Java ElGamalParameters类代码示例

import org.bouncycastle.crypto.params.ElGamalParameters; //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.ElGamalParameters; //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.ElGamalParameters; //导入依赖的package包/类
@Override
public AsymmetricCipherKeyPairGenerator createAsymmetricCipherKeyPairGenerator(final boolean initWithDefaults) {
	final ElGamalKeyPairGenerator generator = new ElGamalKeyPairGenerator();

	if (initWithDefaults) {
		/*
		 * How certain do we want to be that the chosen primes are really primes.
		 * <p>
		 * The higher this number, the more tests are done to make sure they are primes (and not composites).
		 * <p>
		 * See: <a href="http://crypto.stackexchange.com/questions/3114/what-is-the-correct-value-for-certainty-in-rsa-key-pair-generation">What is the correct value for “certainty” in RSA key pair generation?</a>
		 * and
		 * <a href="http://crypto.stackexchange.com/questions/3126/does-a-high-exponent-compensate-for-a-low-degree-of-certainty?lq=1">Does a high exponent compensate for a low degree of certainty?</a>
		 */
		final int certainty = 12;

		final SecureRandom random = new SecureRandom();

		ElGamalParametersGenerator pGen = new ElGamalParametersGenerator();
		pGen.init(4096, certainty, random);
		ElGamalParameters elGamalParameters = pGen.generateParameters();
		generator.init(new ElGamalKeyGenerationParameters(random, elGamalParameters));
	}
	return generator;
}
 

import org.bouncycastle.crypto.params.ElGamalParameters; //导入依赖的package包/类
private ElGamalKeyGenerationParameters createElGamalKeyGenerationParameters(final CreatePgpKeyParam createPgpKeyParam) {
	/*
	 * How certain do we want to be that the chosen primes are really primes.
	 * <p>
	 * The higher this number, the more tests are done to make sure they are primes (and not composites).
	 * <p>
	 * See: <a href="http://crypto.stackexchange.com/questions/3114/what-is-the-correct-value-for-certainty-in-rsa-key-pair-generation">What is the correct value for “certainty” in RSA key pair generation?</a>
	 * and
	 * <a href="http://crypto.stackexchange.com/questions/3126/does-a-high-exponent-compensate-for-a-low-degree-of-certainty?lq=1">Does a high exponent compensate for a low degree of certainty?</a>
	 */
	final int certainty = 8; // 12 takes ages - and DSA+El-Gamal is anyway a bad idea and discouraged. Reducing this to make it bearable.

	final SecureRandom random = getSecureRandom();

	ElGamalParametersGenerator pGen = new ElGamalParametersGenerator();
	pGen.init(createPgpKeyParam.getStrength(), certainty, random);
	ElGamalParameters elGamalParameters = pGen.generateParameters();

	// Maybe we should generate our "DH safe primes" only once and store them somewhere? Or maybe we should provide a long list
	// of them in the resources? DHParametersHelper.generateSafePrimes(size, certainty, random); takes really really very long.
	// BUT BEWARE: Attacks on El Gamal can re-use expensively calculated stuff, if p (one of the "safe primes) is the same.
	// However, it is still not *so* easy. Hmmm... don't know. Security is really important here.

	return new ElGamalKeyGenerationParameters(random, elGamalParameters);
}
 

import org.bouncycastle.crypto.params.ElGamalParameters; //导入依赖的package包/类
/**
 * which generates the p and g values from the given parameters,
 * returning the ElGamalParameters object.
 * <p>
 * Note: can take a while...
 */
public ElGamalParameters generateParameters()
{
    //
    // find a safe prime p where p = 2*q + 1, where p and q are prime.
    //
    BigInteger[] safePrimes = DHParametersHelper.generateSafePrimes(size, certainty, random);

    BigInteger p = safePrimes[0];
    BigInteger q = safePrimes[1];
    BigInteger g = DHParametersHelper.selectGenerator(p, q, random);

    return new ElGamalParameters(p, g);
}
 

import org.bouncycastle.crypto.params.ElGamalParameters; //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.ElGamalParameters; //导入依赖的package包/类
protected AlgorithmParameters engineGenerateParameters()
{
    ElGamalParametersGenerator pGen = new ElGamalParametersGenerator();

    if (random != null)
    {
        pGen.init(strength, 20, random);
    }
    else
    {
        pGen.init(strength, 20, new SecureRandom());
    }

    ElGamalParameters p = pGen.generateParameters();

    AlgorithmParameters params;

    try
    {
        params = AlgorithmParameters.getInstance("ElGamal", BouncyCastleProvider.PROVIDER_NAME);
        params.init(new DHParameterSpec(p.getP(), p.getG(), l));
    }
    catch (Exception e)
    {
        throw new RuntimeException(e.getMessage());
    }

    return params;
}
 

import org.bouncycastle.crypto.params.ElGamalParameters; //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.ElGamalParameters; //导入依赖的package包/类
static public AsymmetricKeyParameter generatePrivateKeyParameter(
    PrivateKey    key)
    throws InvalidKeyException
{
    if (key instanceof ElGamalPrivateKey)
    {
        ElGamalPrivateKey    k = (ElGamalPrivateKey)key;

        return new ElGamalPrivateKeyParameters(k.getX(),
            new ElGamalParameters(k.getParams().getP(), k.getParams().getG()));
    }
                    
    throw new InvalidKeyException("can't identify ElGamal private key.");
}
 

import org.bouncycastle.crypto.params.ElGamalParameters; //导入依赖的package包/类
protected AlgorithmParameters engineGenerateParameters()
     {
         ElGamalParametersGenerator pGen = new ElGamalParametersGenerator();

if ( random != null )
{
	pGen.init(strength, 20, random);
}
else
{
	pGen.init(strength, 20, new SecureRandom());
}

         ElGamalParameters p = pGen.generateParameters();

         AlgorithmParameters params;

         try
         {
             params = AlgorithmParameters.getInstance("ElGamal", BouncyCastleProvider.PROVIDER_NAME);
             params.init(new ElGamalParameterSpec(p.getP(), p.getG()));
         }
         catch (Exception e)
         {
             throw new RuntimeException(e.getMessage());
         }

         return params;
     }
 

import org.bouncycastle.crypto.params.ElGamalParameters; //导入依赖的package包/类
protected AlgorithmParameters engineGenerateParameters()
{
    ElGamalParametersGenerator pGen = new ElGamalParametersGenerator();

    if (random != null)
    {
        pGen.init(strength, 20, random);
    }
    else
    {
        pGen.init(strength, 20, new SecureRandom());
    }

    ElGamalParameters p = pGen.generateParameters();

    AlgorithmParameters params;

    try
    {
        params = createParametersInstance("ElGamal");
        params.init(new DHParameterSpec(p.getP(), p.getG(), l));
    }
    catch (Exception e)
    {
        throw new RuntimeException(e.getMessage());
    }

    return params;
}
 

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

import org.bouncycastle.crypto.params.ElGamalParameters; //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);
}