Providing assurance of the identity of an entity interacting with a system is:

1. Two kinds of authentication are distinguished. 2. One is about who is on the other end. 3. Identity authentication provides assurance of the identity of an entity interacting with a system. 4. So the answer is identity authentication. _Source: NIST SP 800-175B Rev. 1, 'Guideline for Using Cryptographic Standards in the Federal Government'_