content: package cn.org.alan.exam.utils;
  
  
  
  import cn.org.alan.exam.utils.CryptoUtils.Algorithm.Encryption;
  import cn.org.alan.exam.utils.CryptoUtils.Algorithm.Signing;
  import com.baomidou.mybatisplus.core.toolkit.StringUtils;
  import lombok.AllArgsConstructor;
  import lombok.Data;
  import lombok.Getter;
  import lombok.NoArgsConstructor;
  import org.springframework.stereotype.Component;
  
  
  import javax.crypto.Cipher;
  import javax.crypto.KeyGenerator;
  import javax.crypto.NoSuchPaddingException;
  import javax.crypto.SecretKey;
  import javax.crypto.spec.IvParameterSpec;
  import javax.crypto.spec.SecretKeySpec;
  import java.nio.charset.Charset;
  import java.nio.charset.StandardCharsets;
  import java.security.Key;
  import java.security.KeyFactory;
  import java.security.KeyPair;
  import java.security.KeyPairGenerator;
  import java.security.NoSuchAlgorithmException;
  import java.security.PrivateKey;
  import java.security.PublicKey;
  import java.security.Signature;
  import java.security.spec.InvalidKeySpecException;
  import java.security.spec.KeySpec;
  import java.security.spec.PKCS8EncodedKeySpec;
  import java.security.spec.X509EncodedKeySpec;
  import java.util.Base64;
  import java.util.Base64.Decoder;
  import java.util.Base64.Encoder;
  import java.util.HashMap;
  import java.util.Map;
  import java.util.concurrent.ConcurrentHashMap;
  
  /**
   * 安全类工具类
   * 支持AES、DES、RSA加密、数字签名以及生成对称密钥和非对称密钥对
   *
   * @Author Alan
   * @Version
   * @Date 2024/6/8 10:41 AM
   */
  @Component
  public class CryptoUtils {
  
      private static final Charset DEFAULT_CHARSET = StandardCharsets.UTF_8;
      private static final Encoder BASE64_ENCODER = Base64.getEncoder();
      private static final Decoder BASE64_DECODER = Base64.getDecoder();
  
      private static final Map<Algorithm, KeyFactory> KEY_FACTORY_CACHE = new ConcurrentHashMap<>();
      private static final Map<Algorithm, Cipher> CIPHER_CACHE = new HashMap<>();
  
      /**
       * 生成对称密钥，目前支持的算法有AES、DES
       * @param algorithm
       * @return
       * @throws NoSuchAlgorithmException
       */
      public static String generateSymmetricKey(Algorithm algorithm) throws NoSuchAlgorithmException {
          KeyGenerator generator = KeyGenerator.getInstance(algorithm.getName());
          generator.init(algorithm.getKeySize());
          SecretKey secretKey = generator.generateKey();
          return BASE64_ENCODER.encodeToString(secretKey.getEncoded());
      }
  
      /**
       * 生成非对称密钥对，目前支持的算法有RSA、DSA。备注：默认生成的密钥格式为PKCS8
       * @param algorithm
       * @return
       * @throws NoSuchAlgorithmException
       */
      public static AsymmetricKeyPair generateAsymmetricKeyPair(Algorithm algorithm) throws NoSuchAlgorithmException {
          KeyPairGenerator generator = KeyPairGenerator.getInstance(algorithm.getName());
          generator.initialize(algorithm.getKeySize());
          KeyPair keyPair = generator.generateKeyPair();
          String publicKey = BASE64_ENCODER.encodeToString(keyPair.getPublic().getEncoded());
          String privateKey = BASE64_ENCODER.encodeToString(keyPair.getPrivate().getEncoded());
          return new AsymmetricKeyPair(publicKey, privateKey);
      }
  
      public static String encryptByRSA(String publicKeyText, String plainText) throws Exception {
          return encryptAsymmetrically(publicKeyText, plainText, Encryption.RSA_ECB_PKCS1);
      }
  
      public static String decryptByRSA(String privateKeyText, String ciphertext) throws Exception {
          return decryptAsymmetrically(privateKeyText, ciphertext, Encryption.RSA_ECB_PKCS1);
      }
  
      /**
       * SHA1签名算法和DSA加密算法结合使用生成数字签名
       * @param privateKeyText
       * @param msg
       * @return 数字签名
       * @throws Exception
       */
      public static String signBySHA1WithDSA(String privateKeyText, String msg) throws Exception {
          return doSign(privateKeyText, msg, Encryption.DSA, Signing.SHA1WithDSA);
      }
  
