TAG GENERATING DEVICE, TAG VERIFICATION DEVICE, COMMUNICATION SYSTEM, TAG GENERATING METHOD, TAG VERIFICATION METHOD, AND RECORDING MEDIUM

摘要

Disclosed is a tag generating device which comprises: a hash unit (12) for applying a hash function to a message to generate a hash value; a random number encryption unit (14) for applying an encryption function having a first key to the message and independent random numbers to generate a first intermediate variable; a masked encryption unit (15) for applying an encryption function having a second key to the sum of the random numbers and the hash value to generate a second intermediate variable; and a tag generating unit (16) for generating the value included in the bits of a predetermined number of bits which is not more than the number of bits of random numbers extracted from the exclusive OR of the first intermediate variable and the second intermediate variable as a tag.