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Abstract : |
We present the eXtended Ciphertext Block Chaining (XCBC) schemes or modes of encryption that can detect encrypted-message forgeries with high probability even when used with typical noncryptographic Manipulation Detection Code (MDC) functions (e.g., bitwise exclusive-or and cyclic redundancy code (CRC) functions). These modes detect encrypted-message forgeries at low cost in performance, power, and implementation, and preserve both message secrecy and integrity in a single pass over the message data. Their performance and security scale directly with those of the underlying block cipher function. We also present the XECB message authentication modes. These modes have all the operational properties of the XOR-MAC modes (e.g., fully parallel and pipelined operation, incremental updates, and out-of-order veri cation), and have better performance. They are intended for use either stand-alone or with encryption modes that have similar properties (e.g., counter-based XOR encryption). However, the XECB-MAC modes have higher upper bounds on the probability of adversary's success in producing a forgery than the XOR-MAC modes., |
