sm2加密java怎么写

SM2加密算法是一种国密算法，适用于非对称加密和数字签名，其Java实现方式如下：

1. 导入相关库文件

import org.bouncycastle.crypto.AsymmetricCipherKeyPair;
import org.bouncycastle.crypto.engines.SM2Engine;
import org.bouncycastle.crypto.generators.AsymmetricKeyPairGenerator;
import org.bouncycastle.crypto.params.ECPrivateKeyParameters;
import org.bouncycastle.crypto.params.ECPublicKeyParameters;
import org.bouncycastle.crypto.params.ParametersWithRandom;
import org.bouncycastle.crypto.signers.SM2Signer;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.bouncycastle.math.ec.ECPoint;

import java.security.Security;

2. 初始化安全提供程序

// 初始化安全提供程序
Security.addProvider(new BouncyCastleProvider());

3. 生成SM2密钥对

// 生成SM2密钥对
AsymmetricKeyPairGenerator keyPairGenerator = new SM2KeyPairGenerator();
SecureRandom random = new SecureRandom();
keyPairGenerator.init(new SM2KeyGenerationParameters(random));
AsymmetricCipherKeyPair keyPair = keyPairGenerator.generateKeyPair();
ECPrivateKeyParameters privateKey = (ECPrivateKeyParameters) keyPair.getPrivate();
ECPublicKeyParameters publicKey = (ECPublicKeyParameters) keyPair.getPublic();

4. SM2加密

// SM2加密
SM2Engine engine = new SM2Engine();
engine.init(true, new ParametersWithRandom(publicKey, random));
byte[] encryptData = engine.processBlock(data, 0, data.length);

5. SM2解密

// SM2解密
engine.init(false, privateKey);
byte[] decryptData = engine.processBlock(encryptData, 0, encryptData.length);

6. SM2签名

// SM2签名
SM2Signer signer = new SM2Signer();
signer.init(true, privateKey);
signer.update(data, 0, data.length);
byte[] signature = signer.generateSignature();

7. SM2验签

// SM2验签
signer.init(false, publicKey);
signer.update(data, 0, data.length);
boolean verifyResult = signer.verifySignature(signature);

以上是SM2加密算法的Java实现方式，需要注意的是，SM2算法在加密和签名时需要使用相应的密钥对，因此需要事先生成SM2密钥对。