SECURITY DEVICES AND PROCESSES FOR PROTECTING AND IDENTIFYING MESSAGES

摘要

The present invention relates to a security device (3) and process for protecting messages (MSG) despatched to a receiver (2) comprising means of control of identification (21) by a modifiable current identification key (K'i). It also relates to a corresponding device (4) and a corresponding process for identifying messages.The security device comprises a unit for control of enciphering (11) of at least a part of each of these messages by means of a modifiable current enciphering key (Ki), in such a way as to produce a signature added to the message. It also comprises a unit (12) for changing the current enciphering key, selecting this key from a predetermined set (16) of available enciphering keys (K1 Kn), as well as a unit (13) for registering a key identifier (KeyID) in this message. The key identifier enables the receiver to select the current identification key from a predetermined set (26) of available identification keys (K'1 K'n) in such a way that the current enciphering and identification keys correspond to each other. Moreover, the messages are service announcement messages.Applications to message authentication.