138 lines
3.8 KiB
C#
138 lines
3.8 KiB
C#
using System;
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using System.IO;
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using Org.BouncyCastle.Asn1;
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using Org.BouncyCastle.Asn1.Nist;
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using Org.BouncyCastle.Asn1.Pkcs;
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using Org.BouncyCastle.Asn1.X509;
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using Org.BouncyCastle.Crypto;
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using Org.BouncyCastle.Crypto.IO;
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using Org.BouncyCastle.Crypto.Parameters;
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using Org.BouncyCastle.Security;
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using Org.BouncyCastle.Utilities.Collections;
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namespace Org.BouncyCastle.Cms
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{
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public abstract class RecipientInformation
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{
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internal RecipientID _rid = new RecipientID();
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internal AlgorithmIdentifier _encAlg;
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internal AlgorithmIdentifier _keyEncAlg;
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internal Stream _data;
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internal RecipientInformation(
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AlgorithmIdentifier encAlg,
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AlgorithmIdentifier keyEncAlg,
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Stream data)
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{
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if (!data.CanRead)
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throw new ArgumentException("Expected input stream", "data");
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this._encAlg = encAlg;
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this._keyEncAlg = keyEncAlg;
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this._data = data;
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}
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public RecipientID RecipientID
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{
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get { return _rid; }
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}
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public AlgorithmIdentifier KeyEncryptionAlgorithmID
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{
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get { return _keyEncAlg; }
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}
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/**
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* return the object identifier for the key encryption algorithm.
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* @return OID for key encryption algorithm.
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*/
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public string KeyEncryptionAlgOid
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{
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get { return _keyEncAlg.ObjectID.Id; }
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}
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/**
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* return the ASN.1 encoded key encryption algorithm parameters, or null if
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* there aren't any.
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* @return ASN.1 encoding of key encryption algorithm parameters.
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*/
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public Asn1Object KeyEncryptionAlgParams
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{
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get
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{
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Asn1Encodable ae = _keyEncAlg.Parameters;
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return ae == null ? null : ae.ToAsn1Object();
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}
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}
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internal CmsTypedStream GetContentFromSessionKey(
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KeyParameter sKey)
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{
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try
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{
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IBufferedCipher cipher = CipherUtilities.GetCipher(_encAlg.ObjectID);
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Asn1Encodable asn1Enc = _encAlg.Parameters;
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Asn1Object asn1Params = asn1Enc == null ? null : asn1Enc.ToAsn1Object();
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ICipherParameters cipherParameters = sKey;
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if (asn1Params != null && !(asn1Params is Asn1Null))
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{
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cipherParameters = ParameterUtilities.GetCipherParameters(
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_encAlg.ObjectID, cipherParameters, asn1Params);
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}
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else
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{
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string alg = _encAlg.ObjectID.Id;
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if (alg.Equals(CmsEnvelopedDataGenerator.DesEde3Cbc)
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|| alg.Equals(CmsEnvelopedDataGenerator.IdeaCbc)
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|| alg.Equals(CmsEnvelopedDataGenerator.Cast5Cbc))
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{
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cipherParameters = new ParametersWithIV(cipherParameters, new byte[8]);
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}
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}
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cipher.Init(false, cipherParameters);
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return new CmsTypedStream(new CipherStream(_data, cipher, null));
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}
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catch (SecurityUtilityException e)
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{
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throw new CmsException("couldn't create cipher.", e);
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}
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catch (InvalidKeyException e)
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{
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throw new CmsException("key invalid in message.", e);
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}
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catch (IOException e)
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{
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throw new CmsException("error decoding algorithm parameters.", e);
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}
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}
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public byte[] GetContent(
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ICipherParameters key)
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{
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try
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{
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if (_data is MemoryStream)
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{
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// _data.Reset();
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_data.Seek(0L, SeekOrigin.Begin);
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}
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return CmsUtilities.StreamToByteArray(GetContentStream(key).ContentStream);
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}
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catch (IOException e)
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{
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throw new Exception("unable to parse internal stream: " + e);
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}
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}
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public abstract CmsTypedStream GetContentStream(ICipherParameters key);
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}
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}
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