RSA加密的使用（前后端）

公钥（publicKey）加密、私钥（privateKey）解密。不能逆向，私钥（privateKey）加密、公钥（publicKey）解密。说白了就是前后端都需要用公钥（publicKey）进行加密，用私钥（privateKey）进行解密。

引入前端 JS 库：jsencrypt.js

npm install jsencrypt 

使用

后端生成RSAUtil工具类

public class RSAUtil {
	static {
		Security.addProvider(new BouncyCastleProvider());
	}
	    /**
     * 随机生成密钥对
     *
     * @param filePath 密钥对要存储的路径
     */
    public static void genKeyPair(String filePath) {
		// KeyPairGenerator类用于生成公钥和私钥对，基于RSA算法生成对象
		KeyPairGenerator keyPairGen = null;
		try {
			keyPairGen = KeyPairGenerator.getInstance("RSA");
		} catch (NoSuchAlgorithmException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		// 初始化密钥对生成器，密钥大小为96-1024位
		keyPairGen.initialize(1024, new SecureRandom());
		// 生成一个密钥对，保存在keyPair中
		KeyPair keyPair = keyPairGen.generateKeyPair();
		// 得到私钥
		RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
		// 得到公钥
		RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
		try {
			// 得到公钥字符串
			String publicKeyString = Base64.getEncoder().encodeToString(publicKey.getEncoded());
			// 得到私钥字符串
			String privateKeyString = Base64.getEncoder().encodeToString(privateKey.getEncoded());
			// 将密钥对写入到文件
			FileWriter pubfw = new FileWriter(filePath + "/publicKey.key");
			FileWriter prifw = new FileWriter(filePath + "/privateKey.key");
			BufferedWriter pubbw = new BufferedWriter(pubfw);
			BufferedWriter pribw = new BufferedWriter(prifw);
			pubbw.write(publicKeyString);
			pribw.write(privateKeyString);
			pubbw.flush();
			pubbw.close();
			pubfw.close();
			pribw.flush();
			pribw.close();
			prifw.close();
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
}

    /**
     * 去除密钥的多余信息
     *
     * @param key 公钥或私钥字符串
     * @return Base64的密钥 base 64 key
     */
    public static String getBase64Key(String key) {
		key = key.replaceAll("-----BEGIN (.*)-----", "");
		key = key.replaceAll("-----END (.*)----", "");
		key = key.replaceAll("\r\n", "");
		key = key.replaceAll("\n", "");
		return key;
	}
    /**
     * 从文件中加载密钥
     *
     * @param fileName 公钥或私钥的文件名
     * @return 字符串形式的密钥 ，去除-----BEGIN (.*)-----等多余信息
     */
    public static String loadKeyFromFile(String fileName) {
		byte[] keyBytes = loadRawKeyFromFile(fileName);

		// convert to der format
		return getBase64Key(new String(keyBytes));
	}

    /**
     * 从文件中加载密钥
     *
     * @param fileName 公钥或私钥的文件名
     * @return 字符串形式的密钥 byte [ ]
     */
    public static byte[] loadRawKeyFromFile(String fileName) {
		InputStream resourceAsStream = RSAUtil.class.getClassLoader().getResourceAsStream(fileName);
		DataInputStream dis = new DataInputStream(resourceAsStream);
		byte[] keyBytes = null;
		try {
			keyBytes = new byte[resourceAsStream.available()];
			dis.readFully(keyBytes);
			dis.close();
		} catch (IOException e) {
			throw new SystemException("Failed to load public key from file '" + fileName + "'", e);
		}
		return keyBytes;
	}

    /**
     * Load private key by str rsa private key.
     * 加载秘钥
     * @param privateKeyStr the private key str
     * @return the rsa private key
     */
    public static RSAPrivateKey loadPrivateKeyByStr(String privateKeyStr) {
		try {
			byte[] buffer = Base64.getDecoder().decode(privateKeyStr);
			PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(buffer);
			KeyFactory keyFactory = KeyFactory.getInstance("RSA", "BC"); // KeyFactory.getInstance("RSA");
			return (RSAPrivateKey) keyFactory.generatePrivate(keySpec);
		} catch (NoSuchAlgorithmException e) {
			throw new SystemException("无此算法", e);
		} catch (InvalidKeySpecException e) {
			throw new SystemException("私钥非法", e);
		} catch (NullPointerException e) {
			throw new SystemException("私钥数据为空", e);
		} catch (NoSuchProviderException e) {
			throw new SystemException("no such provider: RSA, BC", e);
		}
	}

 /**
     * 公钥加密过程
     *
     * @param publicKey     公钥
     * @param plainTextData 明文数据
     * @return 密文 byte [ ]
     */
    public static byte[] encrypt(RSAPublicKey publicKey, byte[] plainTextData) {
		if (publicKey == null) {
			throw new SystemException("加密公钥为空");
		}
		Cipher cipher = null;
		try {
			// 使用默认RSA
			cipher = Cipher.getInstance("RSA");
			// cipher= Cipher.getInstance("RSA", new BouncyCastleProvider());
			cipher.init(Cipher.ENCRYPT_MODE, publicKey);
			byte[] output = cipher.doFinal(plainTextData);
			return output;
		} catch (NoSuchAlgorithmException e) {
			throw new SystemException("无此加密算法", e);
		} catch (NoSuchPaddingException e) {
			throw new SystemException("无此加密算法", e);
		} catch (InvalidKeyException e) {
			throw new SystemException("加密公钥非法,请检查", e);
		} catch (IllegalBlockSizeException e) {
			throw new SystemException("明文长度非法", e);
		} catch (BadPaddingException e) {
			throw new SystemException("明文数据已损坏", e);
		}
	}

