Carleton University
Technical Report TR-247
June 1994
Randomized Encryption with Insertions and Deletions Based on Probability Distributions
Abstract
We present a new symmetric block encryption technique involving randomized expansions, substitutions, insertions and deletions. The encryption process differs from previous techniques in that the secret key is a set of probability distributions. It is proven that meaningful estimation of these is not possible. The decryption process utilizes a maximum likelihood strategy in the space of potential ciphertext messages to recover a unique plaintext message. As is the case for other wellknown probabilistic encryption methods, the new method docs not provide unconditional security in the information-theoretic sense, but like these, is in some sense reminiscent of Shannon perfect secrecy. Modification of the proposed method to make it suitable for practical use is considered.