METHOD AND APPARATUS FOR ENCODING A SIGNAL USING INCOMPLETE UNBALANCED FEISTEL NETWORKS

摘要

A cryptographic process which receives input and which performs cryptographic operations on logically contiguous blocks of intermediate text, the intermediate text comprising Z bits, to generate output, the cryptographic process comprising an unbalanced source-heavy incomplete Feistel network which comprises: a round function: which is invoked at least twice; and each invocation of which invokes at least a non-linear sub-round function and a sub-round function, and in which: the non-linear sub-round function generates output that updates a block of the intermediate text which is at a first index position I1 of the intermediate text; the sub-round function generates output that updates a block of the intermediate text which is at a second index position I2 of the intermediate text which is different from the first index position I1.