This article is from the Secure Sockets Layer Discussion List FAQ, by Shannon Appel SAppel@consensus.com with numerous contributions by others.
Yes. The client and the server each provide part of the random data
used to generate the keys for a connection. (The random portions of
the connection that initiate a session, drawn from both the client
and the server, are used to generate the master secret associated
with that session.) Additionally, each record is protected with a
MAC (Message Authentication Code) that contains a sequence number for