A Security evaluation of certain stream ciphers which involve randomness and coding

Following some of the recently reported results, an approach for design of stream ciphers has been considered which is based on joint employment of pseudorandomness, randomness and dedicated wire-tap channel and error correction coding. The wire-tap channel coding controlled by the randomness, provides that an attacker faces not only the traditional problems of cryptanalysis but also the problem of decoding without the secret key which appears as complex as the exhaustive search over the possible secret keys. Security evaluation has been performed based on the algebraic representation of the proposed stream cipher. The given security evaluation has addressed hardness of the algebraic recovering of the secret key in the CPA scenario. It is shown that the secret key recovery is as hard as the LPN∊ problem where ∊ = 1−(1−2)^(m−ℓ)/2/2 and m, ℓ and p are the stream cipher parameters.