Research On The "One-Group-One-Cipher" Cryptograph Of Block-Cipher Based On Chaotic

Nowadays many practical cryptosystems are computational security, whereas big challenges are emerging with the improvement of computing capacity and cryptanalysis technology, and especially the rapid development of quanta and DNA computation. The one-time pad is regarded as the only unconditionally secure system among existing traditional cryptosystems, which is however hard to implement due to the difficulty of key management.Studied on block and chaotic ciphers, the existing combined cipher of block and stream was analyzed in this thesis, and then a better and safer algorithm of"one-group- one-cipher"was presented.The main contents in this thesis are as follows.(1) The"one-group-one-cipher"algorithm used the sequence from chaotic mapping as sub-key for block cipher was presented to solve the problem of weak keys existing in currently combined cipher algorithms.(2) The initialization of hyper-chaos generalized Hénon mapping and the method of abstracted digital key sequence were studied. The randomness of abstracted key sequence was validated in aspects of invariant distribution, Shannon entropy, local randomness and linear complexity.(3) The"one-group-one-cipher"algorithm was designed and implemented based on hyper-chaos generalized Hénon mapping and IDEA algorithms, and its security was analyzed theoretically and validated practically, and showed that the algorithm can withstand various cryptanalysis include Brute force attack and statistical analysis.In this study, the advantages of chaotic system are applied to block cipher. The algorithm not only has theoretical security of block ciphers, but also has randomness and unpredictable of chaotic cipher. The disadvantages of key's reuse of block ciphers are avoided, and the practicality and feasibility of chaos ciphers are improved.