JcePublicKeyKeyEncryptionMethodGenerator.java

package org.spongycastle.openpgp.operator.jcajce;

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 org.spongycastle.jcajce.DefaultJcaJceHelper;
import org.spongycastle.jcajce.NamedJcaJceHelper;
import org.spongycastle.jcajce.ProviderJcaJceHelper;
import org.spongycastle.openpgp.PGPException;
import org.spongycastle.openpgp.PGPPublicKey;
import org.spongycastle.openpgp.operator.PublicKeyKeyEncryptionMethodGenerator;

public class JcePublicKeyKeyEncryptionMethodGenerator
    extends PublicKeyKeyEncryptionMethodGenerator
{
    private OperatorHelper helper = new OperatorHelper(new DefaultJcaJceHelper());
    private SecureRandom random;
    private JcaPGPKeyConverter keyConverter = new JcaPGPKeyConverter();

    /**
     * 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
        {
            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);
        }
    }
}