• The internet and web has become widely popular today. However, it is vulnerable to serious attacks.
• For this purpose, various security approaches are possible. These approaches are mainly dependent on which network layer they operate on (Remember the network layers of CN!!).
• The SSL (Secure Socket Layer) is a whole new layer of protocol which operates above the Internet TCP protocol and below high-level application protocols
• There are different protocols which are associated with SSL which are used in the management of SSL exchanges.

One among those is SSL handshake protocol.

• It is one the most complex protocols of SSL.
• It allows client and server to:
  • Authenticate each other
  • To negotiate encryption & MAC algorithm.
  • To negotiate cryptographic keys to be used.
• The Handshake Protocol is used before any application data is transmitted.
• The handshake protocol is made up of a series of messages exchanged between both parties (server & client) which is of the format

• These messages are communicated as a series of messages in phases (4 phases) (Diagram shown below…)

  a) Establish security capabilities : this phase is used by the client to initiate a logical connection and to establish the security capabilities that will be associated with it

  b) Server Authentication and Key Exchange: The server begins this phase by sending its certificate if it needs to be authenticated.

  c) Client Authentication and Key Exchange: the client should verify that the server provided a valid certificate if required and check that the

  d) Finish: this phase completes the setting up of a secure connection.