| 摘要 |
Method for authenticating a multicast message having the following steps: An initialization hash chain is calculated (S1) by a transmitter on the basis of an anchor value for the transmitter, and the last chain link in the initialization hash chain is distributed as an initialization function value to at least one receiver in an initialization phase (IP), a multicast message (MC-N) is received (S2) by a receiver, which stores the received multicast message (MC-N), an authentication key release message (KRM) is received (S3) from the transmitter by the receiver, wherein the authentication key release message (KRM) contains a cryptographic authentication key (K) released by the transmitter for the purpose of authenticating the stored multicast message (MC-N), a cryptographic function value h (K) is calculated (S4) for the cryptographic authentication key (K) contained in the authentication key release message (KRM) by the receiver using a prescribed cryptographic function (H), the cryptographic function value h (K) - calculated by the receiver - of the authentication key (K) is compared (S5) with the initialization function value (hn) distributed to receivers by the transmitter in advance in the initialization phase (IP) for the purpose of checking the validity of the cryptographic authentication key (K) contained in the authentication key release message (KRM); and the multicast message (MC-N) which comes from the transmitter and which is stored in the receiver is authenticated (S6) by the receiver using the cryptographic authentication key (K) which has been recognized as valid. |
