Java Code Examples for java.math.BigInteger#mod()

public static String encodeRipple(byte[] input) {
	BigInteger bi = new BigInteger(1, input);
	StringBuilder s = new StringBuilder();
	while (bi.compareTo(BASE) >= 0) {
		BigInteger mod = bi.mod(BASE);
		s.insert(0, DEFAULT_ALPHABET[mod.intValue()]);
		bi = bi.subtract(mod).divide(BASE);
	}
	s.insert(0, DEFAULT_ALPHABET[bi.intValue()]);
	for (byte anInput : input) {
		if (anInput == 0) {
			s.insert(0, DEFAULT_ALPHABET[0]);
		} else {
			break;
		}
	}
	return s.toString();
}
 

/**
 * Multiplication (m*a) modulo N, with m often small and <code>a < N</code>.
 * @param m
 * @param a
 * @return (m*a) mod N
 */
private BigInteger mulModN(BigInteger m, BigInteger a) {
	if (m.bitLength()<3) { // 0, 1, 10, 11
		switch (m.intValue()) {
		case 0: return I_0;
		case 1: return a;
		case 2: {
			BigInteger two_a = a.shiftLeft(1); // faster than 2*a or a+a
       		return two_a.compareTo(N)<0 ? two_a : two_a.subtract(N);
		}
		case 3: {
			BigInteger ma_modN = a.shiftLeft(1).add(a); // < 3*N
       		if (ma_modN.compareTo(N)<0) return ma_modN;
       		ma_modN = ma_modN.subtract(N); // < 2*N
       		return ma_modN.compareTo(N)<0 ? ma_modN : ma_modN.subtract(N);
		}
		}
		// adding case 4 does not help because then bitLength() does not fit exactly
	}
	BigInteger product = m.multiply(a);
	return product.compareTo(N)<0 ? product : product.mod(N);
}
 

/**
 * 签名
 *
 * @param M       签名信息
 * @param IDA     签名方唯一标识
 * @param keyPair 签名方密钥对
 * @return 签名
 */
public Signature sign(String M, String IDA, SM2KeyPair keyPair) {
    byte[] ZA = ZA(IDA, keyPair.getPublicKey());
    byte[] M_ = join(ZA, M.getBytes());
    BigInteger e = new BigInteger(1, sm3hash(M_));
    // BigInteger k = new BigInteger(
    // "6CB28D99 385C175C 94F94E93 4817663F C176D925 DD72B727 260DBAAE
    // 1FB2F96F".replace(" ", ""), 16);
    BigInteger k;
    BigInteger r;
    do {
        k = random(n);
        ECPoint p1 = G.multiply(k).normalize();
        BigInteger x1 = p1.getXCoord().toBigInteger();
        r = e.add(x1);
        r = r.mod(n);
    } while (r.equals(BigInteger.ZERO) || r.add(k).equals(n));

    BigInteger s = ((keyPair.getPrivateKey().add(BigInteger.ONE).modInverse(n))
            .multiply((k.subtract(r.multiply(keyPair.getPrivateKey()))).mod(n))).mod(n);

    return new Signature(r, s);
}
 

BNField2(BNParams bn, BigInteger re, BigInteger im, boolean reduce) {
	this.bn = bn;
	if (reduce) {
		if (docount && modenable) {
			if (re.signum() < 0 || re.compareTo(bn.p) >= 0) {
				modcount++;
			}
			if (im.signum() < 0 || im.compareTo(bn.p) >= 0) {
				modcount++;
			}
		}
		this.re = re.mod(bn.p);
		this.im = im.mod(bn.p);
	} else {
		this.re = re;
		this.im = im;
	}
}
 

