Replaces explicit crypto algorithm use with factories.

Fixes #47 which requires that FIPS compliance be an option.

1 files changed, 58 insertions, 0 deletions

diff --git a/src/DotNetOpenAuth.Core/Messaging/HmacAlgorithms.cs b/src/DotNetOpenAuth.Core/Messaging/HmacAlgorithms.cs
new file mode 100644
index 0000000..41dce81
--- /dev/null
+++ b/src/DotNetOpenAuth.Core/Messaging/HmacAlgorithms.cs
@@ -0,0 +1,58 @@
+//-----------------------------------------------------------------------
+// <copyright file="HmacAlgorithmNames.cs" company="Outercurve Foundation">
+//     Copyright (c) Outercurve Foundation. All rights reserved.
+// </copyright>
+//-----------------------------------------------------------------------
+
+namespace DotNetOpenAuth.Messaging {
+	using System;
+	using System.Collections.Generic;
+	using System.Linq;
+	using System.Security.Cryptography;
+	using System.Text;
+
+	/// <summary>
+	/// HMAC-SHA algorithm names that can be passed to the <see cref="HMAC.Create"/> method.
+	/// </summary>
+	internal static class HmacAlgorithms {
+		/// <summary>
+		/// The name of the HMAC-SHA1 algorithm.
+		/// </summary>
+		internal const string HmacSha1 = "HMACSHA1";
+
+		/// <summary>
+		/// The name of the HMAC-SHA256 algorithm.
+		/// </summary>
+		internal const string HmacSha256 = "HMACSHA256";
+
+		/// <summary>
+		/// The name of the HMAC-SHA384 algorithm.
+		/// </summary>
+		internal const string HmacSha384 = "HMACSHA384";
+
+		/// <summary>
+		/// The name of the HMAC-SHA512 algorithm.
+		/// </summary>
+		internal const string HmacSha512 = "HMACSHA512";
+
+		/// <summary>
+		/// Creates an HMAC-SHA algorithm with the specified name and key.
+		/// </summary>
+		/// <param name="algorithmName">A name from the available choices in the static const members of this class.</param>
+		/// <param name="key">The secret key used as the HMAC.</param>
+		/// <returns>The HMAC algorithm instance.</returns>
+		internal static HMAC Create(string algorithmName, byte[] key) {
+			Requires.NotNullOrEmpty(algorithmName, "algorithmName");
+			Requires.NotNull(key, "key");
+
+			HMAC hmac = HMAC.Create(algorithmName);
+			try {
+				hmac.Key = key;
+				return hmac;
+			} catch {
+				hmac.Dispose();
+				throw;
+			}
+		}
+	}
+}