What is the task of recognizing the truthful source?

Question

Programming

There was a problem about some 10 commanders or some vassals there, and its essence boiled down to the fact that each of them claims something and at first glance it is impossible to find out who is lying, but a methodology is given for mathematical identification of truth and lies. Then the same algorithm was used in some other security systems for authentication.
This task has a characteristic name, remind it, please.

Answer 1

I have not heard of such a task, but as for

Then the same algorithm was used in some other security systems for authentication.

, then very much resembles the Zero-Knowledge Proof