/**
 * BigInt.asIntN ( bits, bigint )
 * 
 * @param cx
 *            the execution context
 * @param thisValue
 *            the function this-value
 * @param bits
 *            the bits value
 * @param bigint
 *            the bigint value
 * @return the result BigInt value
 */
@Function(name = "asIntN", arity = 2)
public static Object asIntN(ExecutionContext cx, Object thisValue, Object bits, Object bigint) {
    /* step 1 */
    long bitsIndex = ToIndex(cx, bits);
    /* step 2 */
    BigInteger bigIntValue = ToBigInt(cx, bigint);
    /* steps 3-4 */
    if (bitsIndex >= Integer.MAX_VALUE) {
        return bigIntValue;
    }
    if (bitsIndex == 0) {
        return BigInteger.ZERO;
    }
    BigInteger m = BigInteger.valueOf(2).pow((int) bitsIndex);
    BigInteger mod = bigIntValue.mod(m);
    if (mod.compareTo(m.shiftRight(1)) >= 0)
        return mod.subtract(m);
    return mod;
}
 

private static BigInteger gcd1(BigInteger n, BigInteger d) {
    BigInteger n1 = n.abs();
    BigInteger n2 = d.abs();
    BigInteger temp;
    if(n1.equals(new BigInteger("0"))){ // 分子为0， 直接返回1即可
        return  new BigInteger("1");
    }
    if(n1.compareTo(n2) <= 0) { // 确保n1 > n2
        temp = n1;
        n1 = n2;
        n2 = temp;
    }

    temp = n1.mod(n2);
    while(!temp.equals(new BigInteger("0"))){
        n1 = n2;
        n2 = temp;
        temp = n1.mod(n2);
    }
    return n2;
}
 

@Override
protected void compute(BigInteger[] assignment) {

	BigInteger inVal = assignment[inputs[0].getWireId()];
	if (inVal.compareTo(Config.FIELD_PRIME) > 0) {
		inVal = inVal.mod(Config.FIELD_PRIME);
	}
	for (int i = 0; i < outputs.length; i++) {
		assignment[outputs[i].getWireId()] = inVal.testBit(i) ? BigInteger.ONE
				: BigInteger.ZERO;
	}
}
 

public static EC_Params fixedRandomKey(EC_Curve curve) {
    byte[] hash = hashCurve(curve);
    BigInteger priv = new BigInteger(1, hash);
    BigInteger order = new BigInteger(1, curve.getParam(EC_Consts.PARAMETER_R)[0]);
    priv = priv.mod(order);
    return new EC_Params(EC_Consts.PARAMETER_S, new byte[][]{toByteArray(priv, curve.getBits())});
}
 

@Override
public void fetchPermutation(Object[] elements, BigInteger ordinal) {

  if (elements == null)
    throw new NullPointerException("elements array is null.");

  if (ordinal == null)
    throw new NullPointerException("ordinal number is null.");

  if (ordinal.compareTo(BigInteger.ZERO) < 0)
    throw new IllegalArgumentException(
            "ordinal number out of range: " + ordinal);

  if (ordinal.compareTo(getPermutationCount(elements.length)) >= 0)
    throw new IllegalArgumentException(
            "ordinal number out of range: " +
                    ordinal + " / " + getPermutationCount(elements.length));

  for (int i = 0; i < elements.length - 1; i++) {

    int left = elements.length - i - 1;
    BigInteger leftCount = Factorial.of(left);
    int curr = ordinal.divide(leftCount).intValue();
    ordinal = ordinal.mod(leftCount);
    if (curr > 0) {

      Object temp = elements[curr + i];
      for (int j = curr + i; j > i; j--)
        elements[j] = elements[j - 1];
      elements[i] = temp;
    }
  }
}
 

