An Asymmetric Text Encryption Method Based On Lossless Compression And Chaos Theory

With the development of the information age,a large quantity of PC owner's personal data spread on the network and some criminals attack and steal these private information illegally to get themselves on, causing PC owner tost varying degrees of loss both spiritually and materially. In order to make users' private information on the network spread more safely and minimize the owner's losses to a certain degree, it is the best way to encrypt the personal information.On the basis of fully understanding the traditional encrypted mechanism,it has been found that the traditional encrypted mechanism has more or less defects by the author of the literature. In the existing encryption algorithm, the RSA encryption algorithm is a public-key method which is safe and it is difficult to provide the key for RSA. And it is ok for chaos theory applying in the field of information security because chaos theory and cryptography are closely connected. Thus, in order to ensure that the encryption algorithm not only has the advantages of high safety but efficient,this paper proposes an asymmetric text encryption method based on lossless compression and chaos theory.In this paper, the one-dimensional logistic map is used as a chaotic system to generate chaotic sequence firstly. And next, in order to improve the randomness of the chaotic sequence to a certain extent, chaotic sequence is scrambling by Joseph's ring.Then, we make the chaotic sequence combine with plaintext sequence and execute a series of operations to disturbing the plaintext. Next, the RSA algorithm and the cipher-text have been further operated to produce the final cipher-text. In order to improve the efficiency of the encryption algorithm in the article, a IRLE lossless compression algorithm is proposed. The IRLE lossless compression algorithm is an improved algorithm for the RLE algorithm to improve the compression rate in the case of a large number of non-repetitive characters. In order to save storage space and improve the compression rate, we first use the RLE algorithm to compress the text and then take compressed character's ASCII code to iterative calculate and finally we generate a IRLE number in the IRLE lossless compression algorithm. Finally, the IRLE lossless compression algorithm is applied to the encryption algorithm mentioned earlier in the article.Through repeated tests, the IRLE lossless compression algorithm is proposed that can compress and decompress correctly, further more can improve the compression ratio contrast with the RLE algorithm and its time complexity has reached to O(n) in this paper. The IRLE lossless compression algorithm is applied to the asymmetric text encryption algorithm based on chaos theory proposed in this paper, and then the whole encryption algorithm is tested from three aspects: function, performance and security.The results of function and performance analysis show that the encryption algorithm can correctly encrypt and decrypt and its time complexity has reached to O(n). The experimental data of security analysis show that the chaotic sequence in the process of encryption algorithm is random, chosen plain text attack is very difficult and the probability of brute force to obtain the correct key is very small. In all, the three aspects guarantee the encryption algorithm safety together.