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

The following examples show how to use java.security.spec.EllipticCurve#getA() . 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: 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 2
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 3
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 4
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());
}
Example 5
Source File: EcDef.java    From swim with Apache License 2.0 4 votes vote down vote up 
public static EcDef from(EllipticCurve curve) {
  return new EcDef(EcFieldDef.from(curve.getField()), curve.getA(),
      curve.getB(), curve.getSeed());
}
Example 6
Source File: JweUtils.java    From cxf with Apache License 2.0 4 votes vote down vote up 
public static byte[] getECDHKey(ECPrivateKey privateKey,
                                ECPublicKey peerPublicKey,
                                byte[] partyUInfo,
                                byte[] partyVInfo,
                                String algoName,
                                int algoKeyBitLen) {
    // Validate the peerPublicKey first

    // Credits:
    // https://neilmadden.wordpress.com/2017/05/17/so-how-do-you-validate-nist-ecdh-public-keys/
    // https://blogs.adobe.com/security/2017/03/critical-vulnerability-uncovered-in-json-encryption.html

    // Step 1: Verify public key is not point at infinity.
    if (ECPoint.POINT_INFINITY.equals(peerPublicKey.getW())) {
        throw new JweException(JweException.Error.KEY_ENCRYPTION_FAILURE);
    }
    EllipticCurve curve = peerPublicKey.getParams().getCurve();

    final BigInteger x = peerPublicKey.getW().getAffineX();
    final BigInteger y = peerPublicKey.getW().getAffineY();
    final BigInteger p = ((ECFieldFp) curve.getField()).getP();

    // Step 2: Verify x and y are in range [0,p-1]
    if (x.compareTo(BigInteger.ZERO) < 0 || x.compareTo(p) >= 0
            || y.compareTo(BigInteger.ZERO) < 0 || y.compareTo(p) >= 0) {
        throw new JweException(JweException.Error.KEY_ENCRYPTION_FAILURE);
    }
    final BigInteger a = curve.getA();
    final BigInteger b = curve.getB();

    // Step 3: Verify that y^2 == x^3 + ax + b (mod p)
    final BigInteger ySquared = y.modPow(BigInteger.valueOf(2), p);
    final BigInteger xCubedPlusAXPlusB = x.modPow(BigInteger.valueOf(3), p).add(a.multiply(x)).add(b).mod(p);
    if (!ySquared.equals(xCubedPlusAXPlusB)) {
        throw new JweException(JweException.Error.KEY_ENCRYPTION_FAILURE);
    }

    // Step 4: Verify that nQ = 0, where n is the order of the curve and Q is the public key.
    // As per http://www.secg.org/sec1-v2.pdf section 3.2.2:
    // "In Step 4, it may not be necessary to compute the point nQ. For example, if h = 1, then nQ = O is implied
    // by the checks in Steps 2 and 3, because this property holds for all points Q ∈ E"
    // All the NIST curves used here define h = 1.
    if (peerPublicKey.getParams().getCofactor() != 1) {
        throw new JweException(JweException.Error.KEY_ENCRYPTION_FAILURE);
    }

    // Finally calculate the derived key

    byte[] keyZ = generateKeyZ(privateKey, peerPublicKey);
    return calculateDerivedKey(keyZ, algoName, partyUInfo, partyVInfo, algoKeyBitLen);
}