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using System;
using System.IO;
using Org.BouncyCastle.Asn1;
using Org.BouncyCastle.Asn1.Cms;
using Org.BouncyCastle.Asn1.X509;
using Org.BouncyCastle.Crypto;
using Org.BouncyCastle.Crypto.Parameters;
using Org.BouncyCastle.Security;
namespace Org.BouncyCastle.Cms
{
/**
* the RecipientInfo class for a recipient who has been sent a message
* encrypted using a password.
*/
public class PasswordRecipientInformation
: RecipientInformation
{
private readonly PasswordRecipientInfo info;
internal PasswordRecipientInformation(
PasswordRecipientInfo info,
CmsSecureReadable secureReadable)
: base(info.KeyEncryptionAlgorithm, secureReadable)
{
this.info = info;
this.rid = new RecipientID();
}
/**
* return the object identifier for the key derivation algorithm, or null
* if there is none present.
*
* @return OID for key derivation algorithm, if present.
*/
public virtual AlgorithmIdentifier KeyDerivationAlgorithm
{
get { return info.KeyDerivationAlgorithm; }
}
/**
* decrypt the content and return an input stream.
*/
public override CmsTypedStream GetContentStream(
ICipherParameters key)
{
try
{
AlgorithmIdentifier kekAlg = AlgorithmIdentifier.GetInstance(info.KeyEncryptionAlgorithm);
Asn1Sequence kekAlgParams = (Asn1Sequence)kekAlg.Parameters;
byte[] encryptedKey = info.EncryptedKey.GetOctets();
string kekAlgName = DerObjectIdentifier.GetInstance(kekAlgParams[0]).Id;
string cName = CmsEnvelopedHelper.GetRfc3211WrapperName(kekAlgName);
IWrapper keyWrapper = WrapperUtilities.GetWrapper(cName);
var iv = Asn1OctetString.GetInstance(kekAlgParams[1]);
ICipherParameters parameters = ((CmsPbeKey)key).GetEncoded(kekAlgName);
#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
parameters = new ParametersWithIV(parameters, iv.GetOctetsSpan());
#else
parameters = new ParametersWithIV(parameters, iv.GetOctets());
#endif
keyWrapper.Init(false, parameters);
KeyParameter sKey = ParameterUtilities.CreateKeyParameter(
GetContentAlgorithmName(), 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);
}
}
}
}
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