An Efficient Identification Protocol and the Knowledge-of-Exponent Assumption

In this paper, we propose an extremely simple identification protocol and prove its security using the Knowledge-of-Exponent Assumption (KEA). We also discuss the applicability of KEA in various protocol settings as well. Recently, doubts have been raised about applying KEA in some protocols where an adversary has auxiliary inputs. However, we suggest that KEA is applicable in these cases. We present two variants of KEA, Generalized KEA (GKEA) and Auxiliary-Input KEA (AI-KEA), to clarify the proper use of KEA.