Adds an abstraction over the CreateChallengeRequest.complexity field
(already present in the proto since the original altcha module landed),
letting applications scale PoW difficulty per request based on actor
signals — repeat-offender counters, threat-intel headers, reputation
scores — without leaking those concerns into the gRPC provider.
- new IAltchaDifficultyAdvisor in Svrnty.CQRS.Altcha.Abstractions:
Task<uint?> GetComplexityAsync(...). null means "use the upstream
service's configured default."
- NullAltchaDifficultyAdvisor in Svrnty.CQRS.Altcha is the no-op
fallback registered by AddSvrntyAltcha() via TryAddSingleton, so
applications can replace it without ordering constraints.
- AltchaGrpcChallengeProvider now resolves the advisor and sets
CreateChallengeRequest.Complexity when the advisor returns a value.
The Altcha server clamps to its configured min/max, so callers
don't need to enforce bounds here.
No breaking changes to existing consumers — the no-op default keeps
behaviour identical when no advisor is registered.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
The Altcha authorization check, plugged into the
ICommandAuthorizationCheck / IQueryAuthorizationCheck seam.
Behavior
- Self-applies: returns Allowed for any request whose type isn't
decorated with [Altcha]. No-op for the 99% of endpoints that don't
need PoW.
- Reads ctx.Items["mobile_attested"] for Phase 3 bypass when the
attribute's AllowMobileAttestationBypass is true.
- Pulls the solution off the request via IHasAltchaSolution and
delegates verification to IAltchaVerifier (resolved per-call from
the request scope, so any verifier lifetime works).
- Stashes a diagnostic reason in ctx.Items["altcha_reason"]
(missing / misconfigured / invalid / replayed / expired / etc.)
for downstream middleware to surface in error responses.
- Singleton itself — stateless; one instance shared via factory
registrations under both check interfaces.
AddSvrntyAltcha() registers the check. The verifier is provided by
a transport-specific module (e.g. Svrnty.CQRS.Altcha.Grpc, next).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
