| abstract |
Provided are a message authentication device, a message authentication method, a message authentication program and a recording medium therefor, which combine block ciphers and their partial parts, which are quicker than the authentication mode of the existing block ciphers, which have theoretical safety and which are efficient in the preprocessing and in the used quantity of memory. The message authentication device comprises input means (100) for inputting a message, padding means (101) for padding the message at all times to a constant block length thereby to output it as a padded message, corrected tree hashing means (102) for subjecting the padded message to repeated operations, in which the hash functions of small input/output widths made on the basis of the parts of the block ciphers are arranged for the message, thereby to output the hash value of one block, adjustment-valued encipher means (103) for enciphering the hash value into a tag, and output means (104) for combining the tag and the message thereby to output the combination. |