1 files changed, 71 insertions, 0 deletions
diff --git a/src/DotNetOpenAuth.OpenId.Provider/OpenId/Provider/HmacShaAssociationProvider.cs b/src/DotNetOpenAuth.OpenId.Provider/OpenId/Provider/HmacShaAssociationProvider.cs
new file mode 100644
index 0000000..3cfc0b6
--- /dev/null
+++ b/src/DotNetOpenAuth.OpenId.Provider/OpenId/Provider/HmacShaAssociationProvider.cs
@@ -0,0 +1,71 @@
+//-----------------------------------------------------------------------
+// <copyright file="HmacShaAssociationProvider.cs" company="Andrew Arnott">
+//     Copyright (c) Andrew Arnott. All rights reserved.
+// </copyright>
+//-----------------------------------------------------------------------
+
+namespace DotNetOpenAuth.OpenId.Provider {
+	using System;
+	using System.Collections.Generic;
+	using System.Diagnostics.Contracts;
+	using System.Linq;
+	using System.Text;
+	using DotNetOpenAuth.Messaging;
+	using DotNetOpenAuth.OpenId.Provider;
+
+	/// <summary>
+	/// OpenID Provider utility methods for HMAC-SHA* associations.
+	/// </summary>
+	internal static class HmacShaAssociationProvider {
+		/// <summary>
+		/// The default lifetime of a shared association when no lifetime is given
+		/// for a specific association type.
+		/// </summary>
+		private static readonly TimeSpan DefaultMaximumLifetime = TimeSpan.FromDays(14);
+
+		/// <summary>
+		/// Creates a new association of a given type at an OpenID Provider.
+		/// </summary>
+		/// <param name="protocol">The protocol.</param>
+		/// <param name="associationType">Type of the association (i.e. HMAC-SHA1 or HMAC-SHA256)</param>
+		/// <param name="associationUse">A value indicating whether the new association will be used privately by the Provider for "dumb mode" authentication
+		/// or shared with the Relying Party for "smart mode" authentication.</param>
+		/// <param name="associationStore">The Provider's association store.</param>
+		/// <param name="securitySettings">The security settings of the Provider.</param>
+		/// <returns>
+		/// The newly created association.
+		/// </returns>
+		/// <remarks>
+		/// The new association is NOT automatically put into an association store.  This must be done by the caller.
+		/// </remarks>
+		internal static HmacShaAssociation Create(Protocol protocol, string associationType, AssociationRelyingPartyType associationUse, IProviderAssociationStore associationStore, ProviderSecuritySettings securitySettings) {
+			Requires.NotNull(protocol, "protocol");
+			Requires.NotNullOrEmpty(associationType, "associationType");
+			Requires.NotNull(associationStore, "associationStore");
+			Requires.NotNull(securitySettings, "securitySettings");
+			Contract.Ensures(Contract.Result<HmacShaAssociation>() != null);
+
+			int secretLength = HmacShaAssociation.GetSecretLength(protocol, associationType);
+
+			// Generate the secret that will be used for signing
+			byte[] secret = MessagingUtilities.GetCryptoRandomData(secretLength);
+
+			TimeSpan lifetime;
+			if (associationUse == AssociationRelyingPartyType.Smart) {
+				if (!securitySettings.AssociationLifetimes.TryGetValue(associationType, out lifetime)) {
+					lifetime = DefaultMaximumLifetime;
+				}
+			} else {
+				lifetime = HmacShaAssociation.DumbSecretLifetime;
+			}
+
+			string handle = associationStore.Serialize(secret, DateTime.UtcNow + lifetime, associationUse == AssociationRelyingPartyType.Dumb);
+
+			Contract.Assert(protocol != null); // All the way up to the method call, the condition holds, yet we get a Requires failure next
+			Contract.Assert(secret != null);
+			Contract.Assert(!String.IsNullOrEmpty(associationType));
+			var result = HmacShaAssociation.Create(protocol, associationType, handle, secret, lifetime);
+			return result;
+		}
+	}
+}