Decrypting the Conversation Key

When the server receives the transmission from the client:

1. The keyserver local to the server looks up the client's public key in the publickey database.

2. The keyserver uses the client's public key and the server's secret key to deduce the common key--the same common key computed by the client. (Only the server and the client can calculate the common key because doing so requires knowing one secret key or the other.)

3. The kernel uses the common key to decrypt the conversation key.

4. The kernel calls the keyserver to decrypt the client's time stamp with the decrypted conversation key.