An issuer registry, a type of trust registry which can be used in W3C Verifiable Credential Ecosystems, is a dataset which contains a list of “known issuers” and their unique identifiers like URLs (uniform resource locators) or DIDs (decentralized identifiers). In the case of education or training credentials (sometimes referred to as Learning and Employment Records, or LERs) issued as VCs (W3C Verifiable Credentials), these issuers could include universities, employers, or professional training programs which issue diplomas, certificates, or badges. The issuer registry can be maintained and governed by an accreditation body, a government, a nonprofit, or another kind of entity. The main purpose of the issuer registry is to provide an additional layer of trust in the credential through a mechanism which checks and verifies the identity of the issuer."