On Hillclimbing Algorithm Of Cryptographic Boolean Fumctions

Cryptography is the core of information security. The design of Boolean function is one of the most significant problems in cryptography. In this thesis, both the cryptography development and the Boolean function design studying status are introduced. The algebra knowledge of cryptology is introduced and the security measure indexes on Boolean functions are analyzed. The main part is researching the theory and process of hill-climbing algorithm which is an intelligent algorithm of Boolean function. The improvement of the algorithm is given and realized, the result analysis is given too.The main results are as follows:1. Under the comprehension of Boolean function and its security measure indexes; there is a deep research of the algorithm theory and process.2. Two improvement train of thought is posted and the proof is given. Furthermore, the Ruby language which is very convenient was used to choose a good combination mode. At last, the new algorithm DIMHC is given. Then, using the algorithm procedure, several Boolean functions are designed. By analysis of the design result, the algorithm is certain to have a better effect on get high nonlinearity Boolean function.4. The experience of develop Boolean function by Ruby is given and the source code is given in appendix.