Authentication

Authentication is the technique by which a process verifies that its communication partner is who it is supposed to be and not an imposter.

Authentication is the process of validating the identity of someone or something. It uses information provided to the authenticator to determine whether someone or something is in fact who are what it is declare to be. For example in public and private computer networks the process of authentication commonly involve someone usually the user using a password provided by the system administrator to login.

The user’s possession of a password is meant to guarantee that the user is authentic. It means that at some previous time, the user requested to the system administrator and the administrator assigned and or registered a self selected password. The user presents this password to the login to prove that he or she knows something no one else could know.

Authentication Methods

Different authentication methods are user based on different authentication algorithms. These authentication methods can be combined or used separately, depending on the level of functionality and security needed. These authentication methods are:

1. Password authentication

The password authentication methods are the oldest and easiest to implement. They are usually set up by default in many systems. Password authentication includes reusable passwords one time passwords challenge response passwords and combined approach passwords.

(a) Reusable Passwords

Two types of reusable password authentication are user and client authentication.

User authentication is the most commonly used type of authentication. It is always initiated by the user, who sends a request to the server for authentication and authorization for use of specified system resources. On this request the server provides a user name and password to the user. On submission of this, the server checks for a match in its database. Based on the match authorization is granted.

Client authentication is a versatile authentication method. Unlike user authentication in which a connection is being authenticated here you authenticate a machine or an IP. Client authentication is not transparent which means that the connection has to be directed to the firewall so that it can ask for the specific authentication are that any service can be authenticated and that authentication can last for a specific period of time or number of sessions. Once a user achieves client authentication traffic can flow freely with little intervention.

(b) One time passwords

One time password authentication is also known as session authentication. Unlike reusable passwords tat can be used over extended periods of time, one time passwords are used once and disposed off. They are randomly generated using powerful random number generators. This reduces the chances of their being guessed.

(c) Combined response passwords

Combined approach authentication uses several combined authentication scheme for enhanced security. One of the most secure authentication methods is to use a random challenge response exchange using digital signatures.

2. Public key authentication

The invention of public key cryptography solved the problem of secure key agreement in conventional secret key cryptosystems. Public key systems are routinely used by authentication systems to enhance system security. The centralized authentication server commonly known as access control server in in-charge of authentication using public key systems. When a user tries to access an ACS it looks up the user’s public key and uses it to send a challenge to the user. If the user then signs the response using his private key, the user is authenticated as right person.