SSL - Secure Sockets Layer

As a part of study, wanted to dig into one protocol which uses Certificates for hanshake. Selected SSL. SSL works above transport layer. Protocols like HTTPS uses HTTP over SSL for secure communications. VPNs like OpenVPN also uses SSL as the underlying protocol.

SSL uses
stage 1. Assymetric encrption for intial handshake - authentication and privacy
stage 2. and later moves to faster symmetric encryption for further communication using the Master Key generated during the first stage.

Brief Idea on how the protocol works is:
1. Client sends HELLO to Server ( and details like Cipher suites, session data etc)
2. Server sends back ACK ( Session specific data and Cipher Suites and SERVER CERTIFICATE)

3. Now Client verifies the Server Certificate... Only if it is ok the client proceeds further.

4. Now client sends data encrypted by Server's PUBLIC Key. Client sends the pre-master secret key to the Server.

5. Now the mystery part ( Its still a mystery to me). Client and Server uses the pre-master secret to generate a master secret. Using Master Secret Client and Server generates Session Keys...

6. Now Client sends an encrypted message to Server saying that hanshake is completed. Server also sends a similar message to the client..

7. Now on all data between client and server is encrypted by the session keys..

In the default mode, only Server is authenticated. But Client side certification can also be given. In this case, client will also send its certificate in the step 4 mentioned and Server verifies it.

Assymetric algorithms used are : RSA, Diffie Hellman
Symmetric Ciphers: Triple DES, RC4, RC2, DES