An easily-reconfigurable unidirectional pipeline for block ciphers

This paper presents an easily-reconfigurable unidirectional pipeline for block ciphers. It detects errors, locates the corresponding faults, and readily reconfigures during normal operation. The modules for decryption (encryption) are used to check the functionality of the modules for encryption (decryption). Tokens, moving along the pipeline with normal data, are used to dynamically assign the modules to operate in the test mode. Bypass links with some extra pipeline stages are employed to achieve robustness to faults. Hardware overhead can be controlled by properly choosing the number of extra stages. Moreover, recovery from errors is achieved with negligible time overhead.