Abstract. We consider the security of message authentication code (MAC) algorithms, and the construction of MACs from fast hash functions. A new forgery attack applicable to all iterated MAC algorithms is described, the rst known such attack requiring fewer operations than exhaustive key search. Existing methods for constructing MACs from hash functions, including the secret pre x, secret su x, and envelope methods, are shown to be unsatisfactory. Motivated by the absence of a secure, fast MAC algorithm not based on encryption, a new generic construction (MDx-MAC) is proposed for transforming any secure hash function of the MD4-family into a secure MAC of equal or smaller bitlength and comparable speed.
REF proposed a generic construction (MDx-MAC) for transforming any secure hash function of the MD4-family into a secure MAC.
MDx-MAC and Building Fast MACs from Hash Functions
In Crypto 95
Computer Science