      /**
       * SHA1签名算法和RSA加密算法结合使用生成数字签名
       * @param privateKeyText 私钥
       * @param msg 待加签内容
       * @return 数字签名
       * @throws Exception
       */
      public static String signBySHA1WithRSA(String privateKeyText, String msg) throws Exception {
          return doSign(privateKeyText, msg, Encryption.RSA_ECB_PKCS1, Signing.SHA1WithRSA);
      }
  
      /**
       * SHA256签名算法和RSA加密算法结合使用生成数字签名
       * @param privateKeyText 私钥
       * @param msg 待加签内容
       * @return 数字签名
       * @throws Exception
       */
      public static String signBySHA256WithRSA(String privateKeyText, String msg) throws Exception {
          return doSign(privateKeyText, msg, Encryption.RSA_ECB_PKCS1, Signing.SHA256WithRSA);
      }
  
      /**
       * SHA1签名算法和DSA加密算法检验数字签名
       * @param publicKeyText 公钥
       * @param msg 待验签内容
       * @param signatureText 数字
       * @return 检验是否成功
       * @throws Exception
       */
      public static boolean verifyBySHA1WithDSA(String publicKeyText, String msg, String signatureText) throws Exception {
          return doVerify(publicKeyText, msg, signatureText, Encryption.DSA, Signing.SHA1WithDSA);
      }
  
      /**
       * SHA1签名算法和RSA加密算法检验数字签名
       * @param publicKeyText 公钥
       * @param msg 待验签内容
       * @param signatureText 签名
       * @return 校验是否成功
       * @throws Exception
       */
      public static boolean verifyBySHA1WithRSA(String publicKeyText, String msg, String signatureText) throws Exception {
          return doVerify(publicKeyText, msg, signatureText, Encryption.RSA_ECB_PKCS1, Signing.SHA1WithRSA);
      }
  
      /**
       * SHA256签名算法和RSA加密算法检验数字签名
       * @param publicKeyText 公钥
       * @param msg 待验签内容
       * @param signatureText 签名
       * @return 校验是否成功
       * @throws Exception
       */
      public static boolean verifyBySHA256WithRSA(String publicKeyText, String msg, String signatureText) throws Exception {
          return doVerify(publicKeyText, msg, signatureText, Encryption.RSA_ECB_PKCS1, Signing.SHA256WithRSA);
      }
  
      /**
       * 对称加密
       * @param secretKey 密钥
       * @param iv 加密向量，只有CBC模式才支持，如果是CBC则必传
       * @param plainText 明文
       * @param algorithm 对称加密算法，如AES、DES
       * @return
       * @throws Exception
       */
      public static String encryptSymmetrically(String secretKey, String iv, String plainText, Algorithm algorithm) throws Exception {
          SecretKey key = decodeSymmetricKey(secretKey, algorithm);
          IvParameterSpec ivParameterSpec = StringUtils.isBlank(iv) ? null : decodeIv(iv);
          byte[] plainTextInBytes = plainText.getBytes(DEFAULT_CHARSET);
          byte[] ciphertextInBytes = transform(algorithm, Cipher.ENCRYPT_MODE, key, ivParameterSpec, plainTextInBytes);
  
          return BASE64_ENCODER.encodeToString(ciphertextInBytes);
      }
  
      /**
       * 对称解密
       * @param secretKey 密钥
       * @param iv 加密向量，只有CBC模式才支持，如果是CBC则必传
       * @param ciphertext 密文
       * @param algorithm 对称加密算法，如AES、DES
       * @return
       * @throws Exception
       */
      public static String decryptSymmetrically(String secretKey, String iv, String ciphertext, Algorithm algorithm) throws Exception {
          SecretKey key = decodeSymmetricKey(secretKey, algorithm);
          IvParameterSpec ivParameterSpec = StringUtils.isBlank(iv) ? null : decodeIv(iv);
          byte[] ciphertextInBytes = BASE64_DECODER.decode(ciphertext);
          byte[] plainTextInBytes = transform(algorithm, Cipher.DECRYPT_MODE, key, ivParameterSpec, ciphertextInBytes);
          return new String(plainTextInBytes, DEFAULT_CHARSET);
      }
  
