"Network Security 0-100" Key Distribution Protocol

1. Key distribution protocol

1.1 Basic key distribution

A and B want to communicate, and A sends A and B to S. The server returns, T is the timestamp.

A decrypts the first block through K_(AS, obtains K_[AB, and sends the second block message and the communication message M encrypted with K_(AB to B. B decrypts with his own K_(BS, obtains K_[AB, and sends The message is decrypted with K_(AB.

But A can use the replay attack to gain the trust of the server, so the timestamp should be added.

 1.2 Needham-Schroeder agreement

 1.3 Kerberos protocol