Symmetric Key Management
Symmetric keys are very good for bulk encryption but are difficult to manage and exchange if only symmetric key cryptography is available. In real-world systems, symmetric keys are typically “use once and throw away.” You create a new random symmetric key for each S/MIME email message or for each connection with TLS. Once you are finished with a particular symmetric session key, you destroy it. In fact, with TLS, a new session key is generated and exchanged periodically since the ...
