Example usage for java.math BigInteger BigInteger

Introduction

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

Prototype

private BigInteger(byte[] magnitude, int signum) 

Source Link

Document

This private constructor is for internal use and assumes that its arguments are correct.

Usage

From source file:Main.java

public static PublicKey getPublicKey(String n, String publicExponent) {
    KeySpec publicKeySpec = new RSAPublicKeySpec(new BigInteger(n, 16), new BigInteger(publicExponent, 16));

    KeyFactory factory = null;//from  w ww.  j  a v  a  2 s  .  c  om
    PublicKey publicKey = null;
    try {
        factory = KeyFactory.getInstance(KEY_ALGORITHM);
    } catch (NoSuchAlgorithmException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
        return null;
    }

    try {
        publicKey = factory.generatePublic(publicKeySpec);
    } catch (InvalidKeySpecException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
        return null;
    }

    return publicKey;
}

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From source file:Main.java

public static boolean isGoodPrime(byte[] prime, int g) {
    if (!(g >= 2 && g <= 7)) {
        return false;
    }/*from   w ww.  j  ava2 s. 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

public static BigInteger getZ(ArrayList<byte[]> c1, ArrayList<byte[]> c2, BigInteger p) {
    BigInteger z = BigInteger.ZERO;

    //TODO: make sure c1 and c2 are of the same size
    int size = c1.size();
    if (size > c2.size()) {
        size = c2.size();/*  w  ww  . j a  v a2 s  .  c  o  m*/
    }

    for (int i = 0; i < size; i++) {
        BigInteger c1BI = new BigInteger(1, c1.get(i));
        BigInteger c2BI = new BigInteger(1, c2.get(i));
        BigInteger exp = new BigInteger(1, ByteBuffer.allocate(8).putLong((long) Math.pow(2, i)).array());

        z = z.add((c1BI.multiply(c2BI)).modPow(exp, p));
        Log.d("CeCk", "z calculation " + i + "/" + size + " round");
    }
    return z.mod(p);
}

---

From source file:Main.java

public static byte[] getRSAEncryptedData(byte[] dataWithHash) {
    BigInteger modulus = new BigInteger(
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
            16);/*from ww  w  .j  a v  a 2 s .  com*/
    BigInteger pubExp = new BigInteger("010001", 16);

    KeyFactory keyFactory = null;
    try {
        keyFactory = KeyFactory.getInstance("RSA");
        RSAPublicKeySpec pubKeySpec = new RSAPublicKeySpec(modulus, pubExp);
        RSAPublicKey key = (RSAPublicKey) keyFactory.generatePublic(pubKeySpec);

        Cipher cipher = Cipher.getInstance("RSA/ECB/NoPadding");
        cipher.init(Cipher.ENCRYPT_MODE, key);
        byte[] cipherData = cipher.doFinal(dataWithHash);
    } catch (NoSuchAlgorithmException e) {
        e.printStackTrace(); //To change body of catch statement use File | Settings | File Templates.
    } catch (IllegalBlockSizeException e) {
        e.printStackTrace(); //To change body of catch statement use File | Settings | File Templates.
    } catch (InvalidKeyException e) {
        e.printStackTrace(); //To change body of catch statement use File | Settings | File Templates.
    } catch (BadPaddingException e) {
        e.printStackTrace(); //To change body of catch statement use File | Settings | File Templates.
    } catch (InvalidKeySpecException e) {
        e.printStackTrace(); //To change body of catch statement use File | Settings | File Templates.
    } catch (NoSuchPaddingException e) {
        e.printStackTrace(); //To change body of catch statement use File | Settings | File Templates.
    }
    return null;
}

---

From source file:Main.java

public static String sha1(String s) {
    if (mSha1Digest == null) {
        try {/*w  ww . j  av a2  s .  com*/
            mSha1Digest = MessageDigest.getInstance("SHA-1");
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }
    }
    byte[] data = mSha1Digest.digest(s.getBytes());
    return String.format("%0" + (data.length * 2) + "X", new BigInteger(1, data));
}

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From source file:Main.java

public static String getPwdHash(String password, String salt) {
    try {//from   ww  w. j a  v a2 s.  c o m
        String temp = password + salt;
        MessageDigest md = MessageDigest.getInstance("SHA-256");

        md.update(temp.getBytes("UTF-8")); // Change this to "UTF-16" if needed
        byte[] digest = md.digest();
        return String.format("%0" + (digest.length * 2) + 'x', new BigInteger(1, digest));
    } catch (NoSuchAlgorithmException e) {
        throw new RuntimeException(e);
    } catch (UnsupportedEncodingException e) {
        throw new RuntimeException(e);
    }
}

---

From source file:Main.java

/**
 * Calculates an MD5 hash for a text.//from  w  ww.j  a  va 2s .c  o m
 * 
 * @param dataToEncode
 *            The data to encode.
 * @return A text representation of a hexadecimal value of length 32.
 */
public static String messageDigestFive(final String dataToEncode) {
    MessageDigest m;
    try {
        m = MessageDigest.getInstance("MD5");
        byte[] data = dataToEncode.getBytes();
        m.update(data, 0, data.length);
        BigInteger i = new BigInteger(1, m.digest());
        return String.format("%1$032X", i);
    } catch (NoSuchAlgorithmException e) {
        // MD5 Should be supported by the runtime!
        throw new IllegalStateException(e);
    }
}

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From source file:Main.java

private static String computeSignature(String baseString, String keyString)
        throws GeneralSecurityException, UnsupportedEncodingException {
    Mac mac = Mac.getInstance("HmacSHA256");
    SecretKeySpec secret = new SecretKeySpec(keyString.getBytes("UTF-8"), "HmacSHA256");
    mac.init(secret);//from w w w  .  j a  v  a  2  s  . c om
    byte[] byteData = mac.doFinal(baseString.getBytes("UTF-8"));

    BigInteger hash = new BigInteger(1, byteData);
    String hmac = hash.toString(16);

    if (hmac.length() % 2 != 0) {
        hmac = "0" + hmac;
    }

    return hmac;
}

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From source file:business.security.SecureTokenGenerator.java

public static String generateToken() {
    return new BigInteger(130, rng).toString(32);
}

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From source file:Main.java

public static String md5Calc(File f) {
    int i;//w  w w  . j a v  a2s  . c o  m

    byte[] buffer = new byte[1024];
    int read = 0;
    String md5hash;
    try {
        MessageDigest digest = MessageDigest.getInstance("MD5");
        InputStream is = new FileInputStream(f);
        while ((read = is.read(buffer)) > 0) {
            digest.update(buffer, 0, read);
        }
        byte[] md5sum = digest.digest();
        BigInteger bigInt = new BigInteger(1, md5sum);
        md5hash = bigInt.toString(16);
        is.close();
    } catch (Exception e) {
        e.printStackTrace();
        return null;
    }

    if (md5hash.length() != 33) {
        String tmp = "";
        for (i = 1; i < (33 - md5hash.length()); i++) {
            tmp = tmp.concat("0");
        }
        md5hash = tmp.concat(md5hash);
    }

    return md5hash;
}

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