Elliptic curve exponentiation apparatus that can counter differential fault attack, and information security apparatus

摘要

Provided is an elliptic curve exponentiation apparatus that can counter the DFA when an elliptic curve exponentiation technique is used. A computation result verification unit 127 receives, as a computation result, an exponentiation-result-point (X, Y) from an elliptic curve computation unit 124. The computation result verification unit 127 computes X³+axX+b, and computes Y², and outputs the received exponentiation-result-point when judging that Y²=X³+axX+b, and does not output the received exponentiation-result-point when not judging that Y²=X³+axX+b.