1 files changed, 112 insertions, 0 deletions
diff --git a/Crypto/src/cms/CMSAuthEnvelopedData.cs b/Crypto/src/cms/CMSAuthEnvelopedData.cs
new file mode 100644
index 000000000..d35e946ae
--- /dev/null
+++ b/Crypto/src/cms/CMSAuthEnvelopedData.cs
@@ -0,0 +1,112 @@
+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.Parameters;
+
+namespace Org.BouncyCastle.Cms
+{
+	/**
+	* containing class for an CMS AuthEnveloped Data object
+	*/
+	internal class CmsAuthEnvelopedData
+	{
+		internal RecipientInformationStore recipientInfoStore;
+		internal ContentInfo contentInfo;
+
+		private OriginatorInfo      originator;
+		private AlgorithmIdentifier authEncAlg;
+		private Asn1Set             authAttrs;
+		private byte[]              mac;
+		private Asn1Set             unauthAttrs;
+	
+		public CmsAuthEnvelopedData(
+			byte[] authEnvData)
+			: this(CmsUtilities.ReadContentInfo(authEnvData))
+		{
+		}
+
+		public CmsAuthEnvelopedData(
+			Stream authEnvData)
+			: this(CmsUtilities.ReadContentInfo(authEnvData))
+		{
+		}
+
+		public CmsAuthEnvelopedData(
+			ContentInfo contentInfo)
+		{
+			this.contentInfo = contentInfo;
+
+			AuthEnvelopedData authEnvData = AuthEnvelopedData.GetInstance(contentInfo.Content);
+
+			this.originator = authEnvData.OriginatorInfo;
+
+			//
+	        // read the recipients
+	        //
+	        Asn1Set recipientInfos = authEnvData.RecipientInfos;
+
+			//
+			// read the auth-encrypted content info
+			//
+			EncryptedContentInfo authEncInfo = authEnvData.AuthEncryptedContentInfo;
+			this.authEncAlg = authEncInfo.ContentEncryptionAlgorithm;
+			CmsSecureReadable secureReadable = new AuthEnvelopedSecureReadable(this);
+
+			//
+			// build the RecipientInformationStore
+			//
+			this.recipientInfoStore = CmsEnvelopedHelper.BuildRecipientInformationStore(
+				recipientInfos, secureReadable);
+
+			// FIXME These need to be passed to the AEAD cipher as AAD (Additional Authenticated Data)
+			this.authAttrs = authEnvData.AuthAttrs;
+			this.mac = authEnvData.Mac.GetOctets();
+			this.unauthAttrs = authEnvData.UnauthAttrs;
+		}
+
+		private class AuthEnvelopedSecureReadable : CmsSecureReadable
+		{
+			private readonly CmsAuthEnvelopedData parent;
+
+			internal AuthEnvelopedSecureReadable(CmsAuthEnvelopedData parent)
+			{
+				this.parent = parent;
+			}
+
+			public AlgorithmIdentifier Algorithm
+			{
+				get { return parent.authEncAlg; }
+			}
+
+			public object CryptoObject
+			{
+				get { return null; }
+			}
+
+			public CmsReadable GetReadable(KeyParameter key)
+			{
+				// TODO Create AEAD cipher instance to decrypt and calculate tag ( MAC)
+				throw new CmsException("AuthEnveloped data decryption not yet implemented");
+
+//				RFC 5084 ASN.1 Module
+//				-- Parameters for AlgorithmIdentifier
+//				
+//				CCMParameters ::= SEQUENCE {
+//				  aes-nonce         OCTET STRING (SIZE(7..13)),
+//				  aes-ICVlen        AES-CCM-ICVlen DEFAULT 12 }
+//				
+//				AES-CCM-ICVlen ::= INTEGER (4 | 6 | 8 | 10 | 12 | 14 | 16)
+//				
+//				GCMParameters ::= SEQUENCE {
+//				  aes-nonce        OCTET STRING, -- recommended size is 12 octets
+//				  aes-ICVlen       AES-GCM-ICVlen DEFAULT 12 }
+//				
+//				AES-GCM-ICVlen ::= INTEGER (12 | 13 | 14 | 15 | 16)
+			}            
+		}
+	}
+}