import org.spongycastle.jce.spec.ECPrivateKeySpec; //导入依赖的package包/类
@Override
public byte[] getSignature(byte[] data, PrivateKey privateKey) {
    try {
        ECParameterSpec spec = new ECParameterSpec(
            EC_CURVE_PARAMETERS.getCurve(),
            EC_CURVE_PARAMETERS.getG(),
            EC_CURVE_PARAMETERS.getN(),
            EC_CURVE_PARAMETERS.getH(),
            EC_CURVE_PARAMETERS.getSeed()
        );

        BigInteger d = keyToBigInt(privateKey.getPrivateSigningKey());
        KeySpec keySpec = new ECPrivateKeySpec(d, spec);
        java.security.PrivateKey privKey = KeyFactory.getInstance(ALGORITHM_ECDSA, provider)
            .generatePrivate(keySpec);

        Signature sig = Signature.getInstance(ALGORITHM_ECDSA, provider);
        sig.initSign(privKey);
        sig.update(data);
        return sig.sign();
    } catch (GeneralSecurityException e) {
        throw new ApplicationException(e);
    }
}
 

import org.spongycastle.jce.spec.ECPrivateKeySpec; //导入依赖的package包/类
private static PrivateKey privateKeyFromBigInteger(BigInteger priv) {
    if (priv == null) {
        return null;
    } else {
        try {
            return ECKeyFactory
                    .getInstance(SpongyCastleProvider.getInstance())
                    .generatePrivate(new ECPrivateKeySpec(priv, CURVE_SPEC));
        } catch (InvalidKeySpecException ex) {
            throw new AssertionError("Assumed correct key spec statically");
        }
    }
}
 

import org.spongycastle.jce.spec.ECPrivateKeySpec; //导入依赖的package包/类
private static PrivateKey privateKeyFromBigInteger(BigInteger priv) {
    if (priv == null) {
        return null;
    } else {
        try {
            return ECKeyFactory
                .getInstance(SpongyCastleProvider.getInstance())
                .generatePrivate(new ECPrivateKeySpec(priv, CURVE_SPEC));
        } catch (InvalidKeySpecException ex) {
            throw new AssertionError("Assumed correct key spec statically");
        }
    }
}
 

import org.spongycastle.jce.spec.ECPrivateKeySpec; //导入依赖的package包/类
private static PrivateKey privateKeyFromBigInteger(BigInteger priv) {
  if (priv == null) {
    return null;
  } else {
    try {
      return ECKeyFactory.getInstance(SpongyCastleProvider.getInstance())
          .generatePrivate(new ECPrivateKeySpec(priv, CURVE_SPEC));
    } catch (InvalidKeySpecException ex) {
      throw new AssertionError("Assumed correct key spec statically");
    }
  }
}
 

import org.spongycastle.jce.spec.ECPrivateKeySpec; //导入依赖的package包/类
private PrivateKey loadPrivateKey(byte[] data) throws InvalidKeySpecException  {
    ECPrivateKeySpec prvkey = new ECPrivateKeySpec(new BigInteger(1, data), params);
    return kf.generatePrivate(prvkey);
}