Java Code Examples for org.bouncycastle.crypto.params.ECDomainParameters#getG()

public static KeyPair generateKeyPair(ECDomainParameters domainParameters, SecureRandom random)
        throws NoSuchProviderException, NoSuchAlgorithmException,
        InvalidAlgorithmParameterException {
    KeyPairGenerator kpg = KeyPairGenerator.getInstance(ALGO_NAME_EC, BouncyCastleProvider.PROVIDER_NAME);
    ECParameterSpec parameterSpec = new ECParameterSpec(domainParameters.getCurve(), domainParameters.getG(),
            domainParameters.getN(), domainParameters.getH());
    kpg.initialize(parameterSpec, random);
    return kpg.generateKeyPair();
}
 

/**
 * 将ECC公钥对象转换为X509标准的字节流
 *
 * @param pubKey
 * @return
 */
public static byte[] convertECPublicKeyToX509(ECPublicKeyParameters pubKey) {
    ECDomainParameters domainParams = pubKey.getParameters();
    ECParameterSpec spec = new ECParameterSpec(domainParams.getCurve(), domainParams.getG(),
            domainParams.getN(), domainParams.getH());
    BCECPublicKey publicKey = new BCECPublicKey(ALGO_NAME_EC, pubKey, spec,
            BouncyCastleProvider.CONFIGURATION);
    return publicKey.getEncoded();
}
 

public Sm2KeyPairImpl(boolean selfgen) {
	SecureRandom random = new SecureRandom();
	ECKeyGenerationParameters keyGenerationParams = new ECKeyGenerationParameters(DOMAIN_PARAMS, random);
	ECKeyPairGenerator keyGen = new ECKeyPairGenerator();
	keyGen.init(keyGenerationParams);
	AsymmetricCipherKeyPair keyPair = keyGen.generateKeyPair();
	ECPrivateKeyParameters priKey = (ECPrivateKeyParameters) keyPair.getPrivate();
	ECPublicKeyParameters pubKey = (ECPublicKeyParameters) keyPair.getPublic();
	ECDomainParameters domainParams = priKey.getParameters();
	ECParameterSpec spec = new ECParameterSpec(domainParams.getCurve(), domainParams.getG(), domainParams.getN(),
			domainParams.getH());
	BCECPublicKey bcecPublicKey = new BCECPublicKey(ALGO_NAME_EC, pubKey, spec, BouncyCastleProvider.CONFIGURATION);
	publicKey = new Sm2PublicKeyImpl(bcecPublicKey);
	privateKey = new Sm2PrivateKeyImpl(new BCECPrivateKey(ALGO_NAME_EC, priKey, bcecPublicKey, spec, BouncyCastleProvider.CONFIGURATION));
}
 

public static byte[] convertEcPubKeyToX509Der(ECPublicKeyParameters pubKey) {
    ECDomainParameters domainParams = pubKey.getParameters();
    ECParameterSpec spec = new ECParameterSpec(domainParams.getCurve(), domainParams.getG(),
        domainParams.getN(), domainParams.getH());
    BCECPublicKey publicKey = new BCECPublicKey(ALGO_NAME_EC, pubKey, spec,
        BouncyCastleProvider.CONFIGURATION);
    return publicKey.getEncoded();
}
 

/**
 * return true if the value r and s represent a DSA signature for the passed in
 * message (for standard DSA the message should be a SHA-1 hash of the real
 * message to be verified).
 */
@Override
public boolean verifySignature(byte[] message, BigInteger r, BigInteger s) {
    ECDomainParameters ec = key.getParameters();
    BigInteger n = ec.getN();
    BigInteger e = calculateE(n, message);

    // r in the range [1,n-1]
    if (r.compareTo(ONE) < 0 || r.compareTo(n) >= 0) {
        return false;
    }

    // s in the range [1,n-1]
    if (s.compareTo(ONE) < 0 || s.compareTo(n) >= 0) {
        return false;
    }

    BigInteger c = s.modInverse(n);

    BigInteger u1 = e.multiply(c).mod(n);
    BigInteger u2 = r.multiply(c).mod(n);

    ECPoint G = ec.getG();
    ECPoint Q = ((ECPublicKeyParameters) key).getQ();

