Initial Commit

iTechSharp/srcbc/crypto/generators/Pkcs5S1ParametersGenerator.cs

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+using System;
+
+using Org.BouncyCastle.Crypto;
+using Org.BouncyCastle.Crypto.Digests;
+using Org.BouncyCastle.Crypto.Parameters;
+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 1.
+	* Note this generator is limited to the size of the hash produced by the
+	* digest used to drive it.
+	* <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 Pkcs5S1ParametersGenerator
+		: PbeParametersGenerator
+	{
+		private readonly IDigest digest;
+
+		/**
+		* Construct a Pkcs 5 Scheme 1 Parameters generator.
+		*
+		* @param digest the digest to be used as the source of derived keys.
+		*/
+		public Pkcs5S1ParametersGenerator(
+			IDigest digest)
+		{
+			this.digest = digest;
+		}
+
+		/**
+		* the derived key function, the ith hash of the mPassword and the mSalt.
+		*/
+		private byte[] GenerateDerivedKey()
+		{
+			byte[] digestBytes = new byte[digest.GetDigestSize()];
+
+			digest.BlockUpdate(mPassword, 0, mPassword.Length);
+			digest.BlockUpdate(mSalt, 0, mSalt.Length);
+
+			digest.DoFinal(digestBytes, 0);
+			for (int i = 1; i < mIterationCount; i++)
+			{
+				digest.BlockUpdate(digestBytes, 0, digestBytes.Length);
+				digest.DoFinal(digestBytes, 0);
+			}
+
+			return digestBytes;
+		}
+
+		/**
+		* Generate a key parameter derived from the mPassword, mSalt, and iteration
+		* count we are currently initialised with.
+		*
+		* @param keySize the size of the key we want (in bits)
+		* @return a KeyParameter object.
+		* @exception ArgumentException if the key length larger than the base hash size.
+		*/
+		[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;
+
+			if (keySize > digest.GetDigestSize())
+			{
+				throw new ArgumentException(
+					"Can't Generate a derived key " + keySize + " bytes long.");
+			}
+
+			byte[] dKey = GenerateDerivedKey();
+
+			return ParameterUtilities.CreateKeyParameter(algorithm, dKey, 0, keySize);
+		}
+
+		/**
+		* Generate a key with initialisation vector parameter derived from
+		* the mPassword, mSalt, 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.
+		* @exception ArgumentException if keySize + ivSize is larger than the base hash size.
+		*/
+		[Obsolete("Use version with 'algorithm' parameter")]
+		public override ICipherParameters GenerateDerivedParameters(
+			int	keySize,
+			int	ivSize)
+		{
+			keySize /= 8;
+			ivSize /= 8;
+
+			if ((keySize + ivSize) > digest.GetDigestSize())
+			{
+				throw new ArgumentException(
+					"Can't Generate a derived key " + (keySize + ivSize) + " bytes long.");
+			}
+
+			byte[] dKey = GenerateDerivedKey();
+
+			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;
+
+			if ((keySize + ivSize) > digest.GetDigestSize())
+			{
+				throw new ArgumentException(
+					"Can't Generate a derived key " + (keySize + ivSize) + " bytes long.");
+			}
+
+			byte[] dKey = GenerateDerivedKey();
+			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 mPassword,
+		* mSalt, and iteration count we are currently initialised with.
+		*
+		* @param keySize the size of the key we want (in bits)
+		* @return a KeyParameter object.
+		* @exception ArgumentException if the key length larger than the base hash size.
+		*/
+		public override ICipherParameters GenerateDerivedMacParameters(
+			int keySize)
+		{
+			keySize /= 8;
+
+			if (keySize > digest.GetDigestSize())
+			{
+				throw new ArgumentException(
+					"Can't Generate a derived key " + keySize + " bytes long.");
+			}
+
+			byte[] dKey = GenerateDerivedKey();
+
+			return new KeyParameter(dKey, 0, keySize);
+		}
+	}
+}