Java Code Examples for java.math.BigInteger#signum()
The following examples show how to use
java.math.BigInteger#signum() .
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Example 1
Source File: RationalNumber.java From astor with GNU General Public License v2.0 | 6 votes |
/** Simple constructor. * Build a rational number from a numerator and a denominator. * @param numerator numerator of the rational number * @param denominator denominator of the rational number * @exception ArithmeticException if the denominator is zero */ public RationalNumber(BigInteger numerator, BigInteger denominator) { if (denominator.signum() == 0) { throw new ArithmeticException("divide by zero"); } p = numerator; q = denominator; if (q.signum() < 0) { p = p.negate(); q = q.negate(); } simplify(); }
Example 2
Source File: SecureBox.java From android_9.0.0_r45 with Apache License 2.0 | 6 votes |
private static void validateEcPoint(BigInteger x, BigInteger y) throws InvalidKeyException { if (x.compareTo(EC_PARAM_P) >= 0 || y.compareTo(EC_PARAM_P) >= 0 || x.signum() == -1 || y.signum() == -1) { throw new InvalidKeyException("Point lies outside of the expected curve"); } // Points on the curve satisfy y^2 = x^3 + ax + b (mod p) BigInteger lhs = y.modPow(BIG_INT_02, EC_PARAM_P); BigInteger rhs = x.modPow(BIG_INT_02, EC_PARAM_P) // x^2 .add(EC_PARAM_A) // x^2 + a .mod(EC_PARAM_P) // This will speed up the next multiplication .multiply(x) // (x^2 + a) * x = x^3 + ax .add(EC_PARAM_B) // x^3 + ax + b .mod(EC_PARAM_P); if (!lhs.equals(rhs)) { throw new InvalidKeyException("Point lies outside of the expected curve"); } }
Example 3
Source File: Gmp.java From jna-gmp with Apache License 2.0 | 6 votes |
private BigInteger modPowSecureImpl(BigInteger base, BigInteger exp, BigInteger mod) { boolean invert = exp.signum() < 0; if (invert) { exp = exp.negate(); } mpz_t basePeer = getPeer(base, sharedOperands[0]); mpz_t expPeer = getPeer(exp, sharedOperands[1]); mpz_t modPeer = getPeer(mod, sharedOperands[2]); if (invert) { int res = __gmpz_invert(basePeer, basePeer, modPeer); if (res == 0) { throw new ArithmeticException("val not invertible"); } } __gmpz_powm_sec(sharedOperands[3], basePeer, expPeer, modPeer); // The result size should be <= modulus size, but round up to the nearest byte. int requiredSize = (mod.bitLength() + 7) / 8; return new BigInteger(mpzSgn(sharedOperands[3]), mpzExport(sharedOperands[3], requiredSize)); }
Example 4
Source File: NumericType.java From etherjar with Apache License 2.0 | 6 votes |
@Override public Hex32 encodeSimple(BigInteger value) { if (!isValueValid(value)) throw new IllegalArgumentException("Numeric value out of range: " + value); byte[] data = value.toByteArray(); byte[] arr = new byte[Hex32.SIZE_BYTES]; if (value.signum() == -1) { System.arraycopy(NEGATIVE_ARRAY_FOR_PADDING, 0, arr, 0, Hex32.SIZE_BYTES); } int bytes = bits >>> 3; if (data.length > bytes) { System.arraycopy(data, data.length - bytes, arr, Hex32.SIZE_BYTES - bytes, bytes); } else { System.arraycopy(data, 0, arr, Hex32.SIZE_BYTES - data.length, data.length); } return new Hex32(arr); }
Example 5
Source File: ECAlgorithms.java From RipplePower with Apache License 2.0 | 6 votes |
static ECPoint implShamirsTrickWNaf(ECPoint P, BigInteger k, ECPoint Q, BigInteger l) { boolean negK = k.signum() < 0, negL = l.signum() < 0; k = k.abs(); l = l.abs(); int widthP = Math.max(2, Math.min(16, WNafUtil.getWindowSize(k.bitLength()))); int widthQ = Math.max(2, Math.min(16, WNafUtil.getWindowSize(l.bitLength()))); WNafPreCompInfo infoP = WNafUtil.precompute(P, widthP, true); WNafPreCompInfo infoQ = WNafUtil.precompute(Q, widthQ, true); ECPoint[] preCompP = negK ? infoP.getPreCompNeg() : infoP.getPreComp(); ECPoint[] preCompQ = negL ? infoQ.getPreCompNeg() : infoQ.getPreComp(); ECPoint[] preCompNegP = negK ? infoP.getPreComp() : infoP.getPreCompNeg(); ECPoint[] preCompNegQ = negL ? infoQ.getPreComp() : infoQ.getPreCompNeg(); byte[] wnafP = WNafUtil.generateWindowNaf(widthP, k); byte[] wnafQ = WNafUtil.generateWindowNaf(widthQ, l); return implShamirsTrickWNaf(preCompP, preCompNegP, wnafP, preCompQ, preCompNegQ, wnafQ); }
Example 6
Source File: ModInvTime.java From openjdk-jdk8u with GNU General Public License v2.0 | 5 votes |
