Initial Commit

iTechSharp/srcbc/bcpg/S2k.cs

@@ -0,0 +1,147 @@
+using System;
+using System.IO;
+
+using Org.BouncyCastle.Utilities;
+using Org.BouncyCastle.Utilities.IO;
+
+namespace Org.BouncyCastle.Bcpg
+{
+	/// <remarks>The string to key specifier class.</remarks>
+    public class S2k
+        : BcpgObject
+    {
+        private const int ExpBias = 6;
+
+        public const int Simple = 0;
+        public const int Salted = 1;
+        public const int SaltedAndIterated = 3;
+        public const int GnuDummyS2K = 101;
+
+        internal int type;
+        internal HashAlgorithmTag algorithm;
+        internal byte[] iv;
+        internal int itCount = -1;
+        internal int protectionMode = -1;
+
+        internal S2k(
+            Stream inStr)
+        {
+			type = inStr.ReadByte();
+            algorithm = (HashAlgorithmTag) inStr.ReadByte();
+
+            //
+            // if this happens we have a dummy-S2k packet.
+            //
+            if (type != GnuDummyS2K)
+            {
+                if (type != 0)
+                {
+					iv = new byte[8];
+					if (Streams.ReadFully(inStr, iv, 0, iv.Length) < iv.Length)
+						throw new EndOfStreamException();
+
+					if (type == 3)
+					{
+						itCount = inStr.ReadByte();
+					}
+				}
+            }
+            else
+            {
+                inStr.ReadByte(); // G
+                inStr.ReadByte(); // N
+                inStr.ReadByte(); // U
+                protectionMode = inStr.ReadByte(); // protection mode
+            }
+        }
+
+        public S2k(
+            HashAlgorithmTag algorithm)
+        {
+            this.type = 0;
+            this.algorithm = algorithm;
+        }
+
+        public S2k(
+            HashAlgorithmTag algorithm,
+            byte[] iv)
+        {
+            this.type = 1;
+            this.algorithm = algorithm;
+            this.iv = iv;
+        }
+
+        public S2k(
+            HashAlgorithmTag algorithm,
+            byte[] iv,
+            int itCount)
+        {
+            this.type = 3;
+            this.algorithm = algorithm;
+            this.iv = iv;
+            this.itCount = itCount;
+        }
+
+        public int Type
+        {
+			get { return type; }
+        }
+
+		/// <summary>The hash algorithm.</summary>
+        public HashAlgorithmTag HashAlgorithm
+        {
+			get { return algorithm; }
+		}
+
+		/// <summary>The IV for the key generation algorithm.</summary>
+        public byte[] GetIV()
+        {
+            return Arrays.Clone(iv);
+        }
+
+		[Obsolete("Use 'IterationCount' property instead")]
+        public long GetIterationCount()
+        {
+            return IterationCount;
+        }
+
+		/// <summary>The iteration count</summary>
+		public long IterationCount
+		{
+			get { return (16 + (itCount & 15)) << ((itCount >> 4) + ExpBias); }
+		}
+
+		/// <summary>The protection mode - only if GnuDummyS2K</summary>
+        public int ProtectionMode
+        {
+			get { return protectionMode; }
+        }
+
+        public override void Encode(
+            BcpgOutputStream bcpgOut)
+        {
+            bcpgOut.WriteByte((byte) type);
+            bcpgOut.WriteByte((byte) algorithm);
+
+            if (type != GnuDummyS2K)
+            {
+                if (type != 0)
+                {
+                    bcpgOut.Write(iv);
+                }
+
+                if (type == 3)
+                {
+                    bcpgOut.WriteByte((byte) itCount);
+                }
+            }
+            else
+            {
+                bcpgOut.WriteByte((byte) 'G');
+                bcpgOut.WriteByte((byte) 'N');
+                bcpgOut.WriteByte((byte) 'U');
+                bcpgOut.WriteByte((byte) protectionMode);
+            }
+        }
+    }
+}