import org.bouncycastle.crypto.params.ElGamalPublicKeyParameters; //导入依赖的package包/类
public AsymmetricCipherKeyPair generateKeyPair()
  {
      BigInteger           p, g, x, y;
      int                  qLength = param.getStrength() - 1;
      ElGamalParameters    elParams = param.getParameters();

      p = elParams.getP();
      g = elParams.getG();
  
      //
      // calculate the private key
      //
x = new BigInteger(qLength, param.getRandom());

      //
      // calculate the public key.
      //
      y = g.modPow(x, p);

      return new AsymmetricCipherKeyPair(
              new ElGamalPublicKeyParameters(y, elParams),
              new ElGamalPrivateKeyParameters(x, elParams));
  }
 

import org.bouncycastle.crypto.params.ElGamalPublicKeyParameters; //导入依赖的package包/类
private void testInvalidP()
{
    ElGamalParameters               dhParams = new ElGamalParameters(pPgpBogusPSamp, gPgpBogusPSamp, lPgpBogusPSamp);
    ElGamalPublicKeyParameters      pu = new ElGamalPublicKeyParameters(yPgpBogusPSamp, dhParams);
    ElGamalPrivateKeyParameters     pv = new ElGamalPrivateKeyParameters(xPgpBogusPSamp, dhParams);

    ElGamalEngine    e = new ElGamalEngine();

    e.init(true, pu);

    byte[]  message = Hex.decode("5468697320697320612074657374");

    byte[]  pText = message;
    byte[]  cText = e.processBlock(pText, 0, pText.length);

    e.init(false, pv);

    pText = e.processBlock(cText, 0, cText.length);

    if (Arrays.areEqual(message, pText))
    {
        fail("invalid test failed");
    }
}
 

import org.bouncycastle.crypto.params.ElGamalPublicKeyParameters; //导入依赖的package包/类
public AsymmetricCipherKeyPair generateKeyPair()
{
    DHKeyGeneratorHelper helper = DHKeyGeneratorHelper.INSTANCE;
    ElGamalParameters egp = param.getParameters();
    DHParameters dhp = new DHParameters(egp.getP(), egp.getG(), null, egp.getL());  

    BigInteger x = helper.calculatePrivate(dhp, param.getRandom()); 
    BigInteger y = helper.calculatePublic(dhp, x);

    return new AsymmetricCipherKeyPair(
        new ElGamalPublicKeyParameters(y, egp),
        new ElGamalPrivateKeyParameters(x, egp));
}
 

import org.bouncycastle.crypto.params.ElGamalPublicKeyParameters; //导入依赖的package包/类
static public AsymmetricKeyParameter generatePublicKeyParameter(
    PublicKey    key)
    throws InvalidKeyException
{
    if (key instanceof ElGamalPublicKey)
    {
        ElGamalPublicKey    k = (ElGamalPublicKey)key;

        return new ElGamalPublicKeyParameters(k.getY(),
            new ElGamalParameters(k.getParams().getP(), k.getParams().getG()));
    }

    throw new InvalidKeyException("can't identify ElGamal public key.");
}
 

import org.bouncycastle.crypto.params.ElGamalPublicKeyParameters; //导入依赖的package包/类
@Override
public byte[] encryptWithPublicKey(byte[] data) {
	ElGamalParameters params = new ElGamalParameters(keys.getP(), keys.getG());
	ElGamalPublicKeyParameters pubKey = new ElGamalPublicKeyParameters(keys.getPublicKey(), params);
	
	ElGamalEngine e = new ElGamalEngine();
	e.init(true, pubKey);
       return e.processBlock(data, 0, data.length) ;
}
 

import org.bouncycastle.crypto.params.ElGamalPublicKeyParameters; //导入依赖的package包/类
public ElGamalEncrypt encryptForContract(byte[] data) {
	ElGamalParameters params = new ElGamalParameters(keys.getP(), keys.getG());
	ElGamalPublicKeyParameters pubKey = new ElGamalPublicKeyParameters(keys.getPublicKey(), params);
	
	ElGamalEngine e = new ElGamalEngine();
	e.init(true, pubKey);
	byte[] m = e.processBlock(data, 0, data.length);
	BigInteger k = e.getK();
       BigInteger u = keys.getG().modPow(k,keys.getP());
       BigInteger v = (keys.getPublicKey().modPow(e.getK(), keys.getP()).multiply(new BigInteger(data)));
       return new ElGamalEncrypt (u,v,k, m);
}
 

import org.bouncycastle.crypto.params.ElGamalPublicKeyParameters; //导入依赖的package包/类
/**
 * This method is used to generate Public Key and Private Key
 * @param params
 */
private void GenerateKeys(ElGamalParameters params, String password){
	ElGamalKeyGenerationParameters elGP = new ElGamalKeyGenerationParameters(random,params);
	ElGamalKeyPairGenerator KeyPair = new ElGamalKeyPairGenerator();
	KeyPair.init(elGP);
	AsymmetricCipherKeyPair cipher1 = KeyPair.generateKeyPair();
	publicKey = ((ElGamalPublicKeyParameters) cipher1.getPublic()).getY();
	privateKey = ((ElGamalPrivateKeyParameters)cipher1.getPrivate()).getX();
	wellGenerated = true;
	encryptPrivateKey(password);
}
 

import org.bouncycastle.crypto.params.ElGamalPublicKeyParameters; //导入依赖的package包/类
JCEElGamalPublicKey(
    ElGamalPublicKeyParameters  params)
{
    this.y = params.getY();
    this.elSpec = new ElGamalParameterSpec(params.getParameters().getP(), params.getParameters().getG());
}
 

import org.bouncycastle.crypto.params.ElGamalPublicKeyParameters; //导入依赖的package包/类
BCElGamalPublicKey(
    ElGamalPublicKeyParameters params)
{
    this.y = params.getY();
    this.elSpec = new ElGamalParameterSpec(params.getParameters().getP(), params.getParameters().getG());
}
 

import org.bouncycastle.crypto.params.ElGamalPublicKeyParameters; //导入依赖的package包/类
/**
 * this test is can take quiet a while
 *
 * @param size size of key in bits.
 */
private void testGeneration(
    int         size)
{
    ElGamalParametersGenerator       pGen = new ElGamalParametersGenerator();

    pGen.init(size, 10, new SecureRandom());

    ElGamalParameters                elParams = pGen.generateParameters();

    if (elParams.getL() != 0)
    {
        fail("ElGamalParametersGenerator failed to set L to 0 in generated ElGamalParameters");
    }

    ElGamalKeyGenerationParameters   params = new ElGamalKeyGenerationParameters(new SecureRandom(), elParams);

    ElGamalKeyPairGenerator          kpGen = new ElGamalKeyPairGenerator();

    kpGen.init(params);

    //
    // generate first pair
    //
    AsymmetricCipherKeyPair         pair = kpGen.generateKeyPair();

    ElGamalPublicKeyParameters      pu = (ElGamalPublicKeyParameters)pair.getPublic();
    ElGamalPrivateKeyParameters     pv = (ElGamalPrivateKeyParameters)pair.getPrivate();

    ElGamalEngine    e = new ElGamalEngine();

    e.init(true, new ParametersWithRandom(pu, new SecureRandom()));

    byte[]  message = Hex.decode("5468697320697320612074657374");

    byte[]  pText = message;
    byte[]  cText = e.processBlock(pText, 0, pText.length);

    e.init(false, pv);

    pText = e.processBlock(cText, 0, cText.length);

    if (!Arrays.areEqual(message, pText))
    {
        fail("generation test failed");
    }
}