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package org.spongycastle.openpgp.operator.jcajce;
import java.io.IOException;
import java.math.BigInteger;
import java.security.InvalidKeyException;
import java.security.Key;
import java.security.Provider;
import java.security.SecureRandom;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.spec.SecretKeySpec;
import org.spongycastle.asn1.nist.NISTNamedCurves;
import org.spongycastle.asn1.x9.X9ECParameters;
import org.spongycastle.bcpg.ECDHPublicBCPGKey;
import org.spongycastle.bcpg.MPInteger;
import org.spongycastle.bcpg.PublicKeyAlgorithmTags;
import org.spongycastle.crypto.EphemeralKeyPair;
import org.spongycastle.crypto.KeyEncoder;
import org.spongycastle.crypto.generators.ECKeyPairGenerator;
import org.spongycastle.crypto.generators.EphemeralKeyPairGenerator;
import org.spongycastle.crypto.params.AsymmetricKeyParameter;
import org.spongycastle.crypto.params.ECDomainParameters;
import org.spongycastle.crypto.params.ECKeyGenerationParameters;
import org.spongycastle.crypto.params.ECPrivateKeyParameters;
import org.spongycastle.crypto.params.ECPublicKeyParameters;
import org.spongycastle.jcajce.util.DefaultJcaJceHelper;
import org.spongycastle.jcajce.util.NamedJcaJceHelper;
import org.spongycastle.jcajce.util.ProviderJcaJceHelper;
import org.spongycastle.math.ec.ECPoint;
import org.spongycastle.openpgp.PGPException;
import org.spongycastle.openpgp.PGPPublicKey;
import org.spongycastle.openpgp.operator.PGPPad;
import org.spongycastle.openpgp.operator.PublicKeyKeyEncryptionMethodGenerator;
import org.spongycastle.openpgp.operator.RFC6637KDFCalculator;
public class JcePublicKeyKeyEncryptionMethodGenerator
extends PublicKeyKeyEncryptionMethodGenerator
{
private OperatorHelper helper = new OperatorHelper(new DefaultJcaJceHelper());
private SecureRandom random;
private JcaPGPKeyConverter keyConverter = new JcaPGPKeyConverter();
private JcaPGPDigestCalculatorProviderBuilder digestCalculatorProviderBuilder = new JcaPGPDigestCalculatorProviderBuilder();
/**
* Create a public key encryption method generator with the method to be based on the passed in key.
*
* @param key the public key to use for encryption.
*/
public JcePublicKeyKeyEncryptionMethodGenerator(PGPPublicKey key)
{
super(key);
}
public JcePublicKeyKeyEncryptionMethodGenerator setProvider(Provider provider)
{
this.helper = new OperatorHelper(new ProviderJcaJceHelper(provider));
keyConverter.setProvider(provider);
return this;
}
public JcePublicKeyKeyEncryptionMethodGenerator setProvider(String providerName)
{
this.helper = new OperatorHelper(new NamedJcaJceHelper(providerName));
keyConverter.setProvider(providerName);
return this;
}
/**
* Provide a user defined source of randomness.
*
* @param random the secure random to be used.
* @return the current generator.
*/
public JcePublicKeyKeyEncryptionMethodGenerator setSecureRandom(SecureRandom random)
{
this.random = random;
return this;
}
protected byte[] encryptSessionInfo(PGPPublicKey pubKey, byte[] sessionInfo)
throws PGPException
{
try
{
if (pubKey.getAlgorithm() == PublicKeyAlgorithmTags.ECDH)
{
ECDHPublicBCPGKey ecKey = (ECDHPublicBCPGKey)pubKey.getPublicKeyPacket().getKey();
X9ECParameters x9Params = NISTNamedCurves.getByOID(ecKey.getCurveOID());
ECDomainParameters ecParams = new ECDomainParameters(x9Params.getCurve(), x9Params.getG(), x9Params.getN());
// Generate the ephemeral key pair
ECKeyPairGenerator gen = new ECKeyPairGenerator();
gen.init(new ECKeyGenerationParameters(ecParams, random));
EphemeralKeyPairGenerator kGen = new EphemeralKeyPairGenerator(gen, new KeyEncoder()
{
public byte[] getEncoded(AsymmetricKeyParameter keyParameter)
{
return ((ECPublicKeyParameters)keyParameter).getQ().getEncoded(false);
}
});
EphemeralKeyPair ephKp = kGen.generate();
ECPrivateKeyParameters ephPriv = (ECPrivateKeyParameters)ephKp.getKeyPair().getPrivate();
ECPoint S = ecKey.getPoint().multiply(ephPriv.getD()).normalize();
RFC6637KDFCalculator rfc6637KDFCalculator = new RFC6637KDFCalculator(digestCalculatorProviderBuilder.build().get(ecKey.getHashAlgorithm()), ecKey.getSymmetricKeyAlgorithm());
Key key = new SecretKeySpec(rfc6637KDFCalculator.createKey(ecKey.getCurveOID(), S, pubKey.getFingerprint()), "AESWrap");
Cipher c = helper.createKeyWrapper(ecKey.getSymmetricKeyAlgorithm());
c.init(Cipher.WRAP_MODE, key, random);
byte[] paddedSessionData = PGPPad.padSessionData(sessionInfo);
byte[] C = c.wrap(new SecretKeySpec(paddedSessionData, PGPUtil.getSymmetricCipherName(sessionInfo[0])));
byte[] VB = new MPInteger(new BigInteger(1, ephKp.getEncodedPublicKey())).getEncoded();
byte[] rv = new byte[VB.length + 1 + C.length];
System.arraycopy(VB, 0, rv, 0, VB.length);
rv[VB.length] = (byte)C.length;
System.arraycopy(C, 0, rv, VB.length + 1, C.length);
return rv;
}
else
{
Cipher c = helper.createPublicKeyCipher(pubKey.getAlgorithm());
Key key = keyConverter.getPublicKey(pubKey);
c.init(Cipher.ENCRYPT_MODE, key, random);
return c.doFinal(sessionInfo);
}
}
catch (IllegalBlockSizeException e)
{
throw new PGPException("illegal block size: " + e.getMessage(), e);
}
catch (BadPaddingException e)
{
throw new PGPException("bad padding: " + e.getMessage(), e);
}
catch (InvalidKeyException e)
{
throw new PGPException("key invalid: " + e.getMessage(), e);
}
catch (IOException e)
{
throw new PGPException("unable to encode MPI: " + e.getMessage(), e);
}
}
}
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