A New (n, 2n) Double Block Length Hash Function Based on Single Key Scheduling

In this paper we propose a double block length hash function called MR-MMO. Our scheme satisfies two calls of (n, 2n) block cipher and can compress 3n bits to 2n bits (n = 128 bits). The Collision Resistance (CR) and Preimage Resistance (PR) of MR-MMO are respectively 2^126.70 and 2^252.5. Surprisingly, the collision security bound of our scheme is the best in compare with other existing schemes. We use a single key scheduling for each compression function which is great in respect of cost and time. Additionally, it can be said that the proof technique of Weimar-DM, Tandem-DM, Hirose-DM are based on Ideal Cipher Model (ICM) while we use Weak Cipher Model (WCM) tool. Davies Meyer (DM) mode is used in the above all schemes, we also made a change using Matyas Meyer Oseas (MMO) mode. It is also obvious that the proof technique of our scheme is very simple, straightforward and easy to understand.