Initial Commit

iTechSharp/srcbc/cms/KeyTransRecipientInformation.cs

@@ -0,0 +1,111 @@
+using System;
+using System.IO;
+
+using Org.BouncyCastle.Asn1;
+using Org.BouncyCastle.Asn1.Cms;
+using Asn1Pkcs = Org.BouncyCastle.Asn1.Pkcs;
+using Org.BouncyCastle.Asn1.X509;
+using Org.BouncyCastle.Crypto;
+using Org.BouncyCastle.Crypto.Parameters;
+using Org.BouncyCastle.Security;
+using Org.BouncyCastle.X509;
+
+namespace Org.BouncyCastle.Cms
+{
+    /**
+    * the KeyTransRecipientInformation class for a recipient who has been sent a secret
+    * key encrypted using their public key that needs to be used to
+    * extract the message.
+    */
+    public class KeyTransRecipientInformation
+        : RecipientInformation
+    {
+        private KeyTransRecipientInfo _info;
+//        private new AlgorithmIdentifier   _encAlg;
+
+		public KeyTransRecipientInformation(
+            KeyTransRecipientInfo	info,
+            AlgorithmIdentifier		encAlg,
+            Stream					data)
+            : base(encAlg, AlgorithmIdentifier.GetInstance(info.KeyEncryptionAlgorithm), data)
+        {
+            this._info = info;
+//            this._encAlg = encAlg;
+            this._rid = new RecipientID();
+
+			RecipientIdentifier r = info.RecipientIdentifier;
+
+			try
+            {
+                if (r.IsTagged)
+                {
+                    Asn1OctetString octs = Asn1OctetString.GetInstance(r.ID);
+
+					_rid.SubjectKeyIdentifier = octs.GetOctets();
+                }
+                else
+                {
+                    IssuerAndSerialNumber iAnds = IssuerAndSerialNumber.GetInstance(r.ID);
+
+					_rid.Issuer = iAnds.Name;
+                    _rid.SerialNumber = iAnds.SerialNumber.Value;
+                }
+            }
+            catch (IOException)
+            {
+                throw new ArgumentException("invalid rid in KeyTransRecipientInformation");
+            }
+        }
+
+		private string GetExchangeEncryptionAlgorithmName(
+			DerObjectIdentifier oid)
+		{
+			if (Asn1Pkcs.PkcsObjectIdentifiers.RsaEncryption.Equals(oid))
+			{
+				return "RSA//PKCS1Padding";
+			}
+
+			return oid.Id;
+		}
+
+		/**
+        * decrypt the content and return it as a byte array.
+        */
+        public override CmsTypedStream GetContentStream(
+            ICipherParameters key)
+        {
+			byte[] encryptedKey = _info.EncryptedKey.GetOctets();
+			string keyExchangeAlgorithm = GetExchangeEncryptionAlgorithmName(_keyEncAlg.ObjectID);
+
+			try
+			{
+				IWrapper keyWrapper = WrapperUtilities.GetWrapper(keyExchangeAlgorithm);
+
+				keyWrapper.Init(false, key);
+
+				KeyParameter sKey = ParameterUtilities.CreateKeyParameter(
+					_encAlg.ObjectID, 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);
+			}
+//			catch (IllegalBlockSizeException e)
+			catch (DataLengthException e)
+			{
+				throw new CmsException("illegal blocksize in message.", e);
+			}
+//			catch (BadPaddingException e)
+			catch (InvalidCipherTextException e)
+			{
+				throw new CmsException("bad padding in message.", e);
+			}
+		}
+    }
+}