sm2 java

您好！关于 Java 实现 SM2 算法，您可以使用 Bouncy Castle 加密库的 SM2 类。以下是一个简单的示例代码，用于生成 SM2 密钥对、加密、解密、签名和验签操作：

import org.bouncycastle.crypto.AsymmetricCipherKeyPair;
import org.bouncycastle.crypto.engines.SM2Engine;
import org.bouncycastle.crypto.generators.ECKeyPairGenerator;
import org.bouncycastle.crypto.params.*;
import org.bouncycastle.crypto.signers.SM2Signer;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.bouncycastle.util.encoders.Hex;

import java.security.Security;

public class SM2Demo {
    static {
        Security.addProvider(new BouncyCastleProvider());
    }

    public static void main(String[] args) throws Exception {
        // 生成密钥对
        ECKeyPairGenerator kpg = new ECKeyPairGenerator();
        kpg.init(new ECKeyGenerationParameters(
                new ECGenParameterSpec("sm2p256v1"), new SecureRandom()));
        AsymmetricCipherKeyPair kp = kpg.generateKeyPair();
        ECPrivateKeyParameters privateKey = (ECPrivateKeyParameters) kp.getPrivate();
        ECPublicKeyParameters publicKey = (ECPublicKeyParameters) kp.getPublic();

        // 消息明文
        String message = "hello world";
        byte[] msg = message.getBytes();

        // 加密
        SM2Engine engine = new SM2Engine();
        ParametersWithRandom pwr = new ParametersWithRandom(publicKey, new SecureRandom());
        engine.init(true, pwr);
        byte[] ciphertext = engine.processBlock(msg, 0, msg.length);

        // 解密
        engine.init(false, privateKey);
        byte[] plaintext = engine.processBlock(ciphertext, 0, ciphertext.length);
        System.out.println("解密后明文：" + new String(plaintext));

        // 签名
        SM2Signer signer = new SM2Signer();
        signer.init(true, privateKey);
        signer.update(msg, 0, msg.length);
        byte[] signature = signer.generateSignature();

        // 验签
        signer.init(false, publicKey);
        signer.update(msg, 0, msg.length);
        boolean result = signer.verifySignature(signature);
        System.out.println("验签结果：" + result);
    }
}

请注意，Bouncy Castle 加密库需要在您的项目中添加依赖，可以从其官网下载并添加到您的项目中。此外，以上代码仅为示例，实际应用中需要根据具体情况进行修改和完善。