MESSAGE AUTHENTICATOR GENERATOR, MESSAGE AUTHENTICATOR VERIFICATION APPARATUS, MESSAGE AUTHENTICATOR GENERATING METHOD, MESSAGE AUTHENTICATOR VERIFICATION METHOD, PROGRAM, AND RECORDING MEDIUM

摘要

PROBLEM TO BE SOLVED: To provide a message authentication code having safety exceeding a birthday limit. SOLUTION: A message authenticator generator includes a key padding means, a DIL means, a cAU means, and a pseudo random number means. The key padding means outputs (L+1) c-bit (c is a predetermined integer) keys K1, ..., KL, K'. The DIL means generates L (L is an integer of 2 or more) data D1, ..., DLof multiples of b-bit (b is a predetermined integer) from data M by using a DIL function. The cAU means determines an intermediate variable yiof c-bit for each datum Di(i is an integer between 1 and L) by using a cAU function and a key Ki. The pseudo random number means determines a message authenticator tag from L intermediate variables y1, ..., yLby using a pseudo random number family of functions. COPYRIGHT: (C)2009,JPO&INPIT