I. Introduction
Secure Socket Layer (SSL) is a protocol used to make secure communication between a client and a server [5]. Both the Netscape and Internet Explorer support versions of SSL and the Internet Engineering Task Force (IETF) has approved SSL as a standard. SSL is located between the TCP and HTTP protocols [4]. In this case, HTTP is modified to be HTTP(Secure) abbreviated by HTTPS, which is the standard encrypted communication mechanism on the World Wide Web. The SSL protocol is designed using three interdependent cryptographic functions [5]. Authentication is the first function found in SSL. Its goal is to perform identification and authentication of the parties involved in the communication. Authentication is achieved using public key encryption and a digital certificate issued by a trusted Certificate Authority [8]. There are many public key cryptographic algorithms that could be used to achieve authentication such as RSA, Diffie Hellman and ElGamal. RSA is the most common cryptographic algorithm used to achieve authentication. RSA keys are classified into three categories [1]:
Short Key whose range is less than 900 bits.
Medium key whose range is between 900 and 1250 bits.
Long Key which is greater than 1250 bits.