Example usage for java.math BigInteger valueOf

List of usage examples for java.math BigInteger valueOf

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Introduction

In this page you can find the example usage for java.math BigInteger valueOf.

Prototype

private static BigInteger valueOf(int val[])

Source Link

Document

Returns a BigInteger with the given two's complement representation.

Usage

From source file:Main.java

private static BigInteger findSquareRoot(BigInteger alpha, BigInteger p) {
    BigInteger beta = null;//from   ww  w.j a va2s. com
    if (p.mod(BigInteger.valueOf(4)).compareTo(BigInteger.valueOf(3)) == 0) {
        BigInteger k = p.shiftRight(2).add(ONE);
        beta = alpha.modPow(k, p);
    } else if (p.mod(BigInteger.valueOf(8)).compareTo(BigInteger.valueOf(5)) == 0) {
        System.out.println("p = 8 mod 5");
        BigInteger k = p.subtract(BigInteger.valueOf(5)).divide(BigInteger.valueOf(8));
        BigInteger gamma = alpha.multiply(BigInteger.valueOf(2)).modPow(k, p);
        BigInteger i = alpha.multiply(BigInteger.valueOf(2)).multiply(gamma.pow(2)).mod(p);
        beta = alpha.multiply(gamma).multiply(i.subtract(ONE)).mod(p);
    } else if (p.mod(BigInteger.valueOf(8)).compareTo(BigInteger.valueOf(1)) == 0) {
        beta = null;
        //TODO
        System.out.println("finding square root not fully implemented yet");
    }
    return beta;
}

From source file:Main.java

public static BigInteger byteArrayToBigInteger(byte[] b, int offset, int length) {
    if (b.length < offset + length) {
        throw new IllegalArgumentException("offset + length must be less than or equal to b.length");
    }/*from  ww w . j  av  a2 s.  co  m*/

    BigInteger value = BigInteger.valueOf(0);
    for (int i = 0; i < length; i++) {
        value = value.shiftLeft(8);
        value = value.add(BigInteger.valueOf(b[i + offset] & 0x000000ff));
    }
    return value;
}

From source file:Main.java

public static final BigInteger castToBigInteger(Object paramObject) {
    if (paramObject == null) {
        return null;
    }// w ww . jav a 2  s .  c  o m
    if ((paramObject instanceof BigInteger)) {
        return (BigInteger) paramObject;
    }
    if (((paramObject instanceof Float)) || ((paramObject instanceof Double))) {
        return BigInteger.valueOf(((Number) paramObject).longValue());
    }
    String str = paramObject.toString();
    if (str.length() == 0) {
        return null;
    }
    return new BigInteger(str);
}

From source file:Main.java

/**
 * Converts a BigInteger array into an integer array, reducing all
 * BigIntegers mod q./*from   ww  w  .  j  a v a2  s.c  o m*/
 *
 * @param q     -
 *              the modulus
 * @param input -
 *              the BigInteger array
 * @return the integer array
 */
public static int[] toIntArrayModQ(int q, BigInteger[] input) {
    BigInteger bq = BigInteger.valueOf(q);
    int[] result = new int[input.length];
    for (int i = 0; i < input.length; i++) {
        result[i] = input[i].mod(bq).intValue();
    }
    return result;
}

From source file:Main.java

public static BigInteger hashFnv1A(byte[] data) {
    final BigInteger INIT64 = new BigInteger("cbf29ce484222325", 16);
    final BigInteger PRIME64 = new BigInteger("100000001b3", 16);
    final BigInteger MOD64 = new BigInteger("2").pow(64);

    BigInteger hash = INIT64;//from ww w. j ava 2s  .  co m

    for (byte b : data) {
        hash = hash.xor(BigInteger.valueOf((int) b & 0xff));
        hash = hash.multiply(PRIME64).mod(MOD64);
    }

    return hash;
}

From source file:Main.java

public static Date toDate(Instant instant) {
    BigInteger milis = BigInteger.valueOf(instant.getEpochSecond()).multiply(BigInteger.valueOf(1000));
    milis = milis.add(BigInteger.valueOf(instant.getNano()).divide(BigInteger.valueOf(1_000_000)));
    return new Date(milis.longValue());
}

