Abstract: The current network scenario demands secure and fast communication of information. This requires both compression and encryption. Arithmetic coding provides compression as well as data security. In fixed model arithmetic coding security is improved by assigning symbol frequencies arbitrarily rather than matching the frequency of occurrence in the source input and by means of random symbol ordering. In this paper security is enhanced by randomly assigning probabilities to frequency of occurrence using pseudo random numbers and finding the product between frequency of occurrence of the character and randomly selected probabilities and by not altering the frequency of occurrence and symbol ordering. The associated frequencies of the symbols do not match with the actual frequencies of the symbols.
Keywords: Data security, Arithmetic coding, Random probability, seed value generation