Web of trust

 Web of trust  (sometimes PGP Web of Trust ) is a highly technical method of sharing identities that you trust or distrust, with your friends or strangers, in a decentralized way without requiring a centralized authority.

Features:
 * a ranking can be assigned to convey different levels of trust or distrust.

Longer description:
 * https://en.wikipedia.org/wiki/Web_of_trust

Technical descriptions:
 * PGP Web of Trust - Core Concepts
 * 2015 WebOfTrustInfo/rwot1-sf/ - /topics-and-advance-readings/PGP Paradigm

Confused With

 * https://www.weboftrust.info/ — is about the Rebooting Web of Trust series of conferences, not a description of any technology.