public static void check(BigInteger val, BigInteger mod, BigInteger inv) { BigInteger r = inv.multiply(val).remainder(mod); if (r.signum() == -1) r = r.add(mod); if (!r.equals(BigInteger.ONE)) throw new RuntimeException("Numerically incorrect modular inverse"); }
Example 7
Source File: TestFDBigInteger.java From jdk8u_jdk with GNU General Public License v2.0 | 5 votes |
private static void testMultByPow52(FDBigInteger t, int p5, int p2) throws Exception { BigInteger bt = t.toBigInteger(); FDBigInteger r = t.multByPow52(p5, p2); if (bt.signum() == 0 && r != t) { throw new Exception("multByPow52 of doesn't reuse its argument"); } check(bt.multiply(biPow52(p5, p2)), r, "multByPow52 returns wrong result"); }
Example 8
Source File: TestFDBigInteger.java From jdk8u_jdk with GNU General Public License v2.0 | 5 votes |
private static void testLeftShift(FDBigInteger t, int shift, boolean isImmutable) throws Exception { BigInteger bt = t.toBigInteger(); FDBigInteger r = t.leftShift(shift); if ((bt.signum() == 0 || shift == 0 || !isImmutable) && r != t) { throw new Exception("leftShift doesn't reuse its argument"); } if (isImmutable) { check(bt, t, "leftShift corrupts its argument"); } check(bt.shiftLeft(shift), r, "leftShift returns wrong result"); }
Example 9
Source File: Curve25519FieldElement.java From RipplePower with Apache License 2.0 | 5 votes |
public Curve25519FieldElement(BigInteger x) { if (x == null || x.signum() < 0 || x.compareTo(Q) >= 0) { throw new IllegalArgumentException("x value invalid for Curve25519FieldElement"); } this.x = Curve25519Field.fromBigInteger(x); }
Example 10
Source File: WNafUtil.java From RipplePower with Apache License 2.0 | 5 votes |
public static byte[] generateNaf(BigInteger k) { if (k.signum() == 0) { return EMPTY_BYTES; } BigInteger _3k = k.shiftLeft(1).add(k); int digits = _3k.bitLength() - 1; byte[] naf = new byte[digits]; BigInteger diff = _3k.xor(k); for (int i = 1; i < digits; ++i) { if (diff.testBit(i)) { naf[i - 1] = (byte)(k.testBit(i) ? -1 : 1); ++i; } } naf[digits - 1] = 1; return naf; }
Example 11
Source File: RSACore.java From openjdk-8-source with GNU General Public License v2.0 | 5 votes |
/** * RSA private key operations with CRT. Algorithm and variable naming * are taken from PKCS#1 v2.1, section 5.1.2. * * The only difference is the addition of blinding to twart timing attacks. * This is described in the RSA Bulletin#2 (Jan 96) among other places. * This means instead of implementing RSA as * m = c ^ d mod n (or RSA in CRT variant) * we do * r = random(0, n-1) * c' = c * r^e mod n * m' = c' ^ d mod n (or RSA in CRT variant) * m = m' * r^-1 mod n (where r^-1 is the modular inverse of r mod n) * This works because r^(e*d) * r^-1 = r * r^-1 = 1 (all mod n) * * We do not generate new blinding parameters for each operation but reuse * them BLINDING_MAX_REUSE times (see definition below). */ private static byte[] crtCrypt(byte[] msg, RSAPrivateCrtKey key) throws BadPaddingException { BigInteger n = key.getModulus(); BigInteger c = parseMsg(msg, n); BigInteger p = key.getPrimeP(); BigInteger q = key.getPrimeQ(); BigInteger dP = key.getPrimeExponentP(); BigInteger dQ = key.getPrimeExponentQ(); BigInteger qInv = key.getCrtCoefficient(); BlindingParameters params; if (ENABLE_BLINDING) { params = getBlindingParameters(key); c = c.multiply(params.re).mod(n); } else { params = null; } // m1 = c ^ dP mod p BigInteger m1 = c.modPow(dP, p); // m2 = c ^ dQ mod q BigInteger m2 = c.modPow(dQ, q); // h = (m1 - m2) * qInv mod p BigInteger mtmp = m1.subtract(m2); if (mtmp.signum() < 0) { mtmp = mtmp.add(p); } BigInteger h = mtmp.multiply(qInv).mod(p); // m = m2 + q * h BigInteger m = h.multiply(q).add(m2); if (params != null) { m = m.multiply(params.rInv).mod(n); } return toByteArray(m, getByteLength(n)); }
Example 12
Source File: SuperSerial.java From headlong with Apache License 2.0 | 5 votes |
private static byte[] toSigned(int typeBits, BigInteger val) { final int signum = val.signum(); if(signum == 0) { return Strings.EMPTY_BYTE_ARRAY; } final byte[] bytes = val.toByteArray(); return signum < 0 ? signExtendNegative(bytes, typeBits / Byte.SIZE) : bytes[0] != 0 ? bytes : Arrays.copyOfRange(bytes, 1, bytes.length); }
Example 13
Source File: Strings.java From JavaSteam with MIT License | 5 votes |
public String asUnsignedDecimalString(long l) { BigInteger b = BigInteger.valueOf(l); if (b.signum() < 0) { b = b.add(TWO_64); } return b.toString(); }
Example 14