/**
 * Returns public key point from the given private key. To convert a byte array into a BigInteger,
 * use {@code new BigInteger(1, bytes);}
 */
public static ECPoint publicPointFromPrivate(BigInteger privKey) {
    /*
     * TODO: FixedPointCombMultiplier currently doesn't support scalars longer than the group order,
     * but that could change in future versions.
     */
    if (privKey.bitLength() > CURVE.getN().bitLength()) {
        privKey = privKey.mod(CURVE.getN());
    }
    return new FixedPointCombMultiplier().multiply(CURVE.getG(), privKey);
}
 

private static BigInteger truncate(BigInteger x, int bitLength)
{
    if (x.bitLength() > bitLength)
    {
        x = x.mod(ONE.shiftLeft(bitLength));
    }
    return x;
}
 

/**
 * generate a signature for the given message using the key we were
 * initialised with. For conventional DSA the message should be a SHA-1
 * hash of the message of interest.
 *
 * @param message the message that will be verified later.
 */
public BigInteger[] generateSignature(
    byte[] message)
{
    DSAParameters   params = key.getParameters();
    BigInteger      q = params.getQ();
    BigInteger      m = calculateE(q, message);
    BigInteger      x = ((DSAPrivateKeyParameters)key).getX();

    if (kCalculator.isDeterministic())
    {
        kCalculator.init(q, x, message);
    }
    else
    {
        kCalculator.init(q, random);
    }

    BigInteger  k = kCalculator.nextK();

    BigInteger  r = params.getG().modPow(k, params.getP()).mod(q);

    k = k.modInverse(q).multiply(m.add(x.multiply(r)));

    BigInteger  s = k.mod(q);

    return new BigInteger[]{ r, s };
}
 

private BigInteger generateV(BigInteger y, BigInteger p,
         BigInteger q, BigInteger g, BigInteger w, BigInteger r)
         throws SignatureException {

    byte[] s2;
    try {
        s2 = md.digest();
    } catch (RuntimeException re) {
        // Only for RawDSA due to its 20-byte length restriction
        throw new SignatureException(re.getMessage());
    }
    // get the leftmost min(N, outLen) bits of the digest value
    int nBytes = q.bitLength()/8;
    if (nBytes < s2.length) {
        s2 = Arrays.copyOfRange(s2, 0, nBytes);
    }
    BigInteger z = new BigInteger(1, s2);

    BigInteger u1 = z.multiply(w).mod(q);
    BigInteger u2 = (r.multiply(w)).mod(q);

    BigInteger t1 = g.modPow(u1,p);
    BigInteger t2 = y.modPow(u2,p);
    BigInteger t3 = t1.multiply(t2);
    BigInteger t5 = t3.mod(p);
    return t5.mod(q);
}
 

/**
 * Create a normalized BNCurve point from given affine coordinates and a curve
 *
 * @param E the underlying elliptic curve.
 * @param x the affine x-coordinate (mod p).
 * @param y the affine y-coordinate (mod p).
 */
public BNPoint(BNCurve E, BigInteger x, BigInteger y) {
	this.E = E;
	BigInteger p = E.bn.p; // shorthand
	this.x = x.mod(p);
	this.y = y.mod(p);
	this.z = BNParams._1; // normalized
	if (!E.contains(this)) {
		throw new IllegalArgumentException(pointNotOnCurve);
	}
}
 

public static BigInteger jacobiSymbolG(BigInteger a, BigInteger b) {
	BigInteger i1 = a.mod(AbstractIntegerSym.BI_FOUR);
	if (i1.equals(BigInteger.ONE)) {
		return BigInteger.ONE;
	}
	BigInteger i2 = b.mod(AbstractIntegerSym.BI_FOUR);
	if (i2.equals(BigInteger.ONE)) {
		return BigInteger.ONE;
	}
	return AbstractIntegerSym.BI_MINUS_ONE;
}
 

/**
 * encodes the given string into the base of the dictionary provided in the constructor.
 * 
 * @param value the number to encode.
 * @return the encoded string.
 */
public static String encode(Long value) {

