Abstract: A block data compression system comprising a Compression unit and a Decompression unit, and an Algorithm for fast block data compression using multi-byte search. Objective of the invention is to develop a block data compression system and algorithm for fast block data compression with multi-byte search for optimal encoding during the learning phase of substitutional methods, allowing length-limited and relative small blocks of input data symbols to be compressed independently, as required by random-access storage or telecommunication devices; and reaching high-performance characteristics by employed accelerating architectures and highly pipelines data-flow principles.