Research On Improvement Of RC4 Stream Cipher Algorithm

The RC4 stream cipher algorithm is widely used in the fields of network security transmission,streaming media encryption,electronic information encryption and so on.With the rapid development of the Internet era,the information network provides more convenient services and the security problems are quietly increasing,the RC4 algorithm is seriously threatened and faces severe challenges.Aiming at the problem that the key stream sequence of RC4 algorithm is not high random and vulnerable to fault introduction attack,distinguishing attack,state guessing attack and Bar Mitzvah attack,an improved RC4 algorithm based on elliptic curve and random number generator is proposed.Firstly,the seed key Key is generated by using the random bit generator and the random large prime number in the key schedule algorithm to ensure the randomness and security of the initial state of the S-box.Secondly,the elliptic curve is used to generate the secret integer in the pseudo random generation algorithm,after each output the elements in the S-box are re-assigned,and the generated key stream sequence is determined by three mathematical difficulty problems,which increases the difficulty of cracking the key stream sequence and enhances the security of the improved RC4 algorithm.The feasibility and randomness of the improved RC4 algorithm are tested and analyzed.The NIST randomness test tool is used to detect the frequency test,runs test,overlapping template matching test and other index of the key stream sequence.The experimental results show that the improved algorithm are higher than the RC4 algorithm by 0.13893,0.13081,0.03984 in the original three indexes.Therefore,the key stream randomness of the improved algorithm is higher than the original algorithm,which effectively prevent the generation of invariant weak keys and can resist the Bar Mitzvah attack;the key stream sequence is evenly distributed,without deviation,and it can effectively resist the distinguishing attack.The secret integer generated by the elliptic curve is difficult to guess.The internal state of the S-box is not known,and it can resist the fault-introduction attack.The secret integer guessing based on the elliptic curve is difficult to guess,and the internal state of the S-box cannot be known,which can resist the fault introduction attack.Theoretical and experimental results show that the improved RC4 algorithm is more random and safe than the RC4 algorithm.The thesis has 15 pictures,1 tables,and 55 references.