Table of Contents

AsiBackbone 5.0.0 Release Notes

5.0.0 starts the stable 5.x AsiBackbone package family. It advances the binary assembly identity to 5.0.0.0. Package IDs, public namespaces, and the net10.0 target remain unchanged.

This is a security release. It resolves twelve findings from the September 2026 cross-repository review, including one critical and one high. Every behavior change makes a governance path fail closed where it previously returned a permissive result, which is why the work takes a major-version boundary rather than a patch.

Consumers upgrading from 4.0.0 should follow the 4.0.0 to 5.0.0 Migration Guide. The enum renumbering described there needs a data migration for hosts that persist those values as integers.

Verification binds artifact content to its signature

GovernanceArtifactVerifier.VerifyAsync recomputes the canonical payload hash and denies when the payload does not hash to the signed value. Verification previously compared two values the artifact carried about itself and forwarded that self-reported hash to the provider, so the signature was checked against a stored hash rather than against the content being evaluated. A caller that rehydrated a signed artifact from storage or a queue could present modified content beside an authentic hash and signature pair and receive a valid, allowed outcome.

SignedGovernanceArtifacts.Rehydrate applies the same check at construction for artifacts rebuilt from storage.

Capability proofs bind to the grant being evaluated

CapabilityGrantValidator.ValidateAsync rebuilds the canonical payload from the grant it is about to evaluate, compares that hash to the signed hash, and asserts the signed artifact type and token identifier. Without those checks a proof covering a narrower grant, or a validly signed hash from a different artifact type, could be attached to a supplied grant whose issuer, audience, scopes, expiry, and bindings the validator then read.

Audit chains anchor and detect truncation

AuditIntegrityVerifier.Verify takes expectedPreviousLinkHash and fails closed when a non-genesis partial chain supplies no anchor. It previously seeded the expected previous hash with an empty string regardless of requireGenesis, rejecting genuine partial chains while accepting a forged restart whose links were rewritten to claim no predecessor.

expectedTipLinkHash and expectedTipSequence report a TruncatedChain when the supplied links form a valid prefix that does not reach the expected tip.

Permissive defaults now deny

  • Omitted capability validation options deny instead of validating an unexpired grant against nothing.
  • Requiring proof or a bounded-use check without an audience expectation is refused.
  • A key outside the configured pin reports signature.key-not-trusted under the new UntrustedKey category and denies, rather than escalating more softly than a bad signature.
  • A stripped signature denies when proof is required.
  • Mapping a failure category to Allow requires an explicit unsafe opt-in.
  • Zero is a rejected Unspecified sentinel in VerificationPolicyAction, SignatureVerificationCategory, GrantUseState, and AuditIntegrityVerificationCategory.

Provider and host boundaries

  • ManagedKeySigningService rejects a response whose key identifier, key version, or signature algorithm differs from the request.
  • UseLocalDevelopmentSigning throws in Production unless AllowInProduction is set, and the new ASIB003 analyzer diagnostic reports registrations with no environment guard at all.
  • GovernanceArtifactSigner.Sign*Async throws when the provider returns no signature, unless requireSignature: false is passed.

Personal data and durable rows

Email claims are no longer default actor-id or display-name sources. Actor identifiers and display names are persisted verbatim and indexed in durable audit rows, so the framework's own defaults placed personal data there while the security guidance told hosts to keep it out.

Capability use limits can be bound at issuance

CapabilityTokenGrant can carry the use limit its issuer authorized, and validation uses the narrower of that limit and any limit the caller supplies. A grant recording AsiBackboneSchemaVersions.StableArtifactsV1 canonicalizes exactly as it did in 4.x, so grants signed before this release keep verifying.

Other hardening

  • Canonical payload metadata keys that collide after trimming are rejected rather than resolved by enumeration order.
  • The web API template's sample capability validator compares the scopes a caller presented against the scopes an endpoint requires instead of comparing the endpoint's declaration against itself, and its audit-residue endpoint carries its own capability requirement.
  • InMemoryCapabilityGrantUseStore keys use records by issuer and token identifier and evicts records for long-expired grants.

Durable release evidence

The v5.0.0 GitHub release retains its package SBOMs, sbom-manifest.json, release-evidence-manifest.json, and a Markdown copy of these release notes as durable public assets. See the release asset list and the 5.0.0 Consumer Verification Guide for subject-digest provenance verification commands.

NuGet package signing remains deferred under the dated NuGet Package Signing Decision Record.

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