-block-length hash functions. Our approach for constructing collision-resistant double-block-length hash functions is to convert a blockcipher E with n-bit block length and 2n-bit key length to a 3-round Feistel cipher E~* with 2n-bit block length, and then to embed E~* in PGV compression functions. We prove that 12 hash functions with the group-1 PGV compression functions in which E~* is embedded are collision-resistant in the ideal cipher model. Furthermore, since our hash functions have the hash rate 2/3, they are more efficient than any other existing double-block-length hash functions in terms of the number of blockcipher calls required for processing messages.