Method and apparatus for authenticating multicast messages

摘要

The last link in an initialization hash chain, calculated by a transmitter based on its anchor value, is distributed as an initialization function value to a receiver in an initialization phase. Subsequently, a multicast message is received and stored by a receiver and an authentication key release message, containing a cryptographic authentication key, is received from the transmitter by the receiver. A cryptographic function value h, calculated by the receiver for the cryptographic authentication key using a prescribed cryptographic function, is compared with the initialization function value to check the validity of the cryptographic authentication key in the authentication key release message. The multicast message is authenticated by the receiver using the cryptographic authentication key which has been recognized as valid.

主权项

1. A method for authenticating a multicast message from among different multicast message types, comprising:
calculating an initialization hash chain in an initialization phase by a transmitter based on an anchor value of the transmitter using an initialization hash function and chain elements of the initialization hash chain provided for initialization of a message protection hash chain; calculating, by the transmitter for each multicast message type, based in each case on an anchor value formed by one of the chain elements of the initialization hash chain, an associated message type hash chain using a respective hash function for the multicast message type; distributing a last chain element of the initialization hash chain as an initialization function value to at least one receiver in the initialization phase; receiving and storing the multicast message by a receiver; receiving, from the transmitter by the receiver, an authentication key release message containing a cryptographic authentication key released by the transmitter for authentication of the multicast message stored by the receiver; calculating, by the receiver, a cryptographic function value for the cryptographic authentication key contained in the authentication key release message using a predetermined cryptographic function; comparing the cryptographic function value of the authentication key calculated by the receiver with the initialization function value to check validity of the cryptographic authentication key contained in the authentication key release message; and authenticating, by the receiver, the multicast message stored in the receiver based on the authentication key that has been recognized as valid.