US Patent 7334178 Randomized self-checking test system

Methods and apparatus are provided for verifying and validating operation of a design under test (DUT). Input data sequences having information used to check expected outputs are provided to a DUT. The input data sequences include checking headers and data. The checking headers and data are randomized using encryption to verify and validate operation of the DUT on a variety of bit sequences. Different keys are used to allow further scrambling.