[Preprint] A Verifier-Centric Conceptual Model for Digital Credential Ecosystems

(Cross-posted to public-vc-wg, public-did-wg, and public-credentials —
apologies for the duplicates.)

Dear all,

Ryosuke and I have posted a preprint that may be of interest to some of
the discussions running across CCG, VCWG, and DIDWG:

  A Verifier-Centric Conceptual Model for Digital Credential Ecosystems
  Decomposing Verification into Establishment, Acceptance, and
  Materials Acquisition

  Shigeya Suzuki and Ryosuke Abe
  https://arxiv.org/abs/2607.10747

The paper starts from a practical question: why do stacks that share a
data model still fail to interoperate? Our position is that
interoperability is not format compatibility — it is the condition that a
verifier can obtain the materials it needs and reach an acceptance
decision under stated assumptions. To make that discussable, we decompose
credential processing into three layers (signature verification, semantic
interpretation, validation) and model the supply of verification materials
as two orthogonal planes (Constitution and Logistics), with a formalization
of trust running across all five functions.

The abstract follows. Comments, corrections, and disagreement are all
very welcome — on-list or off. 

Note: I will be at IETF 126 coming next week.

--- Abstract ---

Digital credential ecosystems increasingly combine multiple standards.
Because implementations have evolved independently across jurisdictions
and application domains, systems described under the common label "digital
credential" often remain mutually non-interoperable. Conventional
element-by-element comparisons of identifiers, data models, credential
formats, protocols, and signature algorithms do not explain why
interoperability fails even when stacks share a data model, nor do they
identify what a verifier must obtain, and what it must trust, before
accepting a credential. We present a verifier-centric conceptual model
built on two decompositions. The first separates credential processing
into signature verification (L1), semantic interpretation (L2), and
validation (L3), and models the supporting materials through two
orthogonal planes: Constitution, which captures ecosystem-level
arrangements and trust declarations, and Logistics, which captures how
verification materials are stored and delivered; the Shinken framework
makes trust assumptions explicit across all five functions. The second
characterizes where each function may be placed along three dimensions
(placement, timing, and disclosure). From the condition of being
verifiable, the model derives seven consequences, distinguished as
definitional corollaries, operational implications, and design trade-offs.
Applying the model to four learner-credential stacks and to existing
ecosystems including authentication federations, we show that it explains
interoperability failures, verifier-side burden, offline verifiability,
privacy implications, and terminological ambiguities that element-wise
comparison leaves unresolved.

--- End of abstract ---

Two disclosures. This is a preprint, submitted to IEEE Access; it
has not been peer-reviewed yet. And we are involved in the design of Originator
Profile, which appears in the cross-ecosystem comparison; this is stated in
the paper as well.

Regards,

Shigeya Suzuki, Ph.D
Project Professor, Keio University Global Research Institute
Char of Technology Development, Originator Profile CIP

Received on Tuesday, 14 July 2026 23:14:21 UTC