始于我工作中的一个需求，在网上很少找到资料所以来写一下

字符串公钥

公钥是对接方给的，是一个长字符串类似于这种格式

工具类中也有生成公私钥的方法，我测试加解密也能成功

秘钥生成借鉴的是这个文章的内容
https://blog.csdn.net/Kevin_zhai/article/details/109351247

SM2加解密工具类

加解密的方法初版忘了是在哪借鉴的了见谅，初版是直接用PublicKey 和 PrivateKey 对象加解密的，我把它改为用字符串转为公钥和私钥的方式加解密。

加密方法因为需求是要返回加密后的base64字符串，本来是直接转为字符串返回的，后来又改为这样的，同样的解密的时候也改了先用base64解码，根据需求自己调一下吧。

package com.encrypt.utils.sm2;import lombok.extern.slf4j.Slf4j;
import org.apache.commons.codec.binary.Base64;
import org.bouncycastle.crypto.engines.SM2Engine;
import org.bouncycastle.crypto.params.ECDomainParameters;
import org.bouncycastle.crypto.params.ECPrivateKeyParameters;
import org.bouncycastle.crypto.params.ECPublicKeyParameters;
import org.bouncycastle.crypto.params.ParametersWithRandom;
import org.bouncycastle.jcajce.provider.asymmetric.ec.BCECPrivateKey;
import org.bouncycastle.jcajce.provider.asymmetric.ec.BCECPublicKey;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.bouncycastle.jce.spec.ECParameterSpec;
import sun.misc.BASE64Decoder;import java.security.*;
import java.security.spec.ECGenParameterSpec;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;/*** @ClassName SM2Util* @Description //TODO* @Date 2022/2/18* @Author yangy* @Version 1.0**/
@Slf4j
public class SM2Util {/*** SM2加密算法* @param publicKeyStr     公钥* @param data          明文数据* @return*/public static String encrypt(String publicKeyStr, String data){Security.addProvider(new BouncyCastleProvider());PublicKey publicKey = null;try {log.info("开始转换字符串公钥，公钥值：{},数据值:{}",publicKeyStr,data);byte[] keyBytes;keyBytes = (new BASE64Decoder()).decodeBuffer(publicKeyStr);KeyFactory keyFactory = KeyFactory.getInstance("EC", BouncyCastleProvider.PROVIDER_NAME);X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);publicKey = keyFactory.generatePublic(keySpec);log.info("转换后的公钥：{}",publicKey);} catch (Exception e) {log.error("SM2字符串公钥转换异常：{}",e.getMessage());e.printStackTrace();}log.info("SM2开始加密数据");ECPublicKeyParameters ecPublicKeyParameters = null;if (publicKey instanceof BCECPublicKey) {BCECPublicKey bcecPublicKey = (BCECPublicKey) publicKey;ECParameterSpec ecParameterSpec = bcecPublicKey.getParameters();ECDomainParameters ecDomainParameters = new ECDomainParameters(ecParameterSpec.getCurve(),ecParameterSpec.getG(), ecParameterSpec.getN());ecPublicKeyParameters = new ECPublicKeyParameters(bcecPublicKey.getQ(), ecDomainParameters);}SM2Engine sm2Engine = new SM2Engine();sm2Engine.init(true, new ParametersWithRandom(ecPublicKeyParameters, new SecureRandom()));byte[] arrayOfBytes = null;try {byte[] in = data.getBytes("utf-8");arrayOfBytes = sm2Engine.processBlock(in,0, in.length);} catch (Exception e) {log.error("SM2加密时出现异常:",e.getMessage());System.out.println("SM2加密时出现异常:");}return  Base64.encodeBase64String(arrayOfBytes);}/*** SM2解密算法* @param privateKeyStr        私钥* @param cipherData        密文数据* @return*/public static String decrypt(String privateKeyStr, String cipherData){PrivateKey privateKey = null;byte[] keyBytes;try {keyBytes = (new BASE64Decoder()).decodeBuffer(privateKeyStr);KeyFactory keyFactory = KeyFactory.getInstance("EC", BouncyCastleProvider.PROVIDER_NAME);PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(keyBytes);privateKey=keyFactory.generatePrivate(keySpec);}catch (Exception e){log.error("SM2字符串私钥转换异常：{}",e.getMessage());e.printStackTrace();}BCECPrivateKey bcecPrivateKey = (BCECPrivateKey) privateKey;ECParameterSpec ecParameterSpec = bcecPrivateKey.getParameters();ECDomainParameters ecDomainParameters = new ECDomainParameters(ecParameterSpec.getCurve(),ecParameterSpec.getG(), ecParameterSpec.getN());ECPrivateKeyParameters ecPrivateKeyParameters = new ECPrivateKeyParameters(bcecPrivateKey.getD(),ecDomainParameters);SM2Engine sm2Engine = new SM2Engine();sm2Engine.init(false, ecPrivateKeyParameters);String result = null;byte[] arrayOfBytes = null;try {byte[] in = Base64.decodeBase64(cipherData);arrayOfBytes = sm2Engine.processBlock(in,0, in.length);result=new String(arrayOfBytes, "utf-8");} catch (Exception e) {System.out.println("SM2解密时出现异常");}return result;}/*** SM2算法生成密钥对* @return 密钥对信息*/public static KeyPair generateSm2KeyPair() {try {final ECGenParameterSpec sm2Spec = new ECGenParameterSpec("sm2p256v1");// 获取一个椭圆曲线类型的密钥对生成器final KeyPairGenerator kpg = KeyPairGenerator.getInstance("EC", new BouncyCastleProvider());SecureRandom random = new SecureRandom();// 使用SM2的算法区域初始化密钥生成器kpg.initialize(sm2Spec, random);// 获取密钥对KeyPair keyPair = kpg.generateKeyPair();return keyPair;} catch (Exception e) {log.error("generate sm2 key pair failed:{}", e.getMessage(), e);return null;}}
}/*** main 方法测试**/public static void main(String[] args) {KeyPair keyPair = SM2Util.generateSm2KeyPair();String privateKey = Base64.encodeBase64String(keyPair.getPrivate().getEncoded());String publicKey  = Base64.encodeBase64String(keyPair.getPublic().getEncoded());System.out.println("公钥："+publicKey);System.out.println("私钥："+privateKey);String data="123456";String encrypt = SM2Util.encrypt(publicKey,data);String decrypt = SM2Util.decrypt(privateKey, encrypt);System.out.println("加密后数据："+encrypt);System.out.println("解密后数据："+decrypt);}