Showing papers on "Cryptography published in 1968"
01 Jan 1968
TL;DR: It is the purpose of this treatise to offer a framework within which new cipher systems can be examined, and some of the old ciphers are examined and their weaknesses pointed out.
Abstract: In the unclassified and declassified literature concerning cryptography there is a notable lack of theory unification. Many cryptographic schemes have been proposed and probably used from time to time but few authors have bothered to present their particular theory in such a way that it can be easily contrasted with the others. There is also a sparsity of information con cerning system definition. Just what is meant by a "successful cryptographic system"? It is the purpose of this treatise to offer a framework within which new cipher systems can be examined. First some of the old ciphers are examined and their weaknesses pointed out. With this motivatioh for better cipher systems apparent the problems of a secure crypto system are brought forth followed by some plausible answers. CHAPTER I MATHEMATICAL FUNDAMENTALS Before embarking upon a mathematical formulation of cryptographic processes» it is necessary to be thoroughly familiar with the basic mathematical disciplines which are to be employed in the subsequent chapters» This chapter will present some of the classical concepts from the.fields of number theory, boolean algebra, and information theory. The end of the chapter will be concerned with the very important "uniqueness criterion" which applies to crypto graphic processes. This chapter is not meant to teach the basic definitions and theorems but rather to refresh the reader’s memory. Elements of the Theory of Numbers Natural Numbers. The subset of the positive integers {1,2,3,...} is known as the set of natural numbers (1) .