VERIFICATION OF MAC CODE WITHOUT DISCLOSURE THEREOF Russian patent published in 2012 - IPC H04L9/32 

FIELD: information technology.

SUBSTANCE: invention relates to verification of the authenticity of a message (M) transmitted from a transmitting unit (95) to a receiving unit (96) with a cryptographic redundancy corresponding to a message authentication code (MAC) calculated via block encryption. Verification by the receiving unit of cryptographic redundancy accompanying the received message comprises the following steps: a) applying to the cryptographic redundancy (MAC) at least a first decryption using a decryption function (D) corresponding to an encryption function (E), and using a key (K), b) combination (XOR) of the result of that first decryption with a first unit (M'_n) which characterises at least a first portion of data of the received message, c) comparing the result of the combination carried out at step b) with a secret value (IV) stored in memory of the receiving unit, d) and making a decision on recognising the received message as authentic and/or intact if values compared at step c) are identical.

EFFECT: preventing unauthorised MAC disclosure.

15 cl, 10 dwg