Initial Commit

iTechSharp/srcbc/crypto/parameters/DesEdeParameters.cs

@@ -0,0 +1,95 @@
+using System;
+
+namespace Org.BouncyCastle.Crypto.Parameters
+{
+    public class DesEdeParameters
+		: DesParameters
+    {
+        /*
+        * DES-EDE Key length in bytes.
+        */
+		public const int DesEdeKeyLength = 24;
+
+		private static byte[] FixKey(
+			byte[]	key,
+			int		keyOff,
+			int		keyLen)
+		{
+			byte[] tmp = new byte[24];
+
+			switch (keyLen)
+			{
+				case 16:
+					Array.Copy(key, keyOff, tmp, 0, 16);
+					Array.Copy(key, keyOff, tmp, 16, 8);
+					break;
+				case 24:
+					Array.Copy(key, keyOff, tmp, 0, 24);
+					break;
+				default:
+					throw new ArgumentException("Bad length for DESede key: " + keyLen, "keyLen");
+			}
+
+			if (IsWeakKey(tmp))
+				throw new ArgumentException("attempt to create weak DESede key");
+
+			return tmp;
+		}
+
+		public DesEdeParameters(
+            byte[] key)
+			: base(FixKey(key, 0, key.Length))
+        {
+        }
+
+		public DesEdeParameters(
+			byte[]	key,
+			int		keyOff,
+			int		keyLen)
+			: base(FixKey(key, keyOff, keyLen))
+		{
+		}
+
+		/**
+         * return true if the passed in key is a DES-EDE weak key.
+         *
+         * @param key bytes making up the key
+         * @param offset offset into the byte array the key starts at
+         * @param length number of bytes making up the key
+         */
+        public static bool IsWeakKey(
+            byte[]  key,
+            int     offset,
+            int     length)
+        {
+            for (int i = offset; i < length; i += DesKeyLength)
+            {
+                if (DesParameters.IsWeakKey(key, i))
+                {
+                    return true;
+                }
+            }
+
+            return false;
+        }
+
+        /**
+         * return true if the passed in key is a DES-EDE weak key.
+         *
+         * @param key bytes making up the key
+         * @param offset offset into the byte array the key starts at
+         */
+        public static new bool IsWeakKey(
+            byte[]	key,
+            int		offset)
+        {
+            return IsWeakKey(key, offset, key.Length - offset);
+        }
+
+		public static new bool IsWeakKey(
+			byte[] key)
+		{
+			return IsWeakKey(key, 0, key.Length);
+		}
+    }
+}