突然看到一个APP叫乐尚视界，能看十几个网站的vip视频，感觉和之前的网页在线观看vip视频没有实名区别。
在抓包的时候发现了APP对数据包进行了加密，对APP进行反编译后，一边练手一边写出下面的加解密脚本，仅供参考。

/*
 * Copyright sky 2018-01-18 Email:sky@03sec.com.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.javaweb.demo;

import javax.crypto.*;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import java.io.UnsupportedEncodingException;
import java