context: using System;
  
  using Org.BouncyCastle.Utilities;
  
  namespace Org.BouncyCastle.Asn1.Cms
  {
  	public class AuthEnvelopedData
  		: Asn1Encodable
  	{
  		private DerInteger				version;
  		private OriginatorInfo			originatorInfo;
  		private Asn1Set					recipientInfos;
  		private EncryptedContentInfo	authEncryptedContentInfo;
  		private Asn1Set					authAttrs;
  		private Asn1OctetString			mac;
  		private Asn1Set					unauthAttrs;
  
  		public AuthEnvelopedData(
  			OriginatorInfo			originatorInfo,
  			Asn1Set					recipientInfos,
  			EncryptedContentInfo	authEncryptedContentInfo,
  			Asn1Set					authAttrs,
  			Asn1OctetString			mac,
  			Asn1Set					unauthAttrs)
  		{
  			// "It MUST be set to 0."
  			this.version = new DerInteger(0);
  
  			this.originatorInfo = originatorInfo;
  
  			// TODO
  			// "There MUST be at least one element in the collection."
  			this.recipientInfos = recipientInfos;
  
  			this.authEncryptedContentInfo = authEncryptedContentInfo;
  
  			// TODO
  			// "The authAttrs MUST be present if the content type carried in
  			// EncryptedContentInfo is not id-data."
  			this.authAttrs = authAttrs;
  
  			this.mac = mac;
  
  			this.unauthAttrs = unauthAttrs;
  	    }
  
  		private AuthEnvelopedData(
  			Asn1Sequence	seq)
  		{
  			int index = 0;
  
  			// TODO
  			// "It MUST be set to 0."
  			Asn1Object tmp = seq[index++].ToAsn1Object();
  			version = (DerInteger)tmp;
  
  			tmp = seq[index++].ToAsn1Object();
  			if (tmp is Asn1TaggedObject)
  			{
  				originatorInfo = OriginatorInfo.GetInstance((Asn1TaggedObject)tmp, false);
  				tmp = seq[index++].ToAsn1Object();
  			}
  
  			// TODO
  			// "There MUST be at least one element in the collection."
  			recipientInfos = Asn1Set.GetInstance(tmp);
  
  			tmp = seq[index++].ToAsn1Object();
  			authEncryptedContentInfo = EncryptedContentInfo.GetInstance(tmp);
  
  			tmp = seq[index++].ToAsn1Object();
  			if (tmp is Asn1TaggedObject)
  			{
  				authAttrs = Asn1Set.GetInstance((Asn1TaggedObject)tmp, false);
  				tmp = seq[index++].ToAsn1Object();
  			}
  			else
  			{
  				// TODO
  				// "The authAttrs MUST be present if the content type carried in
  				// EncryptedContentInfo is not id-data."
  			}
  
  			mac = Asn1OctetString.GetInstance(tmp);
  
  			if (seq.Count > index)
  			{
  				tmp = seq[index++].ToAsn1Object();
  				unauthAttrs = Asn1Set.GetInstance((Asn1TaggedObject)tmp, false);
  			}
  		}
  
  		/**
  		 * return an AuthEnvelopedData object from a tagged object.
  		 *
  		 * @param obj      the tagged object holding the object we want.
  		 * @param isExplicit true if the object is meant to be explicitly
  		 *                 tagged false otherwise.
  		 * @throws ArgumentException if the object held by the
  		 *                                  tagged object cannot be converted.
  		 */
  		public static AuthEnvelopedData GetInstance(
  			Asn1TaggedObject	obj,
  			bool				isExplicit)
  		{
  			return GetInstance(Asn1Sequence.GetInstance(obj, isExplicit));
  		}
  
  		/**
  		 * return an AuthEnvelopedData object from the given object.
  		 *
  		 * @param obj the object we want converted.
  		 * @throws ArgumentException if the object cannot be converted.
  		 */
  		public static AuthEnvelopedData GetInstance(
  			object	obj)
  		{
  			if (obj == null || obj is AuthEnvelopedData)
  				return (AuthEnvelopedData)obj;
  
  			if (obj is Asn1Sequence)
  				return new AuthEnvelopedData((Asn1Sequence)obj);
  
              throw new ArgumentException("Invalid AuthEnvelopedData: " + Platform.GetTypeName(obj));
  		}
  
  		public DerInteger Version
  		{
  			get { return version; }
  		}
  
  		public OriginatorInfo OriginatorInfo
  		{
  			get { return originatorInfo; }
  		}
  
  		public Asn1Set RecipientInfos
  		{
  			get { return recipientInfos; }
  		}
  
  		public EncryptedContentInfo AuthEncryptedContentInfo
  		{
  			get { return authEncryptedContentInfo; }
  		}
  
  		public Asn1Set AuthAttrs
  		{
  			get { return authAttrs; }
  		}
  
  		public Asn1OctetString Mac
  		{
  			get { return mac; }
  		}
  
  		public Asn1Set UnauthAttrs
  		{
  			get { return unauthAttrs; }
  		}
  
  		/**
  		 * Produce an object suitable for an Asn1OutputStream.
  		 * <pre>
  		 * AuthEnvelopedData ::= SEQUENCE {
  		 *   version CMSVersion,
  		 *   originatorInfo [0] IMPLICIT OriginatorInfo OPTIONAL,
  		 *   recipientInfos RecipientInfos,
  		 *   authEncryptedContentInfo EncryptedContentInfo,
  		 *   authAttrs [1] IMPLICIT AuthAttributes OPTIONAL,
  		 *   mac MessageAuthenticationCode,
  		 *   unauthAttrs [2] IMPLICIT UnauthAttributes OPTIONAL }
  		 * </pre>
  		 */
  	    public override Asn1Object ToAsn1Object()
  		{
  			Asn1EncodableVector v = new Asn1EncodableVector(version);
  
  			if (originatorInfo != null)
  			{
  				v.Add(new DerTaggedObject(false, 0, originatorInfo));
  			}
  
  			v.Add(recipientInfos, authEncryptedContentInfo);
  
  			// "authAttrs optionally contains the authenticated attributes."
  			if (authAttrs != null)
  			{
  				// "AuthAttributes MUST be DER encoded, even if the rest of the
  				// AuthEnvelopedData structure is BER encoded."
  				v.Add(new DerTaggedObject(false, 1, authAttrs));
  			}
  
  			v.Add(mac);
  
  			// "unauthAttrs optionally contains the unauthenticated attributes."
  			if (unauthAttrs != null)
  			{
  				v.Add(new DerTaggedObject(false, 2, unauthAttrs));
  			}
  
  
gt: 			return new BerSequence(v);