rsa简单使用

古城微笑少年丶 2022-05-09 13:26 405阅读 0赞

RSAUtils.java

public final class RSAUtils { 
    
       /** 安全服务提供者 */
       private static final Provider PROVIDER = new BouncyCastleProvider();
    
       /** 密钥大小 */
       private static final int KEY_SIZE = 2048;
       
       private static List<KeyPair> keys = new ArrayList<KeyPair>();
       
       private static int MAX_KEYS = 500;//最大公钥数量
       
       /** * 不可实例化 */
       private RSAUtils() { 
       }
    
       /** * 生成密钥对 * * @return 密钥对 */
       private static KeyPair getNewKeyPair() { 
          try { 
    	//密钥生成器
             KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA", PROVIDER);
    	//初始化密钥生成器
             keyPairGenerator.initialize(KEY_SIZE, new SecureRandom());
    	//返回生成的密钥
             return keyPairGenerator.generateKeyPair();
          } catch (NoSuchAlgorithmException e) { 
             e.printStackTrace();
             return null;
          }
       }
    
       public static KeyPair generateKeyPair() { 
          //若达到最大公钥数量，从当前公钥库返回一个，否则生成新公钥并返回
          if(keys.size()>MAX_KEYS){ 
             return keys.get((int)(System.currentTimeMillis()%keys.size()));
          }else{ 
    // keys.get(-1);
             KeyPair key = getNewKeyPair();
             keys.add(key);
             //System.out.println("生成密钥成功，当前密钥库"+keys.size());
             return key;
          }
       }
    
    	
    /** * 加密 * * @param publicKey * 公钥 * @param data * 数据 * @return 加密后的数据 */
    public static byte[] encrypt(PublicKey publicKey, byte[] data) { 
       Assert.notNull(publicKey);
       Assert.notNull(data);
       try { 
    	//RSA密码器实例
          Cipher cipher = Cipher.getInstance("RSA", PROVIDER);
    	//初始化密码器为加密模式
          cipher.init(Cipher.ENCRYPT_MODE, publicKey);
          return cipher.doFinal(data);
       } catch (Exception e) { 
          e.printStackTrace();
          return null;
       }
    }
    /** * 解密 * * @param privateKey * 私钥 * @param data * 数据 * @return 解密后的数据 */
    public static byte[] decrypt(PrivateKey privateKey, byte[] data) { 
       Assert.notNull(privateKey);
       Assert.notNull(data);
       try { 
    	//生成密码器实例（填充模式）
          Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding", PROVIDER);
    	//初始化密码器为加密模式
          cipher.init(Cipher.DECRYPT_MODE, privateKey);
          return cipher.doFinal(data);
       } catch (Exception e) { 
          return null;
       }
    }
    }

RSAServiceImpl.java

@Service("rsaServiceImpl")
    public class RSAServiceImpl implements RSAService { 
    
       /** "私钥"参数名称 */
       private static final String PRIVATE_KEY_ATTRIBUTE_NAME = "privateKey";
    
       @Transactional(readOnly = true)
       public RSAPublicKey generateKey(HttpServletRequest request) { 
          Assert.notNull(request);
    	//生成密钥
          KeyPair keyPair = RSAUtils.generateKeyPair();
    	//获取公钥
          RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
    	//获取私钥
          RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
    	//私钥设置在Session中
          HttpSession session = request.getSession();
          session.setAttribute(PRIVATE_KEY_ATTRIBUTE_NAME, privateKey);
    	//公钥返回前端页面，并用其对明文进行加密
          return publicKey;
       }
    
       @Transactional(readOnly = true)
       public String decryptParameter(String name, HttpServletRequest request) { 
          Assert.notNull(request);
          if (name != null) { 
    	//获取Session中的私钥
             HttpSession session = request.getSession();
             RSAPrivateKey privateKey = (RSAPrivateKey) session.getAttribute(PRIVATE_KEY_ATTRIBUTE_NAME);
    	//获取密文
             String parameter = request.getParameter(name);
             if (privateKey != null && StringUtils.isNotEmpty(parameter)) { 
    		//用密钥对密文进行解密
                return RSAUtils.decrypt(privateKey, parameter);
             }
          }
          return null;
       }
    }