A Huffman Code Based Crypto-System

A Compression Cryptosystem is a single coding process, the output of which is both reduced in space and secure against unauthorized decoding. Considering Huffman coding, this pa-per proposes to apply repeatedly minor changes to the compression model, with negligible deterioration of its optimality. The cumulative impact of a large number of such changes leads to completely different ciphertexts, which can be decoded only if a given secret key is known. The security of the system is based on the NP-completeness of a problem related to breaking the code. Several variants are suggested, and their results are tested in various settings, including for security against chosen plaintext attacks.