Structural Binary CBC Encryption Mode

A block cipher is a kind of symmetric encryption algorithm that operates on blocks of fixed length, often 64 or 128 bits. It transforms blocks of plaintext into blocks of ciphertext of the same length under the provided secret key. A common characteristic of currently widely used modes of operation such as CBC, CFB and OFB is the sequential procedure, i.e., the encryption/decryption algorithm can not start to process until the previous operation finished, which is considered to be inefficient in multi-processor structures. In this paper, we combine CBC mode of operation and the binary tree data structure to propose a new structural binary CBC encryption mode allowing parallelized computing. A significant property of the proposed mode of operation is independent branch operations. When applied in multi-processor structures, different branch operations can make effective use of CPUs to perform in parallel, which will lead to shorter computing time and greatly improve the overall performance.