Source File: DSAKeyPairGenerator.java From openjdk-8 with GNU General Public License v2.0 | 5 votes |
/** * Generate the private key component of the key pair using the * provided source of random bits. This method uses the random but * source passed to generate a seed and then calls the seed-based * generateX method. */ private BigInteger generateX(SecureRandom random, BigInteger q) { BigInteger x = null; byte[] temp = new byte[qlen]; while (true) { random.nextBytes(temp); x = new BigInteger(1, temp).mod(q); if (x.signum() > 0 && (x.compareTo(q) < 0)) { return x; } } }
Example 15
Source File: ObjectIdentifier.java From dragonwell8_jdk with GNU General Public License v2.0 | 5 votes |
private static void checkFirstComponent(BigInteger first) throws IOException { if (first.signum() == -1 || first.compareTo(BigInteger.valueOf(2)) == 1) { throw new IOException("ObjectIdentifier() -- " + "First oid component is invalid "); } }
Example 16
Source File: CompactNumberFormat.java From Bytecoder with Apache License 2.0 | 4 votes |
private StringBuffer format(BigInteger number, StringBuffer result, FieldDelegate delegate, boolean formatLong) { boolean isNegative = number.signum() == -1; if (isNegative) { number = number.negate(); } int compactDataIndex = selectCompactPattern(number); if (compactDataIndex != -1) { Number divisor = divisors.get(compactDataIndex); int iPart = getIntegerPart(number.doubleValue(), divisor.doubleValue()); String prefix = getAffix(false, true, isNegative, compactDataIndex, iPart); String suffix = getAffix(false, false, isNegative, compactDataIndex, iPart); if (!prefix.isEmpty() || !suffix.isEmpty()) { appendPrefix(result, prefix, delegate); if (number.mod(new BigInteger(divisor.toString())) .compareTo(BigInteger.ZERO) == 0) { number = number.divide(new BigInteger(divisor.toString())); decimalFormat.setDigitList(number, isNegative, 0); decimalFormat.subformatNumber(result, delegate, isNegative, true, getMaximumIntegerDigits(), getMinimumIntegerDigits(), getMaximumFractionDigits(), getMinimumFractionDigits()); } else { // To avoid truncation of fractional part store the value in // BigDecimal and follow BigDecimal path instead of // BigInteger path BigDecimal nDecimal = new BigDecimal(number) .divide(new BigDecimal(divisor.toString()), getRoundingMode()); decimalFormat.setDigitList(nDecimal, isNegative, getMaximumFractionDigits()); decimalFormat.subformatNumber(result, delegate, isNegative, false, getMaximumIntegerDigits(), getMinimumIntegerDigits(), getMaximumFractionDigits(), getMinimumFractionDigits()); } appendSuffix(result, suffix, delegate); } else { number = isNegative ? number.negate() : number; defaultDecimalFormat.format(number, result, delegate, formatLong); } } else { number = isNegative ? number.negate() : number; defaultDecimalFormat.format(number, result, delegate, formatLong); } return result; }
Example 17
Source File: NumberUtil.java From symja_android_library with GNU General Public License v3.0 | 4 votes |
public static BigInteger checkPositive(String role, BigInteger x) { if (x.signum() <= 0) { throw new IllegalArgumentException(role + " (" + x + ") must be > 0"); } return x; }
Example 18
Source File: ObjectIdentifier.java From hottub with GNU General Public License v2.0 | 4 votes |
private static void checkOtherComponent(int i, BigInteger num) throws IOException { if (num.signum() == -1) { throw new IOException("ObjectIdentifier() -- " + "oid component #" + (i+1) + " must be non-negative "); } }
Example 19
Source File: ECFieldFp.java From jdk1.8-source-analysis with Apache License 2.0 | 3 votes |
/** * Creates an elliptic curve prime finite field * with the specified prime {@code p}. * @param p the prime. * @exception NullPointerException if {@code p} is null. * @exception IllegalArgumentException if {@code p} * is not positive. */ public ECFieldFp(BigInteger p) { if (p.signum() != 1) { throw new IllegalArgumentException("p is not positive"); } this.p = p; }
Example 20
Source File: ECFieldFp.java From j2objc with Apache License 2.0 | 3 votes |
/** * Creates an elliptic curve prime finite field * with the specified prime {@code p}. * @param p the prime. * @exception NullPointerException if {@code p} is null. * @exception IllegalArgumentException if {@code p} * is not positive. */ public ECFieldFp(BigInteger p) { if (p.signum() != 1) { throw new IllegalArgumentException("p is not positive"); } this.p = p; }