Incorporating a New Pseudorandom Number Generator in AES Algorithm to Improve Its Security Level

Abstract

The implementation of the multiplicative inverses of elemental polynomials under an irreducible polynomial over GF(pn) played an important role in cryptography. In the AES algorithm, the multiplicative inverses under the first irreducible polynomial over GF(28) have been used for the first time in 1999 to design its substitution box. The new PRNG RC4-MI in which the multiplicative inverses under the two irreducible polynomials over GF(73) are being used accepts the AES key as its own key and generates random bytes. Undertaking exclusive OR operation of RC4-MI bytes with AES cipher bytes, one gets a new sequence of cipher bytes thatexhibits randomness quantitatively better than that of the original sequence of AES cipher bytes.