This part of ISO/IEC 9798 specifies entity authentication mechanisms using zero-knowledge techniques:. mechanisms based on identities and providing unilateral authentication;. mechanisms based on integer factorization and providing unilateral authentication;. mechanisms based on discrete logarithms with respect to numbers that are either prime or composite,and providing unilateral authentication;. mechanisms based on asymmetric encryption systems and providing either unilateral authentication, ormutual authentication;. mechanisms based on discrete logarithms on elliptic curves and providing unilateral authentication.These mechanisms are constructed using th