1 files changed, 161 insertions, 0 deletions
diff --git a/crypto/src/cms/CMSEnvelopedDataParser.cs b/crypto/src/cms/CMSEnvelopedDataParser.cs
new file mode 100644
index 000000000..01a949d47
--- /dev/null
+++ b/crypto/src/cms/CMSEnvelopedDataParser.cs
@@ -0,0 +1,161 @@
+using System;
+using System.Collections;
+using System.IO;
+
+using Org.BouncyCastle.Asn1;
+using Org.BouncyCastle.Asn1.Cms;
+using Org.BouncyCastle.Asn1.X509;
+using Org.BouncyCastle.Crypto;
+
+namespace Org.BouncyCastle.Cms
+{
+	/**
+	* Parsing class for an CMS Enveloped Data object from an input stream.
+	* <p>
+	* Note: that because we are in a streaming mode only one recipient can be tried and it is important
+	* that the methods on the parser are called in the appropriate order.
+	* </p>
+	* <p>
+	* Example of use - assuming the first recipient matches the private key we have.
+	* <pre>
+	*      CmsEnvelopedDataParser     ep = new CmsEnvelopedDataParser(inputStream);
+	*
+	*      RecipientInformationStore  recipients = ep.GetRecipientInfos();
+	*
+	*      Collection  c = recipients.getRecipients();
+	*      Iterator    it = c.iterator();
+	*
+	*      if (it.hasNext())
+	*      {
+	*          RecipientInformation   recipient = (RecipientInformation)it.next();
+	*
+	*          CMSTypedStream recData = recipient.getContentStream(privateKey);
+	*
+	*          processDataStream(recData.getContentStream());
+	*      }
+	*  </pre>
+	*  Note: this class does not introduce buffering - if you are processing large files you should create
+	*  the parser with:
+	*  <pre>
+	*          CmsEnvelopedDataParser     ep = new CmsEnvelopedDataParser(new BufferedInputStream(inputStream, bufSize));
+	*  </pre>
+	*  where bufSize is a suitably large buffer size.
+	* </p>
+	*/
+	public class CmsEnvelopedDataParser
+		: CmsContentInfoParser
+	{
+		internal RecipientInformationStore	recipientInfoStore;
+		internal EnvelopedDataParser		envelopedData;
+
+		private AlgorithmIdentifier			_encAlg;
+		private Asn1.Cms.AttributeTable		_unprotectedAttributes;
+		private bool						_attrNotRead;
+
+		public CmsEnvelopedDataParser(
+			byte[] envelopedData)
+			: this(new MemoryStream(envelopedData, false))
+		{
+		}
+
+		public CmsEnvelopedDataParser(
+			Stream envelopedData)
+			: base(envelopedData)
+		{
+			this._attrNotRead = true;
+			this.envelopedData = new EnvelopedDataParser(
+				(Asn1SequenceParser)this.contentInfo.GetContent(Asn1Tags.Sequence));
+
+			// TODO Validate version?
+			//DerInteger version = this.envelopedData.Version;
+
+			//
+			// read the recipients
+			//
+			Asn1Set recipientInfos = Asn1Set.GetInstance(this.envelopedData.GetRecipientInfos().ToAsn1Object());
+
+			//
+			// read the encrypted content info
+			//
+			EncryptedContentInfoParser encInfo = this.envelopedData.GetEncryptedContentInfo();
+			this._encAlg = encInfo.ContentEncryptionAlgorithm;
+			CmsReadable readable = new CmsProcessableInputStream(
+				((Asn1OctetStringParser)encInfo.GetEncryptedContent(Asn1Tags.OctetString)).GetOctetStream());
+			CmsSecureReadable secureReadable = new CmsEnvelopedHelper.CmsEnvelopedSecureReadable(
+				this._encAlg, readable);
+
+			//
+			// build the RecipientInformationStore
+			//
+			this.recipientInfoStore = CmsEnvelopedHelper.BuildRecipientInformationStore(
+				recipientInfos, secureReadable);
+		}
+
+		public AlgorithmIdentifier EncryptionAlgorithmID
+		{
+			get { return _encAlg; }
+		}
+
+		/**
+		 * return the object identifier for the content encryption algorithm.
+		 */
+		public string EncryptionAlgOid
+		{
+			get { return _encAlg.ObjectID.Id; }
+		}
+
+		/**
+		 * return the ASN.1 encoded encryption algorithm parameters, or null if
+		 * there aren't any.
+		 */
+		public Asn1Object EncryptionAlgParams
+		{
+			get
+			{
+				Asn1Encodable ae = _encAlg.Parameters;
+
+				return ae == null ? null : ae.ToAsn1Object();
+			}
+		}
+
+		/**
+		 * return a store of the intended recipients for this message
+		 */
+		public RecipientInformationStore GetRecipientInfos()
+		{
+			return this.recipientInfoStore;
+		}
+
+		/**
+		 * return a table of the unprotected attributes indexed by
+		 * the OID of the attribute.
+		 * @throws IOException
+		 */
+		public Asn1.Cms.AttributeTable GetUnprotectedAttributes()
+		{
+			if (_unprotectedAttributes == null && _attrNotRead)
+			{
+				Asn1SetParser asn1Set = this.envelopedData.GetUnprotectedAttrs();
+
+				_attrNotRead = false;
+
+				if (asn1Set != null)
+				{
+					Asn1EncodableVector v = new Asn1EncodableVector();
+					IAsn1Convertible o;
+
+					while ((o = asn1Set.ReadObject()) != null)
+					{
+						Asn1SequenceParser seq = (Asn1SequenceParser)o;
+
+						v.Add(seq.ToAsn1Object());
+					}
+
+					_unprotectedAttributes = new Asn1.Cms.AttributeTable(new DerSet(v));
+				}
+			}
+
+			return _unprotectedAttributes;
+		}
+	}
+}