System and method for providing hardware based fast and secure expansion and compression functions

摘要

A system and method for encoding data by providing data expansion and compression functions for arbitrary input and output lengths. The input is partitioned into groups of sequential bits. A subkey is selected from secret key material for each group of the input bits. A tree of XOR gates applies XOR operations between the subkeys to generate the output. The XOR gates are arranged in layers and all the XOR gates within a layer switch at about the same time. A compression function is performed if the input length is greater than or equal to the output length and an expansion function is performed if the input length is less than or equal to the output length. There is no statistical correlation between the input and the output. A nonlinear function can be applied to the output such as an invertible S-Box, non-invertible S-Box, or series of Rotate-Add-XOR operations.