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RollingHmacNonceService Class

Abblix.Oidc.Server​

Abblix.Oidc.Server.Features.Nonces​

RollingHmacNonceService Class​

HMAC-SHA256 backed implementation of INonceService. Issues stateless nonces of the form Base64Url(timestamp_8B || HMAC-SHA256(secret, timestamp_8B)[..16]) where secret is rotated on a configurable cadence and shared across server instances via Microsoft.Extensions.Caching.Distributed.IDistributedCache, keyed by time bucket.

public class RollingHmacNonceService : Abblix.Oidc.Server.Features.Nonces.INonceService

Inheritance System.Object → RollingHmacNonceService

Implements INonceService

Remarks​

The bucketed-secret design avoids any explicit lock or coordination on the rotation boundary: every instance derives the same bucket index from the nonce's embedded timestamp, looks up that bucket's secret in the distributed cache, and either finds it or creates one with last-write-wins semantics. Per RFC 9449 §11.3 a brief mismatch during the rotation race surfaces to the DPoP client as a single retry with a fresh DPoP-Nonce header, which is the protocol's intended recovery path; other consumers of this service get the analogous one-retry behaviour through their own challenge-response loop.

Constructors​

RollingHmacNonceService(ILogger<RollingHmacNonceService>, IDistributedCache, IOptionsMonitor<OidcOptions>, TimeProvider) Constructor​

HMAC-SHA256 backed implementation of INonceService. Issues stateless nonces of the form Base64Url(timestamp_8B || HMAC-SHA256(secret, timestamp_8B)[..16]) where secret is rotated on a configurable cadence and shared across server instances via Microsoft.Extensions.Caching.Distributed.IDistributedCache, keyed by time bucket.

public RollingHmacNonceService(Microsoft.Extensions.Logging.ILogger<Abblix.Oidc.Server.Features.Nonces.RollingHmacNonceService> logger, Microsoft.Extensions.Caching.Distributed.IDistributedCache cache, Microsoft.Extensions.Options.IOptionsMonitor<Abblix.Oidc.Server.Common.Configuration.OidcOptions> options, System.TimeProvider timeProvider);

Parameters​

logger Microsoft.Extensions.Logging.ILogger<RollingHmacNonceService>​
cache Microsoft.Extensions.Caching.Distributed.IDistributedCache​
options Microsoft.Extensions.Options.IOptionsMonitor<OidcOptions>​
timeProvider System.TimeProvider​

Remarks​

The bucketed-secret design avoids any explicit lock or coordination on the rotation boundary: every instance derives the same bucket index from the nonce's embedded timestamp, looks up that bucket's secret in the distributed cache, and either finds it or creates one with last-write-wins semantics. Per RFC 9449 §11.3 a brief mismatch during the rotation race surfaces to the DPoP client as a single retry with a fresh DPoP-Nonce header, which is the protocol's intended recovery path; other consumers of this service get the analogous one-retry behaviour through their own challenge-response loop.

Methods​

RollingHmacNonceService.IssueAsync(CancellationToken) Method​

Mints a fresh nonce string suitable for the DPoP-Nonce response header. The returned value is opaque to callers — clients must echo it verbatim.

public System.Threading.Tasks.Task<string> IssueAsync(System.Threading.CancellationToken cancellationToken=default(System.Threading.CancellationToken));

Parameters​

cancellationToken System.Threading.CancellationToken​

Implements IssueAsync(CancellationToken)

Returns​

System.Threading.Tasks.Task<System.String>

RollingHmacNonceService.ValidateAsync(string, CancellationToken) Method​

Verifies that nonce was issued by this deployment and is still within the acceptance window.

public System.Threading.Tasks.Task<System.Nullable<Abblix.Oidc.Server.Features.Nonces.NonceValidationFailure>> ValidateAsync(string nonce, System.Threading.CancellationToken cancellationToken=default(System.Threading.CancellationToken));

Parameters​

nonce System.String​

The nonce string echoed by the client in its DPoP proof nonce claim.

cancellationToken System.Threading.CancellationToken​

Cancellation token.

Implements ValidateAsync(string, CancellationToken)

Returns​

System.Threading.Tasks.Task<System.Nullable<NonceValidationFailure>>
null when the nonce is acceptable, otherwise a NonceValidationFailure describing why it is not.