From source file:Main.java

/**
 * @param value A number/* ww  w .ja va  2s  .com*/
 *
 * @return The number as a {@link BigInteger}.
 */
public static BigInteger asBigInteger(Number number) {
    if (number == null) {
        return null;
    }

    if (number instanceof BigInteger) {
        return (BigInteger) number;
    }

    return BigInteger.valueOf(number.longValue());
}

From source file:Main.java

public static boolean isGoodPrime(byte[] prime, int g) {
    if (!(g >= 2 && g <= 7)) {
        return false;
    }/*ww  w .  ja  va  2s .  c  o m*/

    if (prime.length != 256 || prime[0] >= 0) {
        return false;
    }

    BigInteger dhBI = new BigInteger(1, prime);

    if (g == 2) { // p mod 8 = 7 for g = 2;
        BigInteger res = dhBI.mod(BigInteger.valueOf(8));
        if (res.intValue() != 7) {
            return false;
        }
    } else if (g == 3) { // p mod 3 = 2 for g = 3;
        BigInteger res = dhBI.mod(BigInteger.valueOf(3));
        if (res.intValue() != 2) {
            return false;
        }
    } else if (g == 5) { // p mod 5 = 1 or 4 for g = 5;
        BigInteger res = dhBI.mod(BigInteger.valueOf(5));
        int val = res.intValue();
        if (val != 1 && val != 4) {
            return false;
        }
    } else if (g == 6) { // p mod 24 = 19 or 23 for g = 6;
        BigInteger res = dhBI.mod(BigInteger.valueOf(24));
        int val = res.intValue();
        if (val != 19 && val != 23) {
            return false;
        }
    } else if (g == 7) { // p mod 7 = 3, 5 or 6 for g = 7.
        BigInteger res = dhBI.mod(BigInteger.valueOf(7));
        int val = res.intValue();
        if (val != 3 && val != 5 && val != 6) {
            return false;
        }
    }

    String hex = bytesToHex(prime);
    if (hex.equals(
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{
        return true;
    }

    BigInteger dhBI2 = dhBI.subtract(BigInteger.valueOf(1)).divide(BigInteger.valueOf(2));
    return !(!dhBI.isProbablePrime(30) || !dhBI2.isProbablePrime(30));
}

From source file:Main.java

private static boolean passesMillerRabin(BigInteger us, int iterations, Random rnd) {
    final BigInteger ONE = BigInteger.ONE;
    final BigInteger TWO = BigInteger.valueOf(2);
    // Find a and m such that m is odd and this == 1 + 2**a * m
    BigInteger thisMinusOne = us.subtract(ONE);
    BigInteger m = thisMinusOne;//from w w  w . j a  v  a2s . c  o m
    int a = m.getLowestSetBit();
    m = m.shiftRight(a);

    // Do the tests
    if (rnd == null) {
        rnd = new SecureRandom();
    }
    for (int i = 0; i < iterations; i++) {
        // Generate a uniform random on (1, this)
        BigInteger b;
        do {
            b = new BigInteger(us.bitLength(), rnd);
        } while (b.compareTo(ONE) <= 0 || b.compareTo(us) >= 0);

        int j = 0;
        BigInteger z = b.modPow(m, us);
        while (!((j == 0 && z.equals(ONE)) || z.equals(thisMinusOne))) {
            if (j > 0 && z.equals(ONE) || ++j == a)
                return false;
            z = z.modPow(TWO, us);
        }
    }
    return true;
}

From source file:MainClass.java

public static X509Certificate generateV3Certificate(KeyPair pair)
        throws InvalidKeyException, NoSuchProviderException, SignatureException {
    Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());

    X509V3CertificateGenerator certGen = new X509V3CertificateGenerator();

    certGen.setSerialNumber(BigInteger.valueOf(System.currentTimeMillis()));
    certGen.setIssuerDN(new X500Principal("CN=Test Certificate"));
    certGen.setNotBefore(new Date(System.currentTimeMillis() - 10000));
    certGen.setNotAfter(new Date(System.currentTimeMillis() + 10000));
    certGen.setSubjectDN(new X500Principal("CN=Test Certificate"));
    certGen.setPublicKey(pair.getPublic());
    certGen.setSignatureAlgorithm("SHA256WithRSAEncryption");

    certGen.addExtension(X509Extensions.BasicConstraints, true, new BasicConstraints(false));
    certGen.addExtension(X509Extensions.KeyUsage, true,
            new KeyUsage(KeyUsage.digitalSignature | KeyUsage.keyEncipherment));
    certGen.addExtension(X509Extensions.ExtendedKeyUsage, true,
            new ExtendedKeyUsage(KeyPurposeId.id_kp_serverAuth));

    certGen.addExtension(X509Extensions.SubjectAlternativeName, false,
            new GeneralNames(new GeneralName(GeneralName.rfc822Name, "test@test.test")));

    return certGen.generateX509Certificate(pair.getPrivate(), "BC");
}