java SM2Cipher

Java中的SM2Cipher是一种实现SM2椭圆曲线加密算法的类。SM2是一种国密标准，用于数字签名和加密。以下是一个简单的SM2Cipher类示例：

import org.bouncycastle.crypto.engines.SM2Engine;
import org.bouncycastle.crypto.params.ECPrivateKeyParameters;
import org.bouncycastle.crypto.params.ECPublicKeyParameters;
import org.bouncycastle.crypto.params.ParametersWithRandom;
import org.bouncycastle.crypto.util.PrivateKeyFactory;
import org.bouncycastle.crypto.util.PublicKeyFactory;
import org.bouncycastle.math.ec.ECPoint;

import java.security.SecureRandom;

public class SM2Cipher {
    private byte[] publicKey;
    private byte[] privateKey;
    private SecureRandom random;

    public SM2Cipher() {
        random = new SecureRandom();
    }

    public void setPublicKey(byte[] publicKey) {
        this.publicKey = publicKey;
    }

    public void setPrivateKey(byte[] privateKey) {
        this.privateKey = privateKey;
    }

    public byte[] encrypt(byte[] data) {
        try {
            ECPublicKeyParameters publicKeyParam = (ECPublicKeyParameters) PublicKeyFactory.createKey(publicKey);
            ParametersWithRandom params = new ParametersWithRandom(publicKeyParam, random);
            SM2Engine engine = new SM2Engine();
            engine.init(true, params);
            return engine.processBlock(data, 0, data.length);
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

    public byte[] decrypt(byte[] data) {
        try {
            ECPrivateKeyParameters privateKeyParam = (ECPrivateKeyParameters) PrivateKeyFactory.createKey(privateKey);
            SM2Engine engine = new SM2Engine();
            engine.init(false, privateKeyParam);
            return engine.processBlock(data, 0, data.length);
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

    public ECPoint createPoint(String xHex, String yHex) {
        return SM2Util.createPoint(xHex, yHex);
    }
}

在这个例子中，SM2Cipher类提供了加密和解密方法，以及创建椭圆曲线点的方法。它使用bouncycastle库来实现SM2算法。加密和解密方法都需要设置公钥和私钥，这里只提供了简单的字节数组设置方法。createPoint方法使用SM2Util类来创建椭圆曲线点。