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This the home page for a draft of the ToIP Trust Registry Protocol Specification, a proposed Draft Deliverable of the TSWG developed by the Trust Registry Task Force. The Working Draft of this specification will proceed through three stages:



Status Note

A first generation specification was developed by the first iteration of the TRTF:

This first generation version was published for public review in September 2021. It was not further advanced by the TRTF at that time as there was a consensus that other related specifications needed to be advanced first.

In October 2022, a second generation of the TRTF began working on a second generation specification. Links will be provided here once there is a Working Draft




To comply with the intellectual property rights protections in the charter of the ToIP Foundation (as required by all Joint Development Foundation projects hosted the Linux Foundation), all contributors to this Pre-Draft Deliverable MUST be current members of the ToIP Foundation. The following contributors each certify that they meet this requirement:


Other contributors MUST also add their name and membership affiliation to the Google doc or wiki page version the Working Draft of the spec specification as it proceeds through development.


All other terms in bold will be defined in one or more of the ToIP glossaries in a process being defined by the ToIP Concepts and Terminology Working Group.


The purpose of this specification this specification is to specify a standard interoperable ToIP Layer 3 trust task protocol for standardized interactions with any ToIP-compliant trust registry. For more about ToIP Layer 3 trust tasks, see the ToIP Technology Architecture Specification V1.0.


A core role within ToIP Layer 4 is a trust registry (previously known as a member directory)component of ToIP architecture is a trust registry. This is a network service that enables a governing authority for an ecosystem governance framework (EGF) to specify what a trust community to describe the requirements of its governance framework and specify what governed parties are authorized to perform what actions under the EGF governance framework. For example:

  1. What issuers are authorized to issue what types of verifiable credentials.
  2. What verifiers are authorized to request what types of verifiable presentations.
  3. What other trust other trust registries are trusted by this trust registry.

As with all layers of the ToIP stack, the purpose of a ToIP specification is to enable the technical interoperability necessary to support transitive trust across different trust communities implementing the ToIP stack. In this case, the desired interoperability outcome is a common protocol that works between any number of decentralized trust registries operated by independent governing authorities representing multiple legal and business jurisdictions. One specific example of a trust community with this need is the digital the digital trust ecosystem defined by the the Interoperability Working Group for Good Health Pass (GHP). The GHP Trust Registries Drafting Group produced an extensive set of recommended requirements for a GHP-compliant trust registry.

Trust Registry Protocol v2 Scoping

The v1 trust registry protocol provides answers for three main questions

  1. Is this Issuer Authoritative to issue a particular credential type under a governance framework?
  2. Is a Verifier Authorized to request a presentation under a governance framework?
  3. Does the answering Trust Registry acknowledge another Trust Registry under a governance framework? 

The v2 efforts are exploring the following areas to be included in a new version of the v2 protocol:

  • Approved Wallets - defining the wallet (applications) approved for use in a particular ecosystem.
  • Key Parameters Required (early candidate list):
    • DID Methods - listing the DID Methods supported by a governed ecosystem.
    • Credential Types - List the types of credentials that are in use. This includes:
      • Credential Formats - what formats (W3C JWT/JSON-LD/BBS+/etc/., AnonCreds, etc.)
      • Credential Schema - provides the data structure expected in the credentials.
      • Credential Definitions - provides information about each credential type.
      • Revocation Information - provides information about the approach to revocation, where relevant.
    • Roles - lists, in a simple string array, the formal roles that are active in an ecosystem.
    • EGFURI - URI for the Ecosystem Governance Framework, nominally a DID.
    • Assurance Levels - list the assurance levels defined in the EGF for a governed ecosystem.
    • more to come...
  • Requirements Capture - a loose capture: Trust Registry Protocol v2 - Loose Capture
  • Early input deck: 


This area is for posting and discussing topics relevant to this Task Force.




EU TRAIN Project

TRAIN stands for "TRust mAnagement INfrastructure". It is a subproject run by Fraunhofer-Gesellschaft within the EU eSSIF-Labs Project. This quote is from a recent post to the W3C Credentials Community Group (CCG) mailing list by David Chadwick: