1 files changed, 114 insertions, 0 deletions
diff --git a/Crypto/src/crypto/tls/Ssl3Mac.cs b/Crypto/src/crypto/tls/Ssl3Mac.cs
new file mode 100644
index 000000000..b2f3f309e
--- /dev/null
+++ b/Crypto/src/crypto/tls/Ssl3Mac.cs
@@ -0,0 +1,114 @@
+using System;
+
+using Org.BouncyCastle.Crypto;
+using Org.BouncyCastle.Crypto.Parameters;
+using Org.BouncyCastle.Utilities;
+
+namespace Org.BouncyCastle.Crypto.Tls
+{
+	/**
+	 * HMAC implementation based on original internet draft for HMAC (RFC 2104)
+	 * 
+	 * The difference is that padding is concatentated versus XORed with the key
+	 * 
+	 * H(K + opad, H(K + ipad, text))
+	 */
+	public class Ssl3Mac
+		: IMac
+	{
+		private const byte IPAD = 0x36;
+		private const byte OPAD = 0x5C;
+
+		internal static readonly byte[] MD5_IPAD = GenPad(IPAD, 48);
+		internal static readonly byte[] MD5_OPAD = GenPad(OPAD, 48);
+		internal static readonly byte[] SHA1_IPAD = GenPad(IPAD, 40);
+		internal static readonly byte[] SHA1_OPAD = GenPad(OPAD, 40);
+
+		private IDigest digest;
+
+		private byte[] secret;
+		private byte[] ipad, opad;
+
+		/**
+		 * Base constructor for one of the standard digest algorithms that the byteLength of
+		 * the algorithm is know for. Behaviour is undefined for digests other than MD5 or SHA1.
+		 * 
+		 * @param digest the digest.
+		 */
+		public Ssl3Mac(IDigest digest)
+		{
+			this.digest = digest;
+
+	        if (digest.GetDigestSize() == 20)
+	        {
+	            this.ipad = SHA1_IPAD;
+	            this.opad = SHA1_OPAD;
+	        }
+	        else
+	        {
+	            this.ipad = MD5_IPAD;
+	            this.opad = MD5_OPAD;
+	        }
+		}
+
+		public virtual string AlgorithmName
+		{
+			get { return digest.AlgorithmName + "/SSL3MAC"; }
+		}
+
+		public virtual void Init(ICipherParameters parameters)
+		{
+			secret = Arrays.Clone(((KeyParameter)parameters).GetKey());
+
+			Reset();
+		}
+
+		public virtual int GetMacSize()
+		{
+			return digest.GetDigestSize();
+		}
+
+		public virtual void Update(byte input)
+		{
+			digest.Update(input);
+		}
+
+		public virtual void BlockUpdate(byte[] input, int inOff, int len)
+		{
+			digest.BlockUpdate(input, inOff, len);
+		}
+
+		public virtual int DoFinal(byte[] output, int outOff)
+		{
+			byte[] tmp = new byte[digest.GetDigestSize()];
+			digest.DoFinal(tmp, 0);
+
+			digest.BlockUpdate(secret, 0, secret.Length);
+			digest.BlockUpdate(opad, 0, opad.Length);
+			digest.BlockUpdate(tmp, 0, tmp.Length);
+
+			int len = digest.DoFinal(output, outOff);
+
+			Reset();
+
+			return len;
+		}
+
+		/**
+		 * Reset the mac generator.
+		 */
+		public virtual void Reset()
+		{
+			digest.Reset();
+			digest.BlockUpdate(secret, 0, secret.Length);
+			digest.BlockUpdate(ipad, 0, ipad.Length);
+		}
+
+		private static byte[] GenPad(byte b, int count)
+		{
+			byte[] padding = new byte[count];
+			Arrays.Fill(padding, b);
+			return padding;
+		}
+	}
+}