Initial Commit

iTechSharp/srcbc/cms/PasswordRecipientInformation.cs

@@ -0,0 +1,74 @@
+using System;
+using System.IO;
+
+using Org.BouncyCastle.Asn1;
+using Org.BouncyCastle.Asn1.Cms;
+using Org.BouncyCastle.Asn1.X509;
+using Org.BouncyCastle.Crypto;
+using Org.BouncyCastle.Crypto.Parameters;
+using Org.BouncyCastle.Security;
+
+namespace Org.BouncyCastle.Cms
+{
+	/**
+	 * the RecipientInfo class for a recipient who has been sent a message
+	 * encrypted using a password.
+	 */
+	public class PasswordRecipientInformation
+		: RecipientInformation
+	{
+		private readonly PasswordRecipientInfo	_info;
+//		private readonly AlgorithmIdentifier	_encAlg;
+
+		public PasswordRecipientInformation(
+			PasswordRecipientInfo	info,
+			AlgorithmIdentifier		encAlg,
+			Stream					data)
+			: base(encAlg, AlgorithmIdentifier.GetInstance(info.KeyEncryptionAlgorithm), data)
+		{
+			this._info = info;
+//			this._encAlg = encAlg;
+			this._rid = new RecipientID();
+		}
+
+		/**
+		 * decrypt the content and return an input stream.
+		 */
+		public override CmsTypedStream GetContentStream(
+			ICipherParameters key)
+		{
+			try
+			{
+				AlgorithmIdentifier kekAlg = AlgorithmIdentifier.GetInstance(_info.KeyEncryptionAlgorithm);
+				Asn1Sequence        kekAlgParams = (Asn1Sequence)kekAlg.Parameters;
+				byte[]              encryptedKey = _info.EncryptedKey.GetOctets();
+				string              kekAlgName = DerObjectIdentifier.GetInstance(kekAlgParams[0]).Id;
+				string				cName = CmsEnvelopedHelper.Instance.GetRfc3211WrapperName(kekAlgName);
+				IWrapper			keyWrapper = WrapperUtilities.GetWrapper(cName);
+
+				byte[] iv = Asn1OctetString.GetInstance(kekAlgParams[1]).GetOctets();
+
+				ICipherParameters parameters = ((CmsPbeKey)key).GetEncoded(kekAlgName);
+				parameters = new ParametersWithIV(parameters, iv);
+
+				keyWrapper.Init(false, parameters);
+
+				AlgorithmIdentifier aid = _encAlg;
+				string alg = aid.ObjectID.Id;
+
+				KeyParameter sKey = ParameterUtilities.CreateKeyParameter(
+					alg, keyWrapper.Unwrap(encryptedKey, 0, encryptedKey.Length));
+
+				return GetContentFromSessionKey(sKey);
+			}
+			catch (SecurityUtilityException e)
+			{
+				throw new CmsException("couldn't create cipher.", e);
+			}
+			catch (InvalidKeyException e)
+			{
+				throw new CmsException("key invalid in message.", e);
+			}
+		}
+	}
+}