# Description
Introduces a pluggable user-identity provider model covering all OPC UA
Part 6 §6.5 mechanisms (Anonymous, UserName, X509, IssuedToken/JWT) on
both client and server, with full
`Microsoft.Extensions.DependencyInjection` integration, plus the Part 12
§9 `AuthorizationService` two-phase token-request flow **including
refresh-token rotation**, the Part 12 §8 KeyCredential Push model, and a
clean provider model for OPC 10000-12 §7.2 `ApplicationSelfAdmin`. The
work is split across phase-by-phase commits so it can be reviewed
independently; nothing here changes wire-level behaviour or forces
existing applications to migrate.
### Documentation
All under `Docs/`:
- `IdentityProviders.md` — full developer guide: three-layer model,
recipes, configuration reference, "what gets auto-wired" matrix, JWS
algorithm table, identity-augmenters section, **"Implementing your own
provider"** how-to subsections for Entra / OIDC / Windows / AspNetCore
(sibling files merged in per review feedback).
- `DependencyInjection.md` — `Identity` sections with `appsettings.json`
examples, identity-extension matrix, `WithAuthorizationService` +
`WithKeyCredentialPush` + `AddIdentityAugmenter` extensions documented.
- `RoleBasedUserManagement.md` — claim-criteria callout describing
`IIdentityClaims` probe surface.
- `AuthorizationService.md` — Architecture diagram +
`IAccessTokenProvider` conceptual narrative restored from master; modern
`StartRequestToken` / `FinishRequestToken` flow leads; refresh-token
recipe added.
- `KeyCredentialService.md` — Push model + Pull vs Push vs Bridge
decision matrix + Hybrid (Push + Pull) section; explicit experimental
warning for the bridge.
- `GDS.md` — KeyCredential Push, `StartRequestToken`,
`GdsApplicationSelfAdminProvider`, **shipped Refresh-token support with
rotation policy and audit semantics** all documented.
- `MigrationGuide.md` — User Identity Providers section listing
`[Obsolete]` markers + mechanical recipes; SelfAdmin migration via
`IIdentityAugmenter`; `EnableRefreshTokens` default note.
- `README.md` index entries.
## Checklist
- [x] I have signed the
[CLA](https://opcfoundation.org/license/cla/ContributorLicenseAgreementv1.0.pdf)
and read the
[CONTRIBUTING](https://github.com/OPCFoundation/UA-.NETStandard/blob/master/CONTRIBUTING.md)
doc.
- [x] I have added tests that prove my fix is effective or that my
feature works and increased code coverage.
- [x] I have added all necessary documentation.
- [x] I have verified that my changes do not introduce (new) build or
analyzer warnings.
- [x] I ran **all** tests locally using the **UA.slnx** solution against
at least .net **framework** and .net **10**, and all passed.
- [x] I fixed **all** failing and flaky tests in the CI pipelines and
**all** CodeQL warnings.
- [x] I have addressed **all** PR feedback received.
Generate stack and application code using source generators
Change built in types to readonly structs
Update localized text implementation to use JSON text serializer
Status code with symbolic names
Immutable node ids
No boxing for all built in types <= 8 bytes in Variant.
Split user identity token and token handling via token handler
Add migration guide for breaking changes
Marc Schier