This paper presents a novel idea of achieving higher degree of privacy for e-mails using Chebyshev polynomials for 'Pretty Good Privacy' (PGP) (Kenneth and Ballou, 2005). The strength of polynomials lies in their chaotic properties which are potentially suitable for cryptography. A brief discussion on how these polynomials are helpful in providing good security is also presented and the security strengths are evaluated.

Electronic-mail (e-mail) is perhaps the most widely used application on the Internet. An Internet user can send messages to the other Internet users through e-mails. Consequently, the security of e-mail messages has become an extremely important issue. We have three main e-mail security protocols:

E-mail security is a part of cryptography which helps to protect the confidential digital information from the outside world. Nowadays, it is necessary to design complex and efficient algorithms to protect the information due to the rapid growth in processor and other technologies which helps to break cryptographic algorithms up to a certain extent.

In this paper, we introduce the concept of Chebyshev polynomials to conventional PGP—a widely used e-mail security protocol—to enhance the complexity and computational time to break the policy by increasing the decryption time of the cryptographic algorithm. Chebyshev polynomials have important chaotic, periodic and semigroup properties which help in the design of the cryptographic system.

PGP is a combination of both the private key cryptosystem (Atul, 2007, pp. 98-99) (symmetric key cryptosystem) and public key cryptosystem (William, 2006) (asymmetric key cryptosystem) which contains the following phases:

Computer Sciences Journal, Electronic-mail, E-mail Security Protocols, Cryptographic Algorithms, Private Key Cryptosystem, Public Key Cryptosystem, RSA Algorithms, Theoretical Informatics, RSA Data Security, Differential Equations, Chebyshev Polynomials.