解决cryptoJS.AES默认参数加密,java无法解密的问题

有时候我们需要跨编程语言进行加密加密。比如nodejs里面加密，java里面解密，或者反过来java加密，nodejs解密。node可以使用cryptojs，java可以使用javax.crypto.Cipher包。

网上有很多关于这方面的文章。然而如果node使用了默认的参数进行加密（比如现有业务已经生成了一些已经加密的数据），需要java进行解密，这时候按照默认的方法就无法正常解密了。一般的aes加密使用的是16位的key，而cryptojs默认的key可以任意长度。

cryptoJS.AES默认参数加密代码：

const cryptoJS = require("crypto-js");
const encryptedValue = cryptoJS.AES.encrypt(value, secret).toString()

对应的java解密的示例代码：

  try {
            byte[] cipherData = cn.hutool.core.codec.Base64.decode(encryptedText);

            byte[] saltData = Arrays.copyOfRange(cipherData, 8, 16);

            MessageDigest md5 = MessageDigest.getInstance("MD5");

            final byte[][] keyAndIV = GenerateKeyAndIV(32, 16, 1, saltData, secret.getBytes(StandardCharsets.UTF_8), md5);

            SecretKeySpec key = new SecretKeySpec(keyAndIV[0], "AES");

            IvParameterSpec iv = new IvParameterSpec(keyAndIV[1]);

            byte[] encrypted = Arrays.copyOfRange(cipherData, 16, cipherData.length);

            Cipher aesCBC = Cipher.getInstance("AES/CBC/PKCS5Padding");

            aesCBC.init(Cipher.DECRYPT_MODE, key, iv);

            byte[] decryptedData = aesCBC.doFinal(encrypted);
            return new String(decryptedData, StandardCharsets.UTF_8);
        } catch (Exception e) {
            //log.error("aesDecrypt error.param={}", encryptedText, e);
            return null;
        }

以上代码来自参考自：https://www.pianshen.com/question/31931314701/

上面只是演示了如何进行node加密，java解密；而java默认加密的值，node也是无法解密的，需要采用以下写法。

java加密示例代码

        try {
            byte[] input = datastr.getBytes();
            // 以下两个变量不可修改，否则java加密的，node无法解密
            byte[] saltData = "DFބf$t:".getBytes();
            byte[] preData = "Salted__".getBytes();
            MessageDigest md5 = MessageDigest.getInstance("MD5");
            final byte[][] keyAndIV = GenerateKeyAndIV(32, 16, 1, saltData, secret.getBytes(StandardCharsets.UTF_8), md5);

            SecretKeySpec key = new SecretKeySpec(keyAndIV[0], "AES");

            IvParameterSpec iv = new IvParameterSpec(keyAndIV[1]);
            Cipher aesCBC = Cipher.getInstance("AES/CBC/PKCS5Padding");

            aesCBC.init(Cipher.ENCRYPT_MODE, key, iv);

            byte[] encrypt = aesCBC.doFinal(input);
            byte[] encryptedData = addBytes(saltData, encrypt);
            return cn.hutool.core.codec.Base64.encode(addBytes(preData, encryptedData));
        } catch (Exception e) {
            log.error("aesEncrypt error.param={}", datastr, e);
            return null;
        }

上述代码亲测有效，使用前可以自己测试测试

对应的node解密示例代码

const cryptoJS = require("crypto-js");
let decryptedValue = cryptoJS.AES.decrypt(value, secret).toString(cryptoJS.enc.Utf8);

完整代码示例

import lombok.extern.slf4j.Slf4j;

import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import java.nio.charset.StandardCharsets;
import java.security.DigestException;
import java.security.MessageDigest;
import java.util.Arrays;

/**
 *
 * 兼容node
 *
 */
@Slf4j
public class AESUtils {

    public static String aesEncrypt(String datastr, String secret) {
        try {
            byte[] input = datastr.getBytes();
            // 以下两个变量不可修改，否则java加密的，node无法解密
            byte[] saltData = "DFބf$t:".getBytes();
            byte[] preData = "Salted__".getBytes();
            MessageDigest md5 = MessageDigest.getInstance("MD5");
            final byte[][] keyAndIV = GenerateKeyAndIV(32, 16, 1, saltData, secret.getBytes(StandardCharsets.UTF_8), md5);