      /**
       * 非对称加密
       * @param publicKeyText 公钥
       * @param plainText 明文
       * @param algorithm 非对称加密算法
       * @return
       * @throws Exception
       */
      public static String encryptAsymmetrically(String publicKeyText, String plainText, Algorithm algorithm) throws Exception {
          PublicKey publicKey = regeneratePublicKey(publicKeyText, algorithm);
          byte[] plainTextInBytes = plainText.getBytes(DEFAULT_CHARSET);
          byte[] ciphertextInBytes = transform(algorithm, Cipher.ENCRYPT_MODE, publicKey, plainTextInBytes);
          return BASE64_ENCODER.encodeToString(ciphertextInBytes);
      }
  
      /**
       * 非对称解密
       * @param privateKeyText 私钥
       * @param ciphertext 密文
       * @param algorithm 非对称加密算法
       * @return
       * @throws Exception
       */
      public static String decryptAsymmetrically(String privateKeyText, String ciphertext, Algorithm algorithm) throws Exception {
          PrivateKey privateKey = regeneratePrivateKey(privateKeyText, algorithm);
          byte[] ciphertextInBytes = BASE64_DECODER.decode(ciphertext);
          byte[] plainTextInBytes = transform(algorithm, Cipher.DECRYPT_MODE, privateKey, ciphertextInBytes);
          return new String(plainTextInBytes, DEFAULT_CHARSET);
      }
  
      /**
       * 生成数字签名
       * @param privateKeyText 私钥
       * @param msg 传输的数据
       * @param encryptionAlgorithm 加密算法，见Algorithm中的加密算法
       * @param signatureAlgorithm 签名算法，见Algorithm中的签名算法
       * @return 数字签名
       * @throws Exception
       */
      public static String doSign(String privateKeyText, String msg, Algorithm encryptionAlgorithm, Algorithm signatureAlgorithm)
              throws Exception {
          PrivateKey privateKey = regeneratePrivateKey(privateKeyText, encryptionAlgorithm);
          // Signature只支持签名算法
          Signature signature = Signature.getInstance(signatureAlgorithm.getName());
          signature.initSign(privateKey);
          signature.update(msg.getBytes(DEFAULT_CHARSET));
          byte[] signatureInBytes = signature.sign();
          return BASE64_ENCODER.encodeToString(signatureInBytes);
      }
  
      /**
       * 数字签名验证
       * @param publicKeyText 公钥
       * @param msg 传输的数据
       * @param signatureText 数字签名
       * @param encryptionAlgorithm 加密算法，见Algorithm中的加密算法
       * @param signatureAlgorithm 签名算法，见Algorithm中的签名算法
       * @return 校验是否成功
       * @throws Exception
       */
      public static boolean doVerify(String publicKeyText, String msg, String signatureText, Algorithm encryptionAlgorithm,
                                     Algorithm signatureAlgorithm) throws Exception {
          PublicKey publicKey = regeneratePublicKey(publicKeyText, encryptionAlgorithm);
          Signature signature = Signature.getInstance(signatureAlgorithm.getName());
          signature.initVerify(publicKey);
          signature.update(msg.getBytes(DEFAULT_CHARSET));
          return signature.verify(BASE64_DECODER.decode(signatureText));
      }
  
      /**
       * 将密钥进行Base64位解码，重新生成SecretKey实例
       * @param secretKey 密钥
       * @param algorithm 算法
       * @return
       */
      private static SecretKey decodeSymmetricKey(String secretKey, Algorithm algorithm) {
          byte[] key = BASE64_DECODER.decode(secretKey);
          return new SecretKeySpec(key, algorithm.getName());
      }
  
      private static IvParameterSpec decodeIv(String iv) {
          byte[] ivInBytes = BASE64_DECODER.decode(iv);
          return new IvParameterSpec(ivInBytes);
      }
  
      private static PublicKey regeneratePublicKey(String publicKeyText, Algorithm algorithm)
              throws NoSuchAlgorithmException, InvalidKeySpecException {
          byte[] keyInBytes = BASE64_DECODER.decode(publicKeyText);
          KeyFactory keyFactory = getKeyFactory(algorithm);
          // 公钥必须使用RSAPublicKeySpec或者X509EncodedKeySpec
          KeySpec publicKeySpec = new X509EncodedKeySpec(keyInBytes);
          PublicKey publicKey = keyFactory.generatePublic(publicKeySpec);
          return publicKey;
      }
  
