A Note on Strongly Fault-Secure Sequential Circuits
Takashi Nanya, Toshiaki Kawamura · IEEE Transactions on Computers · 1987
It is proved that any sequential circuit with its next-state function d and output function w is strongly fault secure for unidirectional faults in d and w if i) the outputs of w are encoded in an unordered code, and ii) d and w are implemented with inverter-free circuits.