Java Gmp.modPowSecure方法代码示例

import com.squareup.jnagmp.Gmp; //导入方法依赖的package包/类
public static BigInteger modExp(BigInteger base, BigInteger exponent, BigInteger modulus) {
    if (gmpLoaded) {
        if (exponent.signum() < 0) {
            return Gmp.modPowSecure(modInverse(base, modulus), exponent.negate(), modulus);
        } else {
            return Gmp.modPowSecure(base, exponent, modulus);
        }
    } else {
        return base.modPow(exponent, modulus);
    }
}
 

import com.squareup.jnagmp.Gmp; //导入方法依赖的package包/类
/**
 * Performs modPow: ({@code base}^{@code exponent}) mod {@code modulus}
 * 
 * This method uses the values of {@code paillier.useGMPForModPow} and {@code paillier.GMPConstantTimeMode} as they were when the class was loaded to decide
 * which implementation of modPow to invoke.
 * 
 * These values can be reloaded by invoking static method {@code ModPowAbstraction.reloadConfiguration()}
 * 
 * @return The result of modPow
 */
public static BigInteger modPow(BigInteger base, BigInteger exponent, BigInteger modulus)
{
  BigInteger result;

  if (useGMPForModPow)
  {
    if (useGMPConstantTimeMethods)
    {
      // Use GMP and use the "timing attack resistant" method
      // The timing attack resistance slows down performance and is not necessarily proven to block timing attacks.
      // Before getting concerned, please carefully consider your threat model
      // and if you really believe that you may need it
      result = Gmp.modPowSecure(base, exponent, modulus);
    }
    else
    {
      // The word "insecure" here does not imply any actual, direct insecurity.
      // It denotes that this function runs as fast as possible without trying to
      // counteract timing attacks. This is probably what you want unless you have a
      // compelling reason why you believe that this environment is safe enough to house
      // your keys but doesn't protect you from another entity on the machine watching
      // how long the program runs.
      result = Gmp.modPowInsecure(base, exponent, modulus);
    }
  }
  else
  {
    // If GMP isn't used, BigInteger's built-in modPow is used.
    // This is significantly slower but has the virtue of working everywhere.
    result = base.modPow(exponent, modulus);
  }

  return result;
}
 

import com.squareup.jnagmp.Gmp; //导入方法依赖的package包/类
/**
 * computes a modular exponentiation. It will call the GMP library, if available on this system.
 * If GMP is available, it will use 'mpz_powm_sec' which is side channel attack resistant.
 * Use this function if you want to protect the exponent from side channel attacks.
 * @param base of the modular exponentiation
 * @param exponent of the exponentiation
 * @param modulus
 * @return (base ^ exponent) mod modulus
 */
public static BigInteger modPowSecure(BigInteger base, BigInteger exponent, BigInteger modulus) {
  if (USE_GMP) {
    return exponent.signum() < 0 // Gmp library can't handle negative exponents
        ? modInverse(Gmp.modPowSecure(base, exponent.negate(), modulus), modulus)
        : Gmp.modPowSecure(base, exponent, modulus);
  } else {
    logger.log(Level.WARNING,
        "Gmp library is not available. Falling back to native Java for modPow. This does not "
        + "provide protection against timing attacks!");
    return base.modPow(exponent, modulus);
  }
}
 

import com.squareup.jnagmp.Gmp; //导入方法依赖的package包/类
/**
 * Process a single block using the basic RSA algorithm.
 *
 * @param in the input array.
 * @param inOff the offset into the input buffer where the data starts.
 * @param inLen the length of the data to be processed.
 * @return the result of the RSA process.
 * @exception DataLengthException the input block is too large.
 */
@Override
public byte[] processBlock(final byte[] in, final int inOff, final int inLen) {
    if (key == null) {
        throw new IllegalStateException("RSA engine not initialised");
    }

    BigInteger input = core.convertInput(in, inOff, inLen);

    BigInteger result;
    if (key instanceof RSAPrivateCrtKeyParameters) {
        RSAPrivateCrtKeyParameters k = (RSAPrivateCrtKeyParameters)key;

        BigInteger e = k.getPublicExponent();
        // can't do blinding without a public exponent
        if (e != null) {
            BigInteger m = k.getModulus();
            BigInteger r = BigIntegers.createRandomInRange(ONE, m.subtract(ONE), random);

            // This is a modification to use the GMP native library method
            BigInteger blindedModPow = Gmp.modPowSecure(r, e, m);

            BigInteger blindedInput = blindedModPow.multiply(input).mod(m);
            BigInteger blindedResult = core.processBlock(blindedInput);

            // This is a modification to use the GMP native library method
            BigInteger rInv = Gmp.modInverse(r, m);

            result = blindedResult.multiply(rInv).mod(m);
            // defence against Arjen Lenstra’s CRT attack
            // This is a modification to use the GMP native library method
            if (!input.equals(Gmp.modPowInsecure(result, e, m))) {
                throw new IllegalStateException("RSA engine faulty decryption/signing detected");
            }
        } else {
            result = core.processBlock(input);
        }
    } else {
        result = core.processBlock(input);
    }

    return core.convertOutput(result);
}