Randomized pseudo-probabilistic encryption algorithms

Abstract

The aim of the paper is providing resistance of the deniable encryption protocols to coercive attacks at which coercer has possibility to cause repeated encryption of the same input messages and/or to estimate the duration of the decryption procedure performed for disclosing the secret message. It is used the method of randomizing the encryption process and the same decryption algorithm is specified to disclose both the secret and the fake messages. There are introduced randomized pseudo-probabilistic block algorithms for deniable encryption which are implemented as probabilistic simultaneous encryption of the fake and secret message. The proposed algorithms include encryption of the secret message block and the fake message block followed by a randomized mapping the pair of intermediate ciphertext blocks into a single block of the output ciphertext. The mapping procedure represents solving the system of three linear congruencies.