Initial Commit

iTechSharp/srcbc/crypto/generators/OpenSSLPBEParametersGenerator.cs

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+using System;
+
+using Org.BouncyCastle.Crypto.Digests;
+using Org.BouncyCastle.Crypto.Parameters;
+using Org.BouncyCastle.Security;
+
+namespace Org.BouncyCastle.Crypto.Generators
+{
+	/**
+	 * Generator for PBE derived keys and ivs as usd by OpenSSL.
+	 * <p>
+	 * The scheme is a simple extension of PKCS 5 V2.0 Scheme 1 using MD5 with an
+	 * iteration count of 1.
+	 * </p>
+	 */
+	public class OpenSslPbeParametersGenerator
+		: PbeParametersGenerator
+	{
+		private readonly IDigest digest = new MD5Digest();
+
+		/**
+		 * Construct a OpenSSL Parameters generator. 
+		 */
+		public OpenSslPbeParametersGenerator()
+		{
+		}
+
+		public override void Init(
+			byte[]	password,
+			byte[]	salt,
+			int		iterationCount)
+		{
+			// Ignore the provided iterationCount
+			base.Init(password, salt, 1);
+		}
+
+		/**
+		 * Initialise - note the iteration count for this algorithm is fixed at 1.
+		 * 
+		 * @param password password to use.
+		 * @param salt salt to use.
+		 */
+		public virtual void Init(
+			byte[] password,
+			byte[] salt)
+		{
+			base.Init(password, salt, 1);
+		}
+
+		/**
+		 * the derived key function, the ith hash of the password and the salt.
+		 */
+		private byte[] GenerateDerivedKey(
+			int bytesNeeded)
+		{
+			byte[] buf = new byte[digest.GetDigestSize()];
+			byte[] key = new byte[bytesNeeded];
+			int offset = 0;
+        
+			for (;;)
+			{
+				digest.BlockUpdate(mPassword, 0, mPassword.Length);
+				digest.BlockUpdate(mSalt, 0, mSalt.Length);
+
+				digest.DoFinal(buf, 0);
+
+				int len = (bytesNeeded > buf.Length) ? buf.Length : bytesNeeded;
+				Array.Copy(buf, 0, key, offset, len);
+				offset += len;
+
+				// check if we need any more
+				bytesNeeded -= len;
+				if (bytesNeeded == 0)
+				{
+					break;
+				}
+
+				// do another round
+				digest.Reset();
+				digest.BlockUpdate(buf, 0, buf.Length);
+			}
+
+			return key;
+		}
+
+		/**
+		 * 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.
+		 * @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;
+
+			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.
+		 * @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 = keySize / 8;
+			ivSize = 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.
+		 * @exception ArgumentException if the key length larger than the base hash size.
+		 */
+		public override ICipherParameters GenerateDerivedMacParameters(
+			int keySize)
+		{
+			keySize = keySize / 8;
+
+			byte[] dKey = GenerateDerivedKey(keySize);
+
+			return new KeyParameter(dKey, 0, keySize);
+		}
+	}
+}