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

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.