KekRecipientInfoGenerator
using Org.BouncyCastle.Asn1;
using Org.BouncyCastle.Asn1.Cms;
using Org.BouncyCastle.Asn1.Kisa;
using Org.BouncyCastle.Asn1.Nist;
using Org.BouncyCastle.Asn1.Ntt;
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;
using System;
namespace Org.BouncyCastle.Cms
{
internal class KekRecipientInfoGenerator : RecipientInfoGenerator
{
private KeyParameter keyEncryptionKey;
private string keyEncryptionKeyOID;
private KekIdentifier kekIdentifier;
private AlgorithmIdentifier keyEncryptionAlgorithm;
internal KekIdentifier KekIdentifier {
set {
kekIdentifier = value;
}
}
internal KeyParameter KeyEncryptionKey {
set {
keyEncryptionKey = value;
keyEncryptionAlgorithm = DetermineKeyEncAlg(keyEncryptionKeyOID, keyEncryptionKey);
}
}
internal string KeyEncryptionKeyOID {
set {
keyEncryptionKeyOID = value;
}
}
internal KekRecipientInfoGenerator()
{
}
public RecipientInfo Generate(KeyParameter contentEncryptionKey, SecureRandom random)
{
byte[] key = contentEncryptionKey.GetKey();
IWrapper wrapper = WrapperUtilities.GetWrapper(keyEncryptionAlgorithm.Algorithm.Id);
wrapper.Init(true, new ParametersWithRandom(keyEncryptionKey, random));
Asn1OctetString encryptedKey = new DerOctetString(wrapper.Wrap(key, 0, key.Length));
return new RecipientInfo(new KekRecipientInfo(kekIdentifier, keyEncryptionAlgorithm, encryptedKey));
}
private static AlgorithmIdentifier DetermineKeyEncAlg(string algorithm, KeyParameter key)
{
if (Platform.StartsWith(algorithm, "DES"))
return new AlgorithmIdentifier(PkcsObjectIdentifiers.IdAlgCms3DesWrap, DerNull.Instance);
if (Platform.StartsWith(algorithm, "RC2"))
return new AlgorithmIdentifier(PkcsObjectIdentifiers.IdAlgCmsRC2Wrap, new DerInteger(58));
if (Platform.StartsWith(algorithm, "AES")) {
DerObjectIdentifier algorithm2;
switch (key.KeyLength * 8) {
case 128:
algorithm2 = NistObjectIdentifiers.IdAes128Wrap;
break;
case 192:
algorithm2 = NistObjectIdentifiers.IdAes192Wrap;
break;
case 256:
algorithm2 = NistObjectIdentifiers.IdAes256Wrap;
break;
default:
throw new ArgumentException("illegal keysize in AES");
}
return new AlgorithmIdentifier(algorithm2);
}
if (Platform.StartsWith(algorithm, "SEED"))
return new AlgorithmIdentifier(KisaObjectIdentifiers.IdNpkiAppCmsSeedWrap);
if (Platform.StartsWith(algorithm, "CAMELLIA")) {
DerObjectIdentifier algorithm3;
switch (key.KeyLength * 8) {
case 128:
algorithm3 = NttObjectIdentifiers.IdCamellia128Wrap;
break;
case 192:
algorithm3 = NttObjectIdentifiers.IdCamellia192Wrap;
break;
case 256:
algorithm3 = NttObjectIdentifiers.IdCamellia256Wrap;
break;
default:
throw new ArgumentException("illegal keysize in Camellia");
}
return new AlgorithmIdentifier(algorithm3);
}
throw new ArgumentException("unknown algorithm");
}
}
}