WHITE-BOX CRYPTOGRAPHIC SYSTEM WITH INPUT DEPENDENT ENCODINGS

摘要

A white-box cryptographic system is presented wherein at least one of its internal values is represented using an input dependent encoding. The system comprises a network of a plurality of basic blocks arranged for collectively performing a cryptographic operation. An encoder is arranged for encoding output data of a first one of the plurality of basic blocks into an encoder-output according to a selected one of a plurality of encoding schemes, said selection depending on an input-message to the system. A compensator is arranged for recoding intermediate data to compensate for the effect of the encoding according to a selected one of a plurality of recoding schemes. Using variable encodings instead of fixed encodings complicates reverse engineering the white-box cryptographic system.