      private static PrivateKey regeneratePrivateKey(String key, Algorithm algorithm) throws Exception {
          byte[] keyInBytes = BASE64_DECODER.decode(key);
          KeyFactory keyFactory = getKeyFactory(algorithm);
          // 私钥必须使用RSAPrivateCrtKeySpec或者PKCS8EncodedKeySpec
          KeySpec privateKeySpec = new PKCS8EncodedKeySpec(keyInBytes);
          PrivateKey privateKey = keyFactory.generatePrivate(privateKeySpec);
          return privateKey;
      }
  
      private static KeyFactory getKeyFactory(Algorithm algorithm) throws NoSuchAlgorithmException {
          KeyFactory keyFactory = KEY_FACTORY_CACHE.get(algorithm);
          if (keyFactory == null) {
              keyFactory = KeyFactory.getInstance(algorithm.getName());
              KEY_FACTORY_CACHE.put(algorithm, keyFactory);
          }
  
          return keyFactory;
      }
  
      private static byte[] transform(Algorithm algorithm, int mode, Key key, byte[] msg) throws Exception {
          return transform(algorithm, mode, key, null, msg);
      }
  
      private static byte[] transform(Algorithm algorithm, int mode, Key key, IvParameterSpec iv, byte[] msg) throws Exception {
          Cipher cipher = CIPHER_CACHE.get(algorithm);
          // double check，减少上下文切换
          if (cipher == null) {
              synchronized (CryptoUtils.class) {
                  if ((cipher = CIPHER_CACHE.get(algorithm)) == null) {
                      cipher = determineWhichCipherToUse(algorithm);
                      CIPHER_CACHE.put(algorithm, cipher);
                  }
                  cipher.init(mode, key, iv);
                  return cipher.doFinal(msg);
              }
          }
  
          synchronized (CryptoUtils.class) {
              cipher.init(mode, key, iv);
              return cipher.doFinal(msg);
          }
      }
  
      private static Cipher determineWhichCipherToUse(Algorithm algorithm) throws NoSuchAlgorithmException, NoSuchPaddingException {
          Cipher cipher;
          String transformation = algorithm.getTransformation();
          // 官方推荐的transformation使用algorithm/mode/padding组合，SunJCE使用ECB作为默认模式，使用PKCS5Padding作为默认填充
          if (StringUtils.isNotEmpty(transformation)) {
              cipher = Cipher.getInstance(transformation);
          } else {
              cipher = Cipher.getInstance(algorithm.getName());
          }
  
          return cipher;
      }
  
      /**
       * 算法分为加密算法和签名算法，更多算法实现见：<br/>
       * <a href="https://docs.oracle.com/javase/8/docs/technotes/guides/security/StandardNames.html#impl">jdk8中的标准算法</a>
       */
      public static class Algorithm {
  
          public interface Encryption {
              Algorithm AES_ECB_PKCS5 = new Algorithm("AES", "AES/ECB/PKCS5Padding", 128);
              Algorithm AES_CBC_PKCS5 = new Algorithm("AES", "AES/CBC/PKCS5Padding", 128);
              Algorithm DES_ECB_PKCS5 = new Algorithm("DES", "DES/ECB/PKCS5Padding", 56);
              Algorithm DES_CBC_PKCS5 = new Algorithm("DES", "DES/CBC/PKCS5Padding", 56);
              Algorithm RSA_ECB_PKCS1 = new Algorithm("RSA", "RSA/ECB/PKCS1Padding", 1024);
              Algorithm DSA = new Algorithm("DSA", 1024);
          }
  
          public interface Signing {
              Algorithm SHA1WithDSA = new Algorithm("SHA1withDSA", 1024);
              Algorithm SHA1WithRSA = new Algorithm("SHA1WithRSA", 2048);
              Algorithm SHA256WithRSA = new Algorithm("SHA256WithRSA", 2048);
          }
  
          @Getter
          private String name;
          @Getter
          private String transformation;
          @Getter
          private int keySize;
  
          public Algorithm(String name, int keySize) {
              this(name, null, keySize);
          }
  
          public Algorithm(String name, String transformation, int keySize) {
              this.name = name;
              this.transformation = transformation;
              this.keySize = keySize;
          }
  
      }
  
      @Data
      @NoArgsConstructor
      @AllArgsConstructor
      public static class AsymmetricKeyPair {
  
          private String publicKey;
          private String privateKey;
      }
  
  }
  
  
  