HMACSHA512.cs

//
// HMACSHA512.cs: HMAC implementation using SHA512
//
// Author:
//	Sebastien Pouliot  <sebastien@xamarin.com>
//
// (C) 2003 Motus Technologies Inc. (http://www.motus.com)
// Copyright (C) 2004-2005, 2007 Novell, Inc (http://www.novell.com)
// Copyright 2013 Xamarin Inc. (http://www.xamarin.com)
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
// 
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//

using System.Runtime.InteropServices;

namespace SSMono.Security.Cryptography
	{
	[ComVisible (true)]
	public class HMACSHA512 : HMAC
		{
		private bool legacy;

#if !FULL_AOT_RUNTIME
		private static bool legacy_mode;

		static HMACSHA512 ()
			{
#if SSHARP
			legacy_mode = false;
#else
			legacy_mode = (Environment.GetEnvironmentVariable ("legacyHMACMode") == "1");
#endif
			}
#endif

		public HMACSHA512 ()
			: this (KeyBuilder.Key (8))
			{
			}

		public HMACSHA512 (byte[] key)
			{
#if FULL_AOT_RUNTIME
			BlockSizeValue = 128;
			SetHash ("SHA512", new SHA512Managed ());
#else
			ProduceLegacyHmacValues = legacy_mode;
			HashName = "SHA512";
#endif
			HashSizeValue = 512;
			Key = key;
			}

		// this property will appear in the next .NET service pack
		// http://blogs.msdn.com/shawnfa/archive/2007/01/31/please-do-not-use-the-net-2-0-hmacsha512-and-hmacsha384-classes.aspx
		public bool ProduceLegacyHmacValues
			{
			get { return legacy; }
			set
				{
				legacy = value;
				BlockSizeValue = legacy ? 64 : 128;
				}
			}
		}
	}