A File Encryption Algorithm Based on Dynamic Block Out of order Matrix Mapping In order to solve the security of content transfer during file transfer and fast encryption of large files. This paper proposes a method to quickly encrypt large files and protect the contents of file information, also prevent files from being intercepted and decrypted before use. The algorithm of file encryption based on dynamic block out of order matrix mapping. First, dynamically block the files according to a certain ratio, extract the raw data and key information of each block, then store the out of order data into a twodimensional table of matrix after calculation and processing. Second, use Base64 encoding on this matrix mapping table. Then the matrix mapping table is to be a unique decryption key of this file. After that, the data in the spare block of the file is filled with the MD5 data, the MD5 data is generated by UUID and block with the same size as the number of dynamic block. The new encrypted file whose length is equal to the original file. Because it is dynamic block and random extracted data, so it is fast and efficient. The experimental results and security analysis show that the algorithm has a good encryption structure and high security, which can effectively resist various attack behaviors. Most of the files that with different types can be used, and the speed to encrypt and decrypt large files is greatly improved compared with the traditional encryption and decryption methods, the speed and efficiency far exceed the traditional file encryption and decryption algorithms, such as AES, DES, 3DES and so on.

The fast image encryption algorithm based on lifting scheme and chaos Abstract   Image encryption technology is one of the most important means of image information security. Most image encryption algorithms are based on a permutationxe2x88x92diffusion structure. However, some image cryptosystems based on this structure have been proved to be insecure. Thus, a new image encryption structure based on a lifting scheme is proposed in this study. In the proposed algorithm, the plain image is decomposed into lowfrequency approximate components and highfrequency detailed components. Pseudorandom sequences generated by chaos are employed to sequentially disturb the two sets of components. Then a lifting scheme is used for image encryption. Compared to the currently popular permutationxe2x88x92diffusion structure, the proposed image cryptography requires fewer pseudorandom numbers, and it has a faster encryption speed and higher security. Simulations, performance analysis, and comparison tests show that the proposed method has the advantages of large key space, fast encryption and decryption speeds, strong system sensitivity, and excellent encryption security. The algorithm can be used in applications such as encryption of medical and cloud images.