MANAGING SECURE COMMUNICATIONS WITH MULTILEVEL SECURITY AND RESTRICTED CHARACTER SET TRANSLATION

Abstract

Naval message traffic is transmitted with restricted character set, the files of which are optionally compressed. Often in this type of transmission, both character set translation and data compression can be used as add-on data encryption. In supporting the multilevel security management of access control in communication, this paper presents a possible implementation of master keys. The underlying basis of this key management scheme allows a set of keys to be maintained in either a floating or connected fashion, thus making the system tolerant to expansion. In doing this, it is discovered that a direct implementation for master keys is not possible as modulo arithmetic is required whereby only the arithmetic operations of addition and multiplication follow the commutative property-not division, where the results of modulo division are irreversible. As a solution to this problem, a recursive procedure of modulo exponentiation is employed via software which utilizes indexes. Along with this research, an algorithm has been implemented with restricted character set translation scheme and incorporated into a data compression program for military applications. The restricted character set translation algorithms investigated for the U.S. Navy are discussed in this paper. The application of character set translation will defer hardware changes, and the software implementation alleviates the need for expensive hardware.