Java BigInteger.setBit方法代码示例

import java.math.BigInteger; //导入方法依赖的package包/类
/**
 * Returns the value of this {@code UnsignedLong} as a {@link BigInteger}.
 */
public BigInteger bigIntegerValue() {
  BigInteger bigInt = BigInteger.valueOf(value & UNSIGNED_MASK);
  if (value < 0) {
    bigInt = bigInt.setBit(Long.SIZE - 1);
  }
  return bigInt;
}
 

import java.math.BigInteger; //导入方法依赖的package包/类
private BigInteger getMaskedAddress(boolean one) {
    BigInteger numAddress = netAddress;
    int numBits;
    if (isV4) {
        numBits = 32 - networkMask;
    } else {
        numBits = 128 - networkMask;
    }
    for (int i = 0; i < numBits; i++) {
        if (one) numAddress = numAddress.setBit(i);
        else numAddress = numAddress.clearBit(i);
    }
    return numAddress;
}
 

import java.math.BigInteger; //导入方法依赖的package包/类
static String Encode(long plain, final String prefix) {

			BigInteger id = BigInteger.valueOf(plain);
			if (plain < 0) {
				id = id.add(Format.two64);
			}

			BigInteger chs = BigInteger.ZERO;
			BigInteger andVal = BigInteger.valueOf(0x3FF);
			BigInteger tmp = id;
			while (tmp.compareTo(BigInteger.ZERO) > 0) {
				chs = chs.xor(tmp.and(andVal));
				tmp = tmp.shiftRight(10);
			}
			id = id.or(chs.shiftLeft(64));
			id = id.setBit(74);

			StringBuilder idStr = new StringBuilder(prefix);
			andVal = BigInteger.valueOf(0x1F);

			for (int i = 0; i < 15; i++) {
				if ((i % 5) == 0) {
					idStr.append('-');
				}

				idStr.append(alphabet.charAt(id.and(andVal).intValue()));
				id = id.shiftRight(5);
			}

			return idStr.toString();
		}
 

import java.math.BigInteger; //导入方法依赖的package包/类
private static BigInteger convertHashToBigInt(byte[] largeHash, int bitLength) {
    // set first bit to 1. This ensures, that the BigInteger (in the next step) has the correct bitlength.
    largeHash[0] |= 0x80;

    BigInteger fdh = new BigInteger(1, largeHash);

    //cut the hash to the same size as the public key
    fdh = fdh.shiftRight((largeHash.length * 8) - bitLength);

    // set last bit to 1 to ensure that the hash is odd. (Add 1 if the hash is even)
    return fdh.setBit(0);
}
 

import java.math.BigInteger; //导入方法依赖的package包/类
private static void testValueOfMulPow52(long value, int p5, int p2) throws Exception {
    BigInteger bi = BigInteger.valueOf(value & ~LONG_SIGN_MASK);
    if (value < 0) {
        bi = bi.setBit(63);
    }
    check(biPow52(p5, p2).multiply(bi), FDBigInteger.valueOfMulPow52(value, p5, p2),
            "valueOfMulPow52(" + Long.toHexString(value) + "." + p5 + "," + p2 + ")");
}
 

import java.math.BigInteger; //导入方法依赖的package包/类
/**
 * 利用BigInteger对权限进行2的权的和计算
 *
 * @param rights
 *            int型权限编码数组
 * @return 2的权的和
 */
public static BigInteger sumRights(int[] rights) {
    BigInteger num = new BigInteger("0");
    for (int i = 0; i < rights.length; i++) {
        num = num.setBit(rights[i]);
    }
    return num;
}
 

import java.math.BigInteger; //导入方法依赖的package包/类
private ECPoint calculateMqvAgreement(
        ECDomainParameters      parameters,
        ECPrivateKeyParameters  d1U,
        ECPrivateKeyParameters  d2U,
        ECPublicKeyParameters   Q2U,
        ECPublicKeyParameters   Q1V,
        ECPublicKeyParameters   Q2V)
    {
        BigInteger n = parameters.getN();
        int e = (n.bitLength() + 1) / 2;
        BigInteger powE = ECConstants.ONE.shiftLeft(e);

        // The Q2U public key is optional
        ECPoint q;
        if (Q2U == null)
        {
            q = parameters.getG().multiply(d2U.getD());
        }
        else
        {
            q = Q2U.getQ();
        }

        BigInteger x = q.getX().toBigInteger();
        BigInteger xBar = x.mod(powE);
        BigInteger Q2UBar = xBar.setBit(e);
        BigInteger s = d1U.getD().multiply(Q2UBar).mod(n).add(d2U.getD()).mod(n);

        BigInteger xPrime = Q2V.getQ().getX().toBigInteger();
        BigInteger xPrimeBar = xPrime.mod(powE);
        BigInteger Q2VBar = xPrimeBar.setBit(e);

        BigInteger hs = parameters.getH().multiply(s).mod(n);

//        ECPoint p = Q1V.getQ().multiply(Q2VBar).add(Q2V.getQ()).multiply(hs);
        ECPoint p = ECAlgorithms.sumOfTwoMultiplies(
            Q1V.getQ(), Q2VBar.multiply(hs).mod(n), Q2V.getQ(), hs);

        if (p.isInfinity())
        {
            throw new IllegalStateException("Infinity is not a valid agreement value for MQV");
        }

        return p;
    }