import org.bouncycastle.math.ec.FixedPointCombMultiplier; //导入依赖的package包/类
public byte[] generateSignatureForHash(byte[] eHash) throws CryptoException {
    BigInteger n = ecParams.getN();
    BigInteger e = new BigInteger(1, eHash);
    BigInteger d = ((ECPrivateKeyParameters)ecKey).getD();

    BigInteger r, s;

    ECMultiplier basePointMultiplier = new FixedPointCombMultiplier();

    // 5.2.1 Draft RFC:  SM2 Public Key Algorithms
    do {// generate s
        BigInteger k;
        do { // generate r
            // A3
            k = kCalculator.nextK();

            // A4
            ECPoint p = basePointMultiplier.multiply(ecParams.getG(), k).normalize();

            // A5
            r = e.add(p.getAffineXCoord().toBigInteger()).mod(n);
        } while (r.equals(ECConstants.ZERO) || r.add(k).equals(n));

        // A6
        BigInteger dPlus1ModN = d.add(ECConstants.ONE).modInverse(n);

        s = k.subtract(r.multiply(d)).mod(n);
        s = dPlus1ModN.multiply(s).mod(n);
    } while (s.equals(ECConstants.ZERO));

    // A7
    try {
        ASN1EncodableVector v = new ASN1EncodableVector();
        v.add(new ASN1Integer(r));
        v.add(new ASN1Integer(s));
        return new DERSequence(v).getEncoded(ASN1Encoding.DER);
    } catch (IOException ex) {
        throw new CryptoException("unable to encode signature: " + ex.getMessage(), ex);
    }
}
 

import org.bouncycastle.math.ec.FixedPointCombMultiplier; //导入依赖的package包/类
/**
 * Returns public key point from the given private key.
 */
private static ECPoint publicPointFromPrivate(BigInteger privKey) {
    /*
     * TODO: FixedPointCombMultiplier currently doesn't support scalars longer than the group
     * order, but that could change in future versions.
     */
    if (privKey.bitLength() > CURVE.getN().bitLength()) {
        privKey = privKey.mod(CURVE.getN());
    }
    return new FixedPointCombMultiplier().multiply(CURVE.getG(), privKey);
}
 

import org.bouncycastle.math.ec.FixedPointCombMultiplier; //导入依赖的package包/类
public static Optional<ECCurvePoint> create(BigInteger d, String curveName) {
    X9ECParameters x9ECParameters = ECAssistant.x9ECParameters(curveName);
    ECPoint Q = new FixedPointCombMultiplier().multiply(x9ECParameters.getG(), d).normalize();

    ECCurvePoint point = new ECCurvePoint(Q, curveName, x9ECParameters);
    return Optional.of(point);
}
 

import org.bouncycastle.math.ec.FixedPointCombMultiplier; //导入依赖的package包/类
protected ECMultiplier createBasePointMultiplier()
{
    return new FixedPointCombMultiplier();
}