@Darrell O'Donnell reported that this work is moving nicely. The TF is going to stick with the name Trust Registry Protocol and limit the scope of V1 to query operations.
The focus in on finishing the basic ability to query for the status of an issuer, verifier, or another trust registry.
There is discussion about also being able to return the history of an entry for an issuer, verifier, or trust registry because the history can send important signals about trusting that entity.
@Daniel Bachenheimer shared that the history issue is important because a querier could query multiple trust registries to determine the level of trust in a particular entry.
Darrell pointed out that the complexity begins to grow very quickly when additional considerations or requirements are put on the trust registry, so we are trying to keep the scope of V1 very tight.
We also discussed that revocation of a trust registry entry is different than the revocation of credentials issued by that issuer. Keeping the two separate is important.
Sam pointed out that GLEIF has had a similar question come up with the GLEIF ecosystem governance framework (EGF), under which GLEIF authorizes issuers of a credential called a vLEI. That issuer is called a vLEI issuer. If a vLEI issuer is revoked, the vLEI issuer cannot revoke credentials (i.e., the credentials become "zombie" credentials). The solution was for the GLEIF EGF to establish a grace period for vLEI credentials during which the credential is still valid so that the holder of the vLEI credential can find a new vLEI issuer.
@Daniel Bachenheimer noted that the "zombie" credentials may still be trusted in other ecosystems because the issuer revoking from one ecosystem is not necessarily transitive. There are two layers of trust:
Trust in the issuer.
Trust in the credential not being revoked by the issuer.
@Sam Smith pointed out the situation that creates "zombie credentials" is when the reason for revoking trust is that the issuer has lost trust, but the holder has not. This matters within an ecosystem, but may not matter across ecosystems depending on the other ecosystem's policies.
@Drummond Reed noted that the GLEIF EGF work should consider support for the TR Protocol.
He also noted that the GCCN (Global COVID Credentials Network) hosted by LF Public Health is a very eager customer for the TR Protocol.
@Jim StClair noted that the discussions of revocation here is more robust than what is currently begin discussed in the W3C Credentials Community Group (CCG) and their work on an VC HTTP API.
@Sam Smith pointed out that if credentials are not automatically expired in an explicit period of time, then the problem of "zombie credentials" must be solved by the ecosystem. The challenge that the W3C CCG community is facing is that there are different models for privacy-preserving credentials.
@Daniel Bachenheimer pointed out that the way the verifiable data registries work, the issuer can continue to revoke an issued credential. @Sam Smith explained that with ACDC, credentials can be chained, so trust in the credential is chained to higher-level credentials.