Incremental cryptography and security of public hash functions

Abstract

An investigation of incremental algorithms for crytographic functions was initiated. The problem, for collision-free hashing, is to design a scheme for which there exists an efficient “update” algorithm: this algorithm is given the hash function H, the hash h = H(M) of message M and the “replacement request” (j, m), and outputs the hash H(M(j, m)) of the modified message. Ideally, the update time should depend only on the block size b and the underlying security parameter k, and not on the length of the message. JONAMP Vol. 11 2007: pp. 467-474