Recording medium tag generator, tag verification apparatus, communication system, tag generation method, and tag verification method

摘要

Tag generation apparatus of the present invention, a first intermediate by applying a hash unit that generates a hash value by applying a hash function to the message (12), a cryptographic function with the key to the first random number independent of the message masked encryption unit for generating an intermediate second variable by applying random encryption unit for generating a variable (14), a cryptographic function with the second key to the sum of the hash value and the random number (15) , a tag generator for generating a tag value contained in the bits of the predetermined number of bits is the number of bits less than the random number extracted from the exclusive OR of the intermediate variable and the second intermediate variable and the first (16) I have a.