# WebID and Solid Profile

## Source Type

Standard and ecosystem specification. WebID (W3C CG) for decentralized
identifiers; Solid Protocol for user-controlled data pods and profiles.

## Domain

Decentralized identity-style profile discovery, user-controlled storage, and
WebID-based identification.

## Why This Source Matters

WebID/Solid support user-controlled profiles and decentralized identity-style
profile discovery, relevant to persona, identifier, and data-sovereignty
semantics.

## Key Concepts

- **WebID**: HTTP(S) URI identifying an agent; dereferencing yields profile
  document (RDF).
- **WebID profile document**: RDF description of agent with type, name,
  certificates, and links.
- **Solid Pod**: user-controlled personal data store with access control.
- **Solid Profile**: extended profile in pod with extended attributes and
  preferences.
- **WebID-OIDC**: bridge binding OIDC authentication to WebID URI.
- **Agent type in profile**: self-described person or organization.
- **ACL (WAC / ACP)**: resource-level access control on pod resources.
- **Type Index**: registry of resource types in a pod.
- **Identity provider linkage**: OIDC issuer associated with WebID.

## Relevant Terminology

| Term | Source meaning |
| --- | --- |
| WebID | HTTP URI identifying an agent; profile at same URL. |
| Profile document | RDF at WebID URI describing the agent. |
| Pod | User-controlled storage space. |
| Solid Profile | Profile data stored in pod. |
| Agent | Entity described by WebID (person or org). |
| WebID-OIDC | OIDC flow producing ID token with WebID claim. |
| ACL | Access control on pod resources. |
| Type Index | Discovery of pod resource categories. |
| issuer | OIDC provider linked to WebID authentication. |

## Modeling Assumptions

- **Identifier (WebID URI) is primary**; profile is dereferenceable description.
- **User controls data placement** in pod, not only profile attributes.
- **Agent self-describes** type (person/org) in RDF profile.
- **Authentication can bind OIDC subject to WebID** via WebID-OIDC.
- **Access control is resource-centric** on pod, separate from identity record.
- **No central directory**; discovery via URI dereferencing.
- **Multiple profiles/pods per person** possible across providers.

## Identity-Canon Implications

- **WebID URI** maps to **Identifier** (globally dereferenceable).
- **Profile document** maps to **Profile** with RDF attributes.
- **Pod** maps to user-controlled **Scope** for data storage.
- **Agent in profile** maps to **Actor** (Natural Person or Organization).
- **WebID-OIDC binding** maps to **Synonymity Assertion** / **Identifier
  Binding** between OIDC `sub`+`iss` and WebID URI.
- **ACL** maps to authorization projection on resources in pod Scope.
- Supports S14 (pseudonymous/scoped identity), S02 (multiple profiles), user
  sovereignty goals from ResearchSeed.

## Terminology Conflicts

- **WebID vs. DID**: both decentralized identifiers; different ecosystems and
  resolution models.
- **Profile vs. Account**: Solid profile is data surface; may not include
  login credentials on same system.
- **Agent vs. Actor**: WebID agent is self-described entity; canon Actor is
  broader participation root.
- **Identity vs. WebID**: developers equate WebID with whole identity.
- **ACL vs. Authorization Principal**: pod ACL uses WebID URIs as agents.

## Candidate Canonical Mappings

| WebID/Solid concept | Candidate canonical concept |
| --- | --- |
| WebID URI | Identifier |
| Profile document | Profile |
| Solid Pod | Scope (user-controlled data) |
| Agent (in RDF) | Actor |
| WebID-OIDC binding | Identifier Binding / Synonymity Assertion |
| OIDC iss + sub | Scoped Identifier |
| ACL agent | Authorization Principal (WebID URI) |
| Type Index | Profile/discovery metadata |
| Pod resource | Resource (downstream) |

## Open Questions

- Should WebID URI be a distinct Identifier subtype vs. generic HTTP URI?
- How should WebID-OIDC binding strength compare to OIDC pairwise sub (S14)?
- Does pod Scope warrant a canonical "Data Scope" specialization?
- Should Solid ACL remain purely authorization projection, or inform
  Relationship types for resource sharing?

## References

- Solid Protocol — https://solidproject.org/TR/protocol
- WebID 1.0 (community spec) — https://www.w3.org/2005/Incubator/webid/wiki/Identity_Providers
- WebID-OIDC — https://solid.github.io/webid-oidc-spec/
- Solid Access Control (ACP) — https://solidproject.org/TR/acl-spec