Abstract

Cryptography is playing an increasingly important role in the computing and telecommunications industry. The cryptographic schemes currently employed, however, are theoretically breakable given enough time and/or computing resources. Nevertheless, there exists one scheme, the One-Time-Pad, that is theoretically unbreakable given that it satisfies certain requirements. The One-Time-Pad, however, is challenged by serious constraints due to inherent deployment problems. The purpose of this thesis is to outline a pseudo One-Time-Pad-based security system whereby deployment requirements are satisfied while leveraging the inherent strengths of the One-Time-Pad encryption scheme. The One-Time-Pad, also known as the Vernam Cipher, provides unconditional security regardless of the computational resources available. This state of unconditional security is also known as perfect secrecy, and the Vernam Cipher is the only scheme capable of making that claim. There are, however, several strict requirements that must be satisfied in order to guarantee perfect secrecy. The Vernam Cipher requires a truly random source of bits each of which undergoes an exclusive-or Boolean operation with the plaintext message. The problem of distributing a truly random One-Time-Pad to a remote location has severely limited the applicability of the Vernam Cipher for industrial, commercial, and personal use. A pseudo One-Time-Pad-based security system is one wherein a pseudo-random bit sequence is transformed into a cryptographically secure pseudo-random bit sequence, possessing all of the characteristics of the highly desirable truly random bit sequence. This proposed scheme is used in our distributed and secure implementation of the One-Time-Pad encryption scheme.