前言：

RSA属于非对称加密。所谓非对称加密，需要两个密钥：公钥 (publickey) 和私钥 (privatekey)。公钥和私钥是一对，如果用公钥对数据加密，那么只能用对应的私钥解密。如果用私钥对数据加密，只能用对应的公钥进行解密。因为加密和解密用的是不同的密钥，所以称为非对称加密。

废话不多说，上代码

/*** @description: RSA工具类* @author: JuZi* @create: 2023-08-25 10:30:14**/
@Slf4j
@Component
public class RsaUtil {private static final String KEY_ALGORITHM = "RSA";private static final int KEY_SIZE = 2048;//设置长度private static final String PUBLIC_KEY = "publicKey";private static final String PRIVATE_KEY = "privateKey";public static final String SIGNATURE_ALGORITHM = "SHA256withRSA";/*** 生成公、私钥* 根据需要返回String或byte[]类型** @return*/private static Map<String, String> createRSAKeys() {Map<String, String> keyPairMap = new HashMap<>();try {KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance(KEY_ALGORITHM);keyPairGenerator.initialize(KEY_SIZE, new SecureRandom());KeyPair keyPair = keyPairGenerator.generateKeyPair();PublicKey publicKey = keyPair.getPublic();PrivateKey privateKey = keyPair.getPrivate();//获取公、私钥值String publicKeyValue = byte2Base64String(publicKey.getEncoded());String privateKeyValue = byte2Base64String(privateKey.getEncoded());//存入keyPairMap.put(PUBLIC_KEY, publicKeyValue);keyPairMap.put(PRIVATE_KEY, privateKeyValue);} catch (Exception e) {e.printStackTrace();}return keyPairMap;}/*** 通过私钥对参数进行加密** @param Data* @param privateKey* @return*/public static String MakeSign(String Data, String privateKey) {try {byte[] data = Data.getBytes();byte[] keyBytes = base64String2Byte(privateKey);PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);PrivateKey priKey = keyFactory.generatePrivate(pkcs8KeySpec);//这个根据需求填充SHA1WithRSA或SHA256WithRSASignature signature = Signature.getInstance(SIGNATURE_ALGORITHM);signature.initSign(priKey);signature.update(data);return byte2Base64String(signature.sign());} catch (Exception e) {return "";}}/*** 使用公钥** @param Data_ori* @param Singnature* @param publicKeyBase64Str* @return*/public static boolean VeriSign(String Data_ori, String Singnature, String publicKeyBase64Str) {try {byte[] signed = base64String2Byte(Singnature);X509EncodedKeySpec keySpec = new X509EncodedKeySpec(base64String2Byte(publicKeyBase64Str));KeyFactory keyFactory = null;keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);PublicKey publicKey = keyFactory.generatePublic(keySpec);//这个根据需求填充SHA1WithRSA或SHA256WithRSASignature signature = Signature.getInstance(SIGNATURE_ALGORITHM);signature.initVerify(publicKey);signature.update(Data_ori.getBytes(StandardCharsets.UTF_8));return signature.verify(signed);} catch (Exception e) {return false;}}/*** base64字符串转字节数组** @param base64Str* @return*/public static byte[] base64String2Byte(String base64Str) {return Base64.decodeBase64(base64Str);}/*** 字节数组转base64字符串** @param bytes* @return*/public static String byte2Base64String(byte[] bytes) {return new String(new Base64().encode(bytes));}public static byte charToByte(char c) {return (byte) "0123456789ABCDEF".indexOf(c);}
}

工具类全文如上所示，接下来看看效果

测试代码

public static void main(String[] args) throws Exception {log.info("-----开始生成公钥和私钥-----");Map<String, String> keys = createRSAKeys();log.info("-----公钥base64：{}-----", keys.get(PUBLIC_KEY));log.info("-----私钥base64：{}-----", keys.get(PRIVATE_KEY));log.info("-----开始对数据进行加密-----");String data = "hello word ！";log.info("-----源数据：{}-----", data);String sign = RsaUtil.MakeSign(data, keys.get(PRIVATE_KEY));log.info("-----私钥加密结果：{}-----", sign);log.info("-----开始用公钥对私钥的加密验证-----");log.info("-----公钥验证结果：{}-----", VeriSign(data, sign, keys.get(PUBLIC_KEY)));}

测试结果

看起来没问题拿下了。

对逆向感兴趣的盆友可以关注交流，不定时更新常用算法和加密。