The Design and Analysis of a Hash Ring-iterative Structure

This paper proposes a new type of hash iterative structure ─ the ring-iterative structure with feedback which is subdivided into the single feedback ring iteration and the multiple feedback ring iteration, namely SFRI and MFRI. The authors prove that if f is a secure one-way compression function, the security of the MFRI structure is greater than that of the classical MD iterative structure, analyze the resistance of MFRI, which is from the joint event on message modification, the endless loop on message modification and the incompatibility of the sufficient conditions, to the multi-block differential collision attack, and argue the ineffectiveness of the D-way second preimage attack on MFRI. The paper discusses the time and space expenses of MFRI, and points out the advantage of MFRI over the tree-iterative structure and the zipper-iterative structure.