    ECPoint point = ECAlgorithms.sumOfTwoMultiplies(G, u1, Q, u2).normalize();

    // components must be bogus.
    if (point.isInfinity()) {
        return false;
    }

    BigInteger v = point.getAffineXCoord().toBigInteger().mod(n);

    return v.equals(r);
}
 

public static KeyPair generateKeyPair(ECDomainParameters domainParameters, SecureRandom random)
    throws NoSuchProviderException, NoSuchAlgorithmException,
    InvalidAlgorithmParameterException {
    KeyPairGenerator kpg = KeyPairGenerator.getInstance(ALGO_NAME_EC, BouncyCastleProvider.PROVIDER_NAME);
    ECParameterSpec parameterSpec = new ECParameterSpec(domainParameters.getCurve(), domainParameters.getG(),
        domainParameters.getN(), domainParameters.getH());
    kpg.initialize(parameterSpec, random);
    return kpg.generateKeyPair();
}
 

/**
 * 将ECC公钥对象转换为X509标准的字节流
 *
 * @param pubKey
 * @return
 */
public static byte[] convertECPublicKeyToX509(ECPublicKeyParameters pubKey) {
    ECDomainParameters domainParams = pubKey.getParameters();
    ECParameterSpec spec = new ECParameterSpec(domainParams.getCurve(), domainParams.getG(),
        domainParams.getN(), domainParams.getH());
    BCECPublicKey publicKey = new BCECPublicKey(ALGO_NAME_EC, pubKey, spec,
        BouncyCastleProvider.CONFIGURATION);
    return publicKey.getEncoded();
}
 

/**
 * return true if the value r and s represent a DSA signature for the passed in message (for
 * standard DSA the message should be a SHA-1 hash of the real message to be verified).
 */
@Override
public boolean verifySignature(byte[] message, BigInteger r, BigInteger s) {
    ECDomainParameters ec = key.getParameters();
    BigInteger n = ec.getN();
    BigInteger e = calculateE(n, message);

    // r in the range [1,n-1]
    if (r.compareTo(ONE) < 0 || r.compareTo(n) >= 0) {
        return false;
    }

    // s in the range [1,n-1]
    if (s.compareTo(ONE) < 0 || s.compareTo(n) >= 0) {
        return false;
    }

    BigInteger c = s.modInverse(n);

    BigInteger u1 = e.multiply(c).mod(n);
    BigInteger u2 = r.multiply(c).mod(n);

    ECPoint G = ec.getG();
    ECPoint Q = ((ECPublicKeyParameters) key).getQ();

    ECPoint point = ECAlgorithms.sumOfTwoMultiplies(G, u1, Q, u2);

    // components must be bogus.
    if (point.isInfinity()) {
        return false;
    }

    /*
     * If possible, avoid normalizing the point (to save a modular inversion in the curve field).
     *
     * There are ~cofactor elements of the curve field that reduce (modulo the group order) to 'r'.
     * If the cofactor is known and small, we generate those possible field values and project each
     * of them to the same "denominator" (depending on the particular projective coordinates in use)
     * as the calculated point.X. If any of the projected values matches point.X, then we have:
     *     (point.X / Denominator mod p) mod n == r
     * as required, and verification succeeds.
     *
     * Based on an original idea by Gregory Maxwell (https://github.com/gmaxwell), as implemented in
     * the libsecp256k1 project (https://github.com/bitcoin/secp256k1).
     */
    ECCurve curve = point.getCurve();
    if (curve != null) {
        BigInteger cofactor = curve.getCofactor();
        if (cofactor != null && cofactor.compareTo(EIGHT) <= 0) {
            ECFieldElement D = getDenominator(curve.getCoordinateSystem(), point);
            if (D != null && !D.isZero()) {
                ECFieldElement X = point.getXCoord();
                while (curve.isValidFieldElement(r)) {
                    ECFieldElement R = curve.fromBigInteger(r).multiply(D);
                    if (R.equals(X)) {
                        return true;
                    }
                    r = r.add(n);
                }
                return false;
            }
        }
    }

    BigInteger v = point.normalize().getAffineXCoord().toBigInteger().mod(n);
    return v.equals(r);
}