  List<Character> result = new ArrayList<Character>();
  BigInteger base = new BigInteger("" + DICTIONARY.length);
  int exponent = 1;
  BigInteger remaining = new BigInteger(value.toString());
  while (true) {
    BigInteger a = base.pow(exponent); // 16^1 = 16
    BigInteger b = remaining.mod(a); // 119 % 16 = 7 | 112 % 256 = 112
    BigInteger c = base.pow(exponent - 1);
    BigInteger d = b.divide(c);

    // if d > dictionary.length, we have a problem. but BigInteger doesnt have
    // a greater than method :-( hope for the best. theoretically, d is always
    // an index of the dictionary!
    result.add(DICTIONARY[d.intValue()]);
    remaining = remaining.subtract(b); // 119 - 7 = 112 | 112 - 112 = 0

    // finished?
    if (remaining.equals(BigInteger.ZERO)) {
      break;
    }

    exponent++;
  }

  // need to reverse it, since the start of the list contains the least significant values
  StringBuffer sb = new StringBuffer();
  for (int i = result.size() - 1; i >= 0; i--) {
    sb.append(result.get(i));
  }
  return sb.toString();
}
 

private BigInteger generateR(BigInteger p, BigInteger q, BigInteger g,
                     BigInteger k) {
    BigInteger temp = g.modPow(k, p);
    return temp.mod(q);
}
 

public KeyPair generateKeyPair() {
    // accommodate odd key sizes in case anybody wants to use them
    int lp = (keySize + 1) >> 1;
    int lq = keySize - lp;
    if (random == null) {
        random = JCAUtil.getSecureRandom();
    }
    BigInteger e = publicExponent;
    while (true) {
        // generate two random primes of size lp/lq
        BigInteger p = BigInteger.probablePrime(lp, random);
        BigInteger q, n;
        do {
            q = BigInteger.probablePrime(lq, random);
            // convention is for p > q
            if (p.compareTo(q) < 0) {
                BigInteger tmp = p;
                p = q;
                q = tmp;
            }
            // modulus n = p * q
            n = p.multiply(q);
            // even with correctly sized p and q, there is a chance that
            // n will be one bit short. re-generate the smaller prime if so
        } while (n.bitLength() < keySize);

        // phi = (p - 1) * (q - 1) must be relative prime to e
        // otherwise RSA just won't work ;-)
        BigInteger p1 = p.subtract(BigInteger.ONE);
        BigInteger q1 = q.subtract(BigInteger.ONE);
        BigInteger phi = p1.multiply(q1);
        // generate new p and q until they work. typically
        // the first try will succeed when using F4
        if (e.gcd(phi).equals(BigInteger.ONE) == false) {
            continue;
        }

        // private exponent d is the inverse of e mod phi
        BigInteger d = e.modInverse(phi);

        // 1st prime exponent pe = d mod (p - 1)
        BigInteger pe = d.mod(p1);
        // 2nd prime exponent qe = d mod (q - 1)
        BigInteger qe = d.mod(q1);

        // crt coefficient coeff is the inverse of q mod p
        BigInteger coeff = q.modInverse(p);

        try {
            PublicKey publicKey = new RSAPublicKeyImpl(n, e);
            PrivateKey privateKey =
                    new RSAPrivateCrtKeyImpl(n, e, d, p, q, pe, qe, coeff);
            return new KeyPair(publicKey, privateKey);
        } catch (InvalidKeyException exc) {
            // invalid key exception only thrown for keys < 512 bit,
            // will not happen here
            throw new RuntimeException(exc);
        }
    }
}
 

private static ECPoint publicPointFromPrivate(BigInteger privKey) {
  if (privKey.bitLength() > CURVE.getN().bitLength()) {
    privKey = privKey.mod(CURVE.getN());
  }
  return new FixedPointCombMultiplier().multiply(CURVE.getG(), privKey);
}
 

private BigInteger generateR(BigInteger p, BigInteger q, BigInteger g,
                     BigInteger k) {
    BigInteger temp = g.modPow(k, p);
    return temp.mod(q);
}