IPSEC

The IP security (IPSec) is an Internet Engineering Task Force (IETF) standard suite of protocols between two communication points across the IP network that provide data authentication, integrity, and confidentiality.
 

It also defines the encrypted, decrypted and authenticated packets. The protocols needed for secure key exchange and key management are defined in it.

Uses of IP Security –

IPsec can be used to do the following things:

• To encrypt application layer data.
• To provide security for routers sending routing data across the public internet.
• To authenticate that the data originates from a known sender.
• To protect network data.

• Security Parameter Index(SPI):
  This parameter is used by the Security Association. It is used to give a unique number to the connection build between Client and Server.
• Sequence Number:
  Unique Sequence numbers are allotted to every packet so that at the receiver side packets can be arranged properly.
• Payload Data:
  Payload data means the actual data or the actual message. The Payload data is in encrypted format to achieve confidentiality.
• Padding:
  Extra bits or space added to the original message in order to ensure confidentiality. Padding length is the size of the added bits or space in the original message.
• Next Header:
  Next header means the next payload or next actual data.
• Authentication Data
  This field is optional.