Abstract: A secure microprocessor is designed using quad-coded logic which is similar to dual-rail encoded asynchronous logic except that the ‘11’ state propagates an alarm. The alarm signal obliterates secure data in its path. Quad-coded logic provides resilience to power glitches and single-transistor or single-wire failures. The already low data dependency of the power consumption makes power analysis attacks difficult, and they are made even more difficult by inserting random delays in data and control paths, and by a set-random-carry instruction which enables software to make a non-deterministic choice between equivalent instruction sequences. These features are particularly easy to implement well in quad-coded logic.

Abstract: A secure microprocessor is designed using quad-coded logic which is similar to dual-rail encoded asynchronous logic except that the ‘11’ state propagates an alarm. The alarm signal obliterates secure data in its path. Quad-coded logic provides resilience to power glitches and single-transistor or single-wire failures. The already low data dependency of the power consumption makes power analysis attacks difficult, and they are made even more difficult by inserting random delays in data and control paths, and by a set-random-carry instruction which enables software to make a non-deterministic choice between equivalent instruction sequences. These features are particularly easy to implement well in quad-coded logic.