IPsec Protocol

IPsec protocol is a standard that is used in VPNs to secure the IP networks.IPsec protocol also protects and authenticates the IP packets that are sent from the source to the destination. The main functions of the IPsec protocol are as follows.

• Authentication using Internet Key Exchange (IKE).
• Integrity using hashing.
• Confidentiality using encryption.
• Secure key exchange using the Diffie-Helman algorithm. 

The IPsec framework is very flexible so that the users can integrate it to new security technologies.To learn about how this framework can be aligned to different security functions and standards lets get to know about the IPsec framework.

IPsec Framework

The IPSec framework consists of 5 levels. They are IPsec protocol, confidentiality, integrity, authentication and Diffie-Helman.

IPsec protocol 

This consists of Authentication Header (AH) and Encapsulation security protocol (ESP) , hear either one or both can be used.In this layer the AH can be used to authenticate the Layer 3 packets and the ESP can be used to encrypt layer 3 packets.

Confidentiality layer 

This secures the confidentiality of the layer 3 packets. This layer consists of encryption standers such as Data encryption standards (DES), Triple DES (3DES), Advances encryption standards(AES), or the SEAL encryption standard.

Integrity Layer 

In this layer it makes sure that the data that is sent across and unchanged at using the hashing algorithm . This uses hashing algorithms such as the message-digest 5 (MD5) or Secure Hash algorithm (SHA)

Authentication Layer

This uses the Internet Key Exchange (IKE) to authenticate users as well as devices . For this it uses various methods such as user name passwords , bio-metrics, pre-shared keys (PSK), (RSA) Algorithm, and onetime passwords.

Diffie-Helman

Diffie-Helman is used in the framework to provide a public key exchange method among the two pears and to create a secret key. For this you can select from DH14,15,19,20,21.

IPsec Implementation

When dealing with the IPsec protocol you must be aware of the IPsec Security Association as this is considered as a fundamental concept of IPsec.  IPsec Security Association is a relationship among the two entities that communicates with each other. Hear the entities must describe how they will be using the security services to communicate securely. The pears must have the same SA to negotiate the Key to exchange it with each other. Below is an illustration of how the SA can be used.