Initial Commit

iTechSharp/srcbc/crypto/generators/Pkcs5S2ParametersGenerator.cs

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+using System;
+
+using Org.BouncyCastle.Crypto;
+using Org.BouncyCastle.Crypto.Parameters;
+using Org.BouncyCastle.Crypto.Digests;
+using Org.BouncyCastle.Crypto.Macs;
+using Org.BouncyCastle.Math;
+using Org.BouncyCastle.Security;
+
+namespace Org.BouncyCastle.Crypto.Generators
+{
+	/**
+	* Generator for Pbe derived keys and ivs as defined by Pkcs 5 V2.0 Scheme 2.
+	* This generator uses a SHA-1 HMac as the calculation function.
+	* <p>
+	* The document this implementation is based on can be found at
+	* <a href="http://www.rsasecurity.com/rsalabs/pkcs/pkcs-5/index.html">
+	* RSA's Pkcs5 Page</a></p>
+	*/
+	public class Pkcs5S2ParametersGenerator
+		: PbeParametersGenerator
+	{
+		private readonly IMac hMac = new HMac(new Sha1Digest());
+
+		/**
+		* construct a Pkcs5 Scheme 2 Parameters generator.
+		*/
+		public Pkcs5S2ParametersGenerator()
+		{
+		}
+
+		private void F(
+			byte[]  P,
+			byte[]  S,
+			int     c,
+			byte[]  iBuf,
+			byte[]  outBytes,
+			int     outOff)
+		{
+			byte[]              state = new byte[hMac.GetMacSize()];
+			ICipherParameters    param = new KeyParameter(P);
+
+			hMac.Init(param);
+
+			if (S != null)
+			{
+				hMac.BlockUpdate(S, 0, S.Length);
+			}
+
+			hMac.BlockUpdate(iBuf, 0, iBuf.Length);
+
+			hMac.DoFinal(state, 0);
+
+			Array.Copy(state, 0, outBytes, outOff, state.Length);
+
+			for (int count = 1; count != c; count++)
+			{
+				hMac.Init(param);
+				hMac.BlockUpdate(state, 0, state.Length);
+				hMac.DoFinal(state, 0);
+
+				for (int j = 0; j != state.Length; j++)
+				{
+					outBytes[outOff + j] ^= state[j];
+				}
+			}
+		}
+
+		private void IntToOctet(
+			byte[]  Buffer,
+			int     i)
+		{
+			Buffer[0] = (byte)((uint) i >> 24);
+			Buffer[1] = (byte)((uint) i >> 16);
+			Buffer[2] = (byte)((uint) i >> 8);
+			Buffer[3] = (byte)i;
+		}
+
+		private byte[] GenerateDerivedKey(
+			int dkLen)
+		{
+			int     hLen = hMac.GetMacSize();
+			int     l = (dkLen + hLen - 1) / hLen;
+			byte[]  iBuf = new byte[4];
+			byte[]  outBytes = new byte[l * hLen];
+
+			for (int i = 1; i <= l; i++)
+			{
+				IntToOctet(iBuf, i);
+
+				F(mPassword, mSalt, mIterationCount, iBuf, outBytes, (i - 1) * hLen);
+			}
+
+			return outBytes;
+		}
+
+		/**
+		* Generate a key parameter derived from the password, salt, and iteration
+		* count we are currently initialised with.
+		*
+		* @param keySize the size of the key we want (in bits)
+		* @return a KeyParameter object.
+		*/
+		[Obsolete("Use version with 'algorithm' parameter")]
+		public override ICipherParameters GenerateDerivedParameters(
+			int keySize)
+		{
+			return GenerateDerivedMacParameters(keySize);
+		}
+
+		public override ICipherParameters GenerateDerivedParameters(
+			string	algorithm,
+			int		keySize)
+		{
+			keySize /= 8;
+
+			byte[] dKey = GenerateDerivedKey(keySize);
+
+			return ParameterUtilities.CreateKeyParameter(algorithm, dKey, 0, keySize);
+		}
+
+		/**
+		* Generate a key with initialisation vector parameter derived from
+		* the password, salt, and iteration count we are currently initialised
+		* with.
+		*
+		* @param keySize the size of the key we want (in bits)
+		* @param ivSize the size of the iv we want (in bits)
+		* @return a ParametersWithIV object.
+		*/
+		[Obsolete("Use version with 'algorithm' parameter")]
+		public override ICipherParameters GenerateDerivedParameters(
+			int	keySize,
+			int	ivSize)
+		{
+			keySize /= 8;
+			ivSize /= 8;
+
+			byte[] dKey = GenerateDerivedKey(keySize + ivSize);
+
+			return new ParametersWithIV(new KeyParameter(dKey, 0, keySize), dKey, keySize, ivSize);
+		}
+
+		public override ICipherParameters GenerateDerivedParameters(
+			string	algorithm,
+			int		keySize,
+			int		ivSize)
+		{
+			keySize /= 8;
+			ivSize /= 8;
+
+			byte[] dKey = GenerateDerivedKey(keySize + ivSize);
+			KeyParameter key = ParameterUtilities.CreateKeyParameter(algorithm, dKey, 0, keySize);
+
+			return new ParametersWithIV(key, dKey, keySize, ivSize);
+		}
+
+		/**
+		* Generate a key parameter for use with a MAC derived from the password,
+		* salt, and iteration count we are currently initialised with.
+		*
+		* @param keySize the size of the key we want (in bits)
+		* @return a KeyParameter object.
+		*/
+		public override ICipherParameters GenerateDerivedMacParameters(
+			int keySize)
+		{
+			keySize /= 8;
+
+			byte[] dKey = GenerateDerivedKey(keySize);
+
+			return new KeyParameter(dKey, 0, keySize);
+		}
+	}
+}