Message Sequence Integrity <A NAME=x400msi> </A>

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Message Sequence Integrity  

Message sequence integrity provides proof that the ordering of a sequence of messages sent from an originator to a recipient has been preserved. This service counters message sequencing threats, such as the replaying and re-ordering of messages. It is provided on a per-recipient basis using symmetric or asymmetric encryption techniques.

To provide the service, the message originator generates a sequence number, which identifies the position of the message in the sequence. This number is transferred in the message token's signed-data, or if the secrecy of the number is required, in the token's encrypted-data. Each originator/recipient pair using this service maintains a distinct pair of sequence numbers. One drawback with the message sequence integrity service is that it requires all users to maintain pairwise sequence numbers with (potentially) all other users.

John Barkley
Fri Oct 7 16:17:21 EDT 1994