Transport Layer Security (TLS)

Transport Layer Securities (TLS) are designed to provide security at the transport layer. TLS was derived from a security protocol called Secure Socket Layer (SSL). TLS ensures that no third party may eavesdrop or tampers with any message. 

There are several benefits of TLS: 

• Encryption:
  TLS/SSL can help to secure transmitted data using encryption.
• Interoperability:
  TLS/SSL works with most web browsers, including Microsoft Internet Explorer and on most operating systems and web servers.
• Algorithm flexibility:
  TLS/SSL provides operations for authentication mechanism, encryption algorithms and hashing algorithm that are used during the secure session.
• Ease of Deployment:
  Many applications TLS/SSL temporarily on a windows server 2003 operating systems.
• Ease of Use:
  Because we implement TLS/SSL beneath the application layer, most of its operations are completely invisible to client. 
  

Working of TLS:
The client connect to server (using TCP), the client will be something. The client sends number of specification: 

1. Version of SSL/TLS.
2. which cipher suites, compression method it wants to use. 
   

The server checks what the highest SSL/TLS version is that is supported by them both, picks a cipher suite from one of the clients option (if it supports one) and optionally picks a compression method. After this the basic setup is done, the server provides its certificate. This certificate must be trusted either by the client itself or a party that the client trusts. Having verified the certificate and being certain this server really is who he claims to be (and not a man in the middle), a key is exchanged. This can be a public key, “PreMasterSecret” or simply nothing depending upon cipher suite. 

Both the server and client can now compute the key for symmetric encryption. The handshake is finished and the two hosts can communicate securely. To close a connection by finishing. TCP connection both sides will know the connection was improperly terminated. The connection cannot be compromised by this through, merely interrupted.