1 files changed, 39 insertions, 0 deletions
diff --git a/src/DotNetOpenAuth.Messaging/Messaging/Bindings/INonceStore.cs b/src/DotNetOpenAuth.Messaging/Messaging/Bindings/INonceStore.cs
new file mode 100644
index 0000000..6b6e2e1
--- /dev/null
+++ b/src/DotNetOpenAuth.Messaging/Messaging/Bindings/INonceStore.cs
@@ -0,0 +1,39 @@
+//-----------------------------------------------------------------------
+// <copyright file="INonceStore.cs" company="Andrew Arnott">
+//     Copyright (c) Andrew Arnott. All rights reserved.
+// </copyright>
+//-----------------------------------------------------------------------
+
+namespace DotNetOpenAuth.Messaging.Bindings {
+	using System;
+
+	/// <summary>
+	/// Describes the contract a nonce store must fulfill.
+	/// </summary>
+	public interface INonceStore {
+		/// <summary>
+		/// Stores a given nonce and timestamp.
+		/// </summary>
+		/// <param name="context">The context, or namespace, within which the 
+		/// <paramref name="nonce"/> must be unique.  
+		/// The context SHOULD be treated as case-sensitive.
+		/// The value will never be <c>null</c> but may be the empty string.</param>
+		/// <param name="nonce">A series of random characters.</param>
+		/// <param name="timestampUtc">The UTC timestamp that together with the nonce string make it unique
+		/// within the given <paramref name="context"/>.
+		/// The timestamp may also be used by the data store to clear out old nonces.</param>
+		/// <returns>
+		/// True if the context+nonce+timestamp (combination) was not previously in the database.
+		/// False if the nonce was stored previously with the same timestamp and context.
+		/// </returns>
+		/// <remarks>
+		/// The nonce must be stored for no less than the maximum time window a message may
+		/// be processed within before being discarded as an expired message.
+		/// This maximum message age can be looked up via the
+		/// <see cref="DotNetOpenAuth.Configuration.MessagingElement.MaximumMessageLifetime"/>
+		/// property, accessible via the <see cref="DotNetOpenAuth.Configuration.DotNetOpenAuthSection.Configuration"/>
+		/// property.
+		/// </remarks>
+		bool StoreNonce(string context, string nonce, DateTime timestampUtc);
+	}
+}