    /**
     * 私钥加密过程
     *
     * @param privateKey    私钥
     * @param plainTextData 明文数据
     * @return 密文 byte [ ]
     * @throws Exception 加密过程中的异常信息
     */
    public static byte[] encrypt(RSAPrivateKey privateKey, byte[] plainTextData) throws Exception {
		if (privateKey == null) {
			throw new SystemException("加密私钥为空");
		}
		Cipher cipher = null;
		try {
			// 使用默认RSA
			cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding", "BC");// Cipher.getInstance("RSA");
			cipher.init(Cipher.ENCRYPT_MODE, privateKey);
			byte[] output = cipher.doFinal(plainTextData);
			return output;
		} catch (NoSuchAlgorithmException e) {
			throw new SystemException("无此加密算法", e);
		} catch (NoSuchPaddingException e) {
			throw new SystemException("系统中无此填充机制", e);
		} catch (InvalidKeyException e) {
			throw new SystemException("加密私钥非法,请检查", e);
		} catch (IllegalBlockSizeException e) {
			throw new SystemException("明文长度非法", e);
		} catch (BadPaddingException e) {
			throw new SystemException("明文数据已损坏", e);
		}
	}

    /**
     * 私钥解密过程
     *
     * @param privateKey 私钥
     * @param cipherData 密文数据
     * @return 明文 byte [ ]
     */
    public static byte[] decrypt(RSAPrivateKey privateKey, byte[] cipherData) {
		if (privateKey == null) {
			throw new SystemException("解密私钥为空");
		}
		Cipher cipher = null;
		try {
			// 使用默认RSA
			cipher = Cipher.getInstance("RSA");
			// cipher= Cipher.getInstance("RSA", new BouncyCastleProvider());
			cipher.init(Cipher.DECRYPT_MODE, privateKey);
			byte[] output = cipher.doFinal(cipherData);
			return output;
		} catch (NoSuchAlgorithmException e) {
			throw new SystemException("无此解密算法", e);
		} catch (NoSuchPaddingException e) {
			throw new SystemException("系统中无此填充机制", e);
		} catch (InvalidKeyException e) {
			throw new SystemException("解密私钥非法", e);
		} catch (IllegalBlockSizeException e) {
			throw new SystemException("密文长度非法");
		} catch (BadPaddingException e) {
			throw new SystemException("密文数据已损坏", e);
		}
	}

    /**
     * 公钥解密过程
     *
     * @param publicKey  公钥
     * @param cipherData 密文数据
     * @return 明文 byte [ ]
     * @throws Exception 解密过程中的异常信息
     */
    public static byte[] decrypt(RSAPublicKey publicKey, byte[] cipherData) throws Exception {
		if (publicKey == null) {
			throw new SystemException("解密公钥为空");
		}
		Cipher cipher = null;
		try {
			// 使用默认RSA
			cipher = Cipher.getInstance("RSA");
			// cipher= Cipher.getInstance("RSA", new BouncyCastleProvider());
			cipher.init(Cipher.DECRYPT_MODE, publicKey);
			byte[] output = cipher.doFinal(cipherData);
			return output;
		} catch (NoSuchAlgorithmException e) {
			throw new SystemException("无此解密算法", e);
		} catch (NoSuchPaddingException e) {
			throw new SystemException("系统中无此填充机制", e);
		} catch (InvalidKeyException e) {
			throw new SystemException("解密公钥非法", e);
		} catch (IllegalBlockSizeException e) {
			throw new SystemException("密文长度非法");
		} catch (BadPaddingException e) {
			throw new SystemException("密文数据已损坏");
		}
	}

前端加密

const JSEncrypt = window.JSEncrypt;

export function rsa(str) {
  const jse = new JSEncrypt();
  const { publicKey } = xxx;//从后端接口获取publicKey
  jse.setPublicKey(publicKey);
  return jse.encrypt(str)
}


export default function(str) {
  return rsa(str)
}

export const decrypt = async str => {
  return new Promise((resolve, reject) => {
    后端解密接口(str)
      .then(res => {
        if (res.data.code === "success") {
          resolve(res.data.data);
        } else {
          reject(res);
        }
      })
      .catch(err => {
        reject(err)
      });
  })
}

后端解密接口

//eg: 后端获取publicKey接口
@GetMapping("getRsaPublicKey")
public ResultResp getRsaPublicKey() {
    String key = RSAUtil.loadKeyFromFile("rsaPublicKey.key");
    return success(key);
}

//eg:后端解密接口
@GetMapping("getDecryptRsaPwd")
public Result