package com.test;

import org.bouncycastle.asn1.x9.X9ECParameters;
import org.bouncycastle.crypto.ec.CustomNamedCurves;
import org.bouncycastle.jcajce.provider.asymmetric.ec.BCECPublicKey;
import org.bouncycastle.jce.ECNamedCurveTable;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.bouncycastle.jce.spec.ECNamedCurveParameterSpec;
import org.bouncycastle.jce.spec.ECNamedCurveSpec;

import java.math.BigInteger;
import java.security.KeyFactory;
import java.security.NoSuchAlgorithmException;
import java.security.interfaces.ECPublicKey;
import java.security.spec.ECPoint;
import java.security.spec.ECPublicKeySpec;

public class KeyTest {
    public static ECPublicKey hexToSM2PublicKey(String x, String y) {
        ECPublicKey pubkey = null;
        try {
            KeyFactory keyFactory = KeyFactory.getInstance("EC");
            ECPoint ecPoint = new ECPoint(
                    new BigInteger(x, 16), new BigInteger(y, 16));

            ECNamedCurveParameterSpec parameterSpec = ECNamedCurveTable.getParameterSpec("sm2p256v1");
            ECNamedCurveSpec spec = new ECNamedCurveSpec("sm2p256v1", parameterSpec.getCurve(), parameterSpec.getG(), parameterSpec.getN(), parameterSpec.getH(), parameterSpec.getSeed());

            ECPublicKeySpec keySpec = new ECPublicKeySpec(ecPoint, spec);
            pubkey = new BCECPublicKey("BC", keySpec, BouncyCastleProvider.CONFIGURATION);
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }

        return pubkey;
    }

    public static void main(String[] args){
        ECPublicKey pubkey = hexToSM2PublicKey(
                "09F9DF311E5421A150DD7D161E4BC5C672179FAD1833FC076BB08FF356F35020",
                "CCEA490CE26775A52DC6EA718CC1AA600AED05FBF35E084A6632F6072DA9AD13"
        );

        System.out.println(pubkey.getW().getAffineX().toString(16));
        System.out.println(pubkey.getW().getAffineY().toString(16));
    }
}