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using System;
using Org.BouncyCastle.Asn1;
using Org.BouncyCastle.Asn1.Cms;
using Org.BouncyCastle.Asn1.Pkcs;
using Org.BouncyCastle.Asn1.X509;
using Org.BouncyCastle.Crypto;
using Org.BouncyCastle.Crypto.Parameters;
using Org.BouncyCastle.Security;
using Org.BouncyCastle.Utilities;
namespace Org.BouncyCastle.Cms
{
internal class PasswordRecipientInfoGenerator
: RecipientInfoGenerator
{
private AlgorithmIdentifier keyDerivationAlgorithm;
private KeyParameter keyEncryptionKey;
// TODO Can get this from keyEncryptionKey?
private string keyEncryptionKeyOID;
internal PasswordRecipientInfoGenerator()
{
}
internal AlgorithmIdentifier KeyDerivationAlgorithm
{
set { this.keyDerivationAlgorithm = value; }
}
internal KeyParameter KeyEncryptionKey
{
set { this.keyEncryptionKey = value; }
}
internal string KeyEncryptionKeyOID
{
set { this.keyEncryptionKeyOID = value; }
}
public RecipientInfo Generate(KeyParameter contentEncryptionKey, SecureRandom random)
{
byte[] keyBytes = contentEncryptionKey.GetKey();
string rfc3211WrapperName = CmsEnvelopedHelper.GetRfc3211WrapperName(keyEncryptionKeyOID);
IWrapper keyWrapper = WrapperUtilities.GetWrapper(rfc3211WrapperName);
// Note: In Java build, the IV is automatically generated in JCE layer
int ivLength = Platform.StartsWithIgnoreCase(rfc3211WrapperName, "DES") ? 8 : 16;
#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
var parametersWithIV = ParametersWithIV.Create(keyEncryptionKey, ivLength, random,
(bytes, random) => random.NextBytes(bytes));
#else
byte[] iv = new byte[ivLength];
random.NextBytes(iv);
var parametersWithIV = new ParametersWithIV(keyEncryptionKey, iv);
#endif
keyWrapper.Init(true, new ParametersWithRandom(parametersWithIV, random));
Asn1OctetString encryptedKey = new DerOctetString(
keyWrapper.Wrap(keyBytes, 0, keyBytes.Length));
DerSequence seq = new DerSequence(
new DerObjectIdentifier(keyEncryptionKeyOID),
#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
new DerOctetString(parametersWithIV.IV)
#else
new DerOctetString(iv)
#endif
);
AlgorithmIdentifier keyEncryptionAlgorithm = new AlgorithmIdentifier(
PkcsObjectIdentifiers.IdAlgPwriKek, seq);
return new RecipientInfo(new PasswordRecipientInfo(
keyDerivationAlgorithm, keyEncryptionAlgorithm, encryptedKey));
}
}
}
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