            SecretKeySpec key = new SecretKeySpec(keyAndIV[0], "AES");

            IvParameterSpec iv = new IvParameterSpec(keyAndIV[1]);
            Cipher aesCBC = Cipher.getInstance("AES/CBC/PKCS5Padding");

            aesCBC.init(Cipher.ENCRYPT_MODE, key, iv);

            byte[] encrypt = aesCBC.doFinal(input);
            byte[] encryptedData = addBytes(saltData, encrypt);
            return cn.hutool.core.codec.Base64.encode(addBytes(preData, encryptedData));
        } catch (Exception e) {
            log.error("aesEncrypt error.param={}", datastr, e);
            return null;
        }
    }

    public static String aesDecrypt(String encryptedText, String secret){
        // 参考文章：https://www.pianshen.com/question/31931314701/
        try {
            byte[] cipherData = cn.hutool.core.codec.Base64.decode(encryptedText);

            byte[] saltData = Arrays.copyOfRange(cipherData, 8, 16);

            MessageDigest md5 = MessageDigest.getInstance("MD5");

            final byte[][] keyAndIV = GenerateKeyAndIV(32, 16, 1, saltData, secret.getBytes(StandardCharsets.UTF_8), md5);

            SecretKeySpec key = new SecretKeySpec(keyAndIV[0], "AES");

            IvParameterSpec iv = new IvParameterSpec(keyAndIV[1]);

            byte[] encrypted = Arrays.copyOfRange(cipherData, 16, cipherData.length);

            Cipher aesCBC = Cipher.getInstance("AES/CBC/PKCS5Padding");

            aesCBC.init(Cipher.DECRYPT_MODE, key, iv);

            byte[] decryptedData = aesCBC.doFinal(encrypted);
            return new String(decryptedData, StandardCharsets.UTF_8);
        } catch (Exception e) {
            log.error("aesDecrypt error.param={}", encryptedText, e);
            return null;
        }
    }

    public static byte[][] GenerateKeyAndIV(int keyLength, int ivLength, int iterations, byte[] salt, byte[] password, MessageDigest md) {

        int digestLength = md.getDigestLength();

        int requiredLength = (keyLength + ivLength + digestLength - 1) / digestLength * digestLength;

        byte[] generatedData = new byte[requiredLength];

        int generatedLength = 0;

        try {

            md.reset();

// Repeat process until sufficient data has been generated

            while (generatedLength < keyLength + ivLength) {

// Digest data (last digest if available, password data, salt if available)

                if (generatedLength > 0)

                    md.update(generatedData, generatedLength - digestLength, digestLength);

                md.update(password);

                if (salt != null)

                    md.update(salt, 0, 8);

                md.digest(generatedData, generatedLength, digestLength);

// additional rounds

                for (int i = 1; i < iterations; i++) {

                    md.update(generatedData, generatedLength, digestLength);

                    md.digest(generatedData, generatedLength, digestLength);

                }

                generatedLength += digestLength;

            }

// Copy key and IV into separate byte arrays

            byte[][] result = new byte[2][];

            result[0] = Arrays.copyOfRange(generatedData, 0, keyLength);

            if (ivLength > 0)

                result[1] = Arrays.copyOfRange(generatedData, keyLength, keyLength + ivLength);

            return result;

        } catch (DigestException e) {

            throw new RuntimeException(e);

        } finally {

// Clean out temporary data

            Arrays.fill(generatedData, (byte)0);

        }

    }

    public static byte[] addBytes(byte[] data1, byte[] data2) {

        byte[] data3 = new byte[data1.length + data2.length];

        System.arraycopy(data1, 0, data3, 0, data1.length);

        System.arraycopy(data2, 0, data3, data1.length, data2.length);

        return data3;

    }

    public static void main(String[] args) {
        String secret = "aabbccddeeff";
        String datastr = "{\"m\":\"images\",\"u\":\"0\",\"t\":\"20230322\",\"f\":\"16794597950146230.png\"}";

        String t = aesEncrypt(datastr, secret);
        System.out.println(t);
        System.out.println(aesDecrypt(t, secret));

    }
}