Cryptography Research, Inc.

Jeremy Cooper

Craig Edward Hampel

Pankaj Rohatgi

Elke De Mulder

Winthrop Wu

Sami James Saab

Systems and methods for determining cryptographic operation masks for improving resistance to external monitoring attacks. An example method may comprise: selecting a first input mask value, a first output mask value, and one or more intermediate mask values; based on the first output mask value and the intermediate mask values, calculating a first transformation output mask value comprising two or more portions, wherein concatenation of all portions of the first transformation output mask value produces the first transformation output mask value, and wherein exclusive disjunction of all portions of the first transformation output mask value is equal to the first output mask value; and performing a first masked transformation based on the first transformation output mask value and the first input mask value.

Determining cryptographic operation masks for improving resistance to external monitoring attacks

Embodiments herein facilitate resisting side channel attacks through various implementations and combinations of implementations. In embodiments, this is accomplished by preventing sensitive data from consecutively following other data through potentially vulnerable resources which otherwise may cause data to leak. Where such vulnerabilities to attacks are known, suspected, or as a proactive precaution, a cleaner can be used to inhibit the sensitive data from passing through the vulnerable areas consecutively and thus inhibit the leakage. Embodiments also envision utilizing certain types of circuits to assist in preventing leakage. By using such circuits one can reduce or even potentially eliminate the requirement for cleaners as mentioned previously.

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Jeremy Cooper