Java Code Examples for java.security.spec.EllipticCurve#getField()

The following examples show how to use java.security.spec.EllipticCurve#getField() . You can vote up the ones you like or vote down the ones you don't like, and go to the original project or source file by following the links above each example. You may check out the related API usage on the sidebar.
Example 1
Source File: ECOperations.java    From dragonwell8_jdk with GNU General Public License v2.0 7 votes vote down vote up 
public static Optional<ECOperations> forParameters(ECParameterSpec params) {

        EllipticCurve curve = params.getCurve();
        if (!(curve.getField() instanceof ECFieldFp)) {
            return Optional.empty();
        }
        ECFieldFp primeField = (ECFieldFp) curve.getField();

        BigInteger three = BigInteger.valueOf(3);
        if (!primeField.getP().subtract(curve.getA()).equals(three)) {
            return Optional.empty();
        }
        IntegerFieldModuloP field = fields.get(primeField.getP());
        if (field == null) {
            return Optional.empty();
        }

        IntegerFieldModuloP orderField = orderFields.get(params.getOrder());
        if (orderField == null) {
            return Optional.empty();
        }

        ImmutableIntegerModuloP b = field.getElement(curve.getB());
        ECOperations ecOps = new ECOperations(b, orderField);
        return Optional.of(ecOps);
    }
Example 2
Source File: ECOperations.java    From TencentKona-8 with GNU General Public License v2.0 6 votes vote down vote up 
public static Optional<ECOperations> forParameters(ECParameterSpec params) {

        EllipticCurve curve = params.getCurve();
        if (!(curve.getField() instanceof ECFieldFp)) {
            return Optional.empty();
        }
        ECFieldFp primeField = (ECFieldFp) curve.getField();

        BigInteger three = BigInteger.valueOf(3);
        if (!primeField.getP().subtract(curve.getA()).equals(three)) {
            return Optional.empty();
        }
        IntegerFieldModuloP field = fields.get(primeField.getP());
        if (field == null) {
            return Optional.empty();
        }

        IntegerFieldModuloP orderField = orderFields.get(params.getOrder());
        if (orderField == null) {
            return Optional.empty();
        }

        ImmutableIntegerModuloP b = field.getElement(curve.getB());
        ECOperations ecOps = new ECOperations(b, orderField);
        return Optional.of(ecOps);
    }
Example 3
Source File: ECOperations.java    From openjdk-jdk8u with GNU General Public License v2.0 6 votes vote down vote up 
public static Optional<ECOperations> forParameters(ECParameterSpec params) {

        EllipticCurve curve = params.getCurve();
        if (!(curve.getField() instanceof ECFieldFp)) {
            return Optional.empty();
        }
        ECFieldFp primeField = (ECFieldFp) curve.getField();

        BigInteger three = BigInteger.valueOf(3);
        if (!primeField.getP().subtract(curve.getA()).equals(three)) {
            return Optional.empty();
        }
        IntegerFieldModuloP field = fields.get(primeField.getP());
        if (field == null) {
            return Optional.empty();
        }

        IntegerFieldModuloP orderField = orderFields.get(params.getOrder());
        if (orderField == null) {
            return Optional.empty();
        }

        ImmutableIntegerModuloP b = field.getElement(curve.getB());
        ECOperations ecOps = new ECOperations(b, orderField);
        return Optional.of(ecOps);
    }
Example 4
Source File: EcUtil.java    From wycheproof with Apache License 2.0 6 votes vote down vote up 
public static void printParameters(ECParameterSpec spec) {
  System.out.println("cofactor:" + spec.getCofactor());
  EllipticCurve curve = spec.getCurve();
  System.out.println("A:" + curve.getA());
  System.out.println("B:" + curve.getB());
  ECField field = curve.getField();
  System.out.println("field size:" + field.getFieldSize());
  if (field instanceof ECFieldFp) {
    ECFieldFp fp = (ECFieldFp) field;
    System.out.println("P:" + fp.getP());
  }
  ECPoint generator = spec.getGenerator();
  System.out.println("Gx:" + generator.getAffineX());
  System.out.println("Gy:" + generator.getAffineY());
  System.out.println("order:" + spec.getOrder());
}
Example 5
Source File: EcUtil.java    From wycheproof with Apache License 2.0 6 votes vote down vote up 
/**
 * Decompress a point
 *
 * @param x The x-coordinate of the point
 * @param bit0 true if the least significant bit of y is set.
 * @param ecParams contains the curve of the point. This must be over a prime order field.
 */
public static ECPoint getPoint(BigInteger x, boolean bit0, ECParameterSpec ecParams)
    throws GeneralSecurityException {
  EllipticCurve ec = ecParams.getCurve();
  ECField field = ec.getField();
  if (!(field instanceof ECFieldFp)) {
    throw new GeneralSecurityException("Only curves over prime order fields are supported");
  }
  BigInteger p = ((java.security.spec.ECFieldFp) field).getP();
  if (x.compareTo(BigInteger.ZERO) == -1 || x.compareTo(p) != -1) {
    throw new GeneralSecurityException("x is out of range");
  }
  // Compute rhs == x^3 + a x + b (mod p)
  BigInteger rhs = x.multiply(x).add(ec.getA()).multiply(x).add(ec.getB()).mod(p);
  BigInteger y = modSqrt(rhs, p);
  if (bit0 != y.testBit(0)) {
    y = p.subtract(y).mod(p);
  }
  return new ECPoint(x, y);
}
Example 6
Source File: ECOperations.java    From jdk8u_jdk with GNU General Public License v2.0 6 votes vote down vote up 
public static Optional<ECOperations> forParameters(ECParameterSpec params) {

        EllipticCurve curve = params.getCurve();
        if (!(curve.getField() instanceof ECFieldFp)) {
            return Optional.empty();
        }
        ECFieldFp primeField = (ECFieldFp) curve.getField();

        BigInteger three = BigInteger.valueOf(3);
        if (!primeField.getP().subtract(curve.getA()).equals(three)) {
            return Optional.empty();
        }
        IntegerFieldModuloP field = fields.get(primeField.getP());
        if (field == null) {
            return Optional.empty();
        }

        IntegerFieldModuloP orderField = orderFields.get(params.getOrder());
        if (orderField == null) {
            return Optional.empty();
        }

        ImmutableIntegerModuloP b = field.getElement(curve.getB());
        ECOperations ecOps = new ECOperations(b, orderField);
        return Optional.of(ecOps);
    }
Example 7
Source File: EC5Util.java    From RipplePower with Apache License 2.0 6 votes vote down vote up 
public static ECCurve convertCurve(
    EllipticCurve ec)
{
    ECField field = ec.getField();
    BigInteger a = ec.getA();
    BigInteger b = ec.getB();

    if (field instanceof ECFieldFp)
    {
        ECCurve.Fp curve = new ECCurve.Fp(((ECFieldFp)field).getP(), a, b);

        if (customCurves.containsKey(curve))
        {
            return (ECCurve)customCurves.get(curve);
        }

        return curve;
    }
    else
    {
        ECFieldF2m fieldF2m = (ECFieldF2m)field;
        int m = fieldF2m.getM();
        int ks[] = ECUtil.convertMidTerms(fieldF2m.getMidTermsOfReductionPolynomial());
        return new ECCurve.F2m(m, ks[0], ks[1], ks[2], a, b); 
    }
}
Example 8
Source File: EC5Util.java    From ripple-lib-java with ISC License 6 votes vote down vote up 
public static ECCurve convertCurve(
    EllipticCurve ec)
{
    ECField field = ec.getField();
    BigInteger a = ec.getA();
    BigInteger b = ec.getB();

    if (field instanceof ECFieldFp)
    {
        ECCurve.Fp curve = new ECCurve.Fp(((ECFieldFp)field).getP(), a, b);

        if (customCurves.containsKey(curve))
        {
            return (ECCurve)customCurves.get(curve);
        }

        return curve;
    }
    else
    {
        ECFieldF2m fieldF2m = (ECFieldF2m)field;
        int m = fieldF2m.getM();
        int ks[] = ECUtil.convertMidTerms(fieldF2m.getMidTermsOfReductionPolynomial());
        return new ECCurve.F2m(m, ks[0], ks[1], ks[2], a, b); 
    }
}
Example 9
Source File: EcUtil.java    From wycheproof with Apache License 2.0 5 votes vote down vote up 
/**
 * Returns the modulus of the field used by the curve specified in ecParams.
 *
 * @param curve must be a prime order elliptic curve
 * @return the order of the finite field over which curve is defined.
 */
public static BigInteger getModulus(EllipticCurve curve) throws GeneralSecurityException {
  java.security.spec.ECField field = curve.getField();
  if (field instanceof java.security.spec.ECFieldFp) {
    return ((java.security.spec.ECFieldFp) field).getP();
  } else {
    throw new GeneralSecurityException("Only curves over prime order fields are supported");
  }
}
Example 10
Source File: EcUtil.java    From wycheproof with Apache License 2.0 5 votes vote down vote up 
/**
 * Decompress a point on an elliptic curve.
 *
 * @param bytes The compressed point. Its representation is z || x where z is 2+lsb(y) and x is
 *     using a unsigned fixed length big-endian representation.
 * @param ecParams the specification of the curve. Only Weierstrass curves over prime order fields
 *     are implemented.
 */
public static ECPoint decompressPoint(byte[] bytes, ECParameterSpec ecParams)
    throws GeneralSecurityException {
  EllipticCurve ec = ecParams.getCurve();
  ECField field = ec.getField();
  if (!(field instanceof ECFieldFp)) {
    throw new GeneralSecurityException("Only curves over prime order fields are supported");
  }
  BigInteger p = ((java.security.spec.ECFieldFp) field).getP();
  int expectedLength = 1 + (p.bitLength() + 7) / 8;
  if (bytes.length != expectedLength) {
    throw new GeneralSecurityException("compressed point has wrong length");
  }
  boolean lsb;
  switch (bytes[0]) {
    case 2:
      lsb = false;
      break;
    case 3:
      lsb = true;
      break;
    default:
      throw new GeneralSecurityException("Invalid format");
  }
  BigInteger x = new BigInteger(1, Arrays.copyOfRange(bytes, 1, bytes.length));
  if (x.compareTo(BigInteger.ZERO) == -1 || x.compareTo(p) != -1) {
    throw new GeneralSecurityException("x is out of range");
  }
  // Compute rhs == x^3 + a x + b (mod p)
  BigInteger rhs = x.multiply(x).add(ec.getA()).multiply(x).add(ec.getB()).mod(p);
  BigInteger y = modSqrt(rhs, p);
  if (lsb != y.testBit(0)) {
    y = p.subtract(y).mod(p);
  }
  return new ECPoint(x, y);
}
Example 11
Source File: EcUtil.java    From wycheproof with Apache License 2.0 5 votes vote down vote up 
/**
 * Returns a weak public key of order 3 such that the public key point is on the curve specified
 * in ecParams. This method is used to check ECC implementations for missing step in the
 * verification of the public key. E.g. implementations of ECDH must verify that the public key
 * contains a point on the curve as well as public and secret key are using the same curve.
 *
 * @param ecParams the parameters of the key to attack. This must be a curve in Weierstrass form
 *     over a prime order field.
 * @return a weak EC group with a genrator of order 3.
 */
public static ECPublicKeySpec getWeakPublicKey(ECParameterSpec ecParams)
    throws GeneralSecurityException {
  EllipticCurve curve = ecParams.getCurve();
  KeyPairGenerator keyGen = KeyPairGenerator.getInstance("EC");
  keyGen.initialize(ecParams);
  BigInteger p = getModulus(curve);
  BigInteger three = new BigInteger("3");
  while (true) {
    // Generate a point on the original curve
    KeyPair keyPair = keyGen.generateKeyPair();
    ECPublicKey pub = (ECPublicKey) keyPair.getPublic();
    ECPoint w = pub.getW();
    BigInteger x = w.getAffineX();
    BigInteger y = w.getAffineY();
    // Find the curve parameters a,b such that 3*w = infinity.
    // This is the case if the following equations are satisfied:
    //    3x == l^2 (mod p)
    //    l == (3x^2 + a) / 2*y (mod p)
    //    y^2 == x^3 + ax + b (mod p)
    BigInteger l;
    try {
      l = modSqrt(x.multiply(three), p);
    } catch (GeneralSecurityException ex) {
      continue;
    }
    BigInteger xSqr = x.multiply(x).mod(p);
    BigInteger a = l.multiply(y.add(y)).subtract(xSqr.multiply(three)).mod(p);
    BigInteger b = y.multiply(y).subtract(x.multiply(xSqr.add(a))).mod(p);
    EllipticCurve newCurve = new EllipticCurve(curve.getField(), a, b);
    // Just a sanity check.
    checkPointOnCurve(w, newCurve);
    // Cofactor and order are of course wrong.
    ECParameterSpec spec = new ECParameterSpec(newCurve, w, p, 1);
    return new ECPublicKeySpec(w, spec);
  }
}
Example 12
Source File: ECPointUtil.java    From RipplePower with Apache License 2.0 5 votes vote down vote up 
/**
 * Decode a point on this curve which has been encoded using point
 * compression (X9.62 s 4.2.1 and 4.2.2) or regular encoding.
 * 
 * @param curve
 *            The elliptic curve.
 * @param encoded
 *            The encoded point.
 * @return the decoded point.
 */
public static ECPoint decodePoint(
   EllipticCurve curve, 
   byte[] encoded)
{
    ECCurve c = null;
    
    if (curve.getField() instanceof ECFieldFp)
    {
        c = new ECCurve.Fp(
                ((ECFieldFp)curve.getField()).getP(), curve.getA(), curve.getB());
    }
    else
    {
        int k[] = ((ECFieldF2m)curve.getField()).getMidTermsOfReductionPolynomial();
        
        if (k.length == 3)
        {
            c = new ECCurve.F2m(
                    ((ECFieldF2m)curve.getField()).getM(), k[2], k[1], k[0], curve.getA(), curve.getB());
        }
        else
        {
            c = new ECCurve.F2m(
                    ((ECFieldF2m)curve.getField()).getM(), k[0], curve.getA(), curve.getB());
        }
    }
    
    org.ripple.bouncycastle.math.ec.ECPoint p = c.decodePoint(encoded);

    return new ECPoint(p.getAffineXCoord().toBigInteger(), p.getAffineYCoord().toBigInteger());
}
Example 13
Source File: ECPointUtil.java    From ripple-lib-java with ISC License 5 votes vote down vote up 
/**
 * Decode a point on this curve which has been encoded using point
 * compression (X9.62 s 4.2.1 and 4.2.2) or regular encoding.
 * 
 * @param curve
 *            The elliptic curve.
 * @param encoded
 *            The encoded point.
 * @return the decoded point.
 */
public static ECPoint decodePoint(
   EllipticCurve curve, 
   byte[] encoded)
{
    ECCurve c = null;
    
    if (curve.getField() instanceof ECFieldFp)
    {
        c = new ECCurve.Fp(
                ((ECFieldFp)curve.getField()).getP(), curve.getA(), curve.getB());
    }
    else
    {
        int k[] = ((ECFieldF2m)curve.getField()).getMidTermsOfReductionPolynomial();
        
        if (k.length == 3)
        {
            c = new ECCurve.F2m(
                    ((ECFieldF2m)curve.getField()).getM(), k[2], k[1], k[0], curve.getA(), curve.getB());
        }
        else
        {
            c = new ECCurve.F2m(
                    ((ECFieldF2m)curve.getField()).getM(), k[0], curve.getA(), curve.getB());
        }
    }
    
    org.ripple.bouncycastle.math.ec.ECPoint p = c.decodePoint(encoded);

    return new ECPoint(p.getAffineXCoord().toBigInteger(), p.getAffineYCoord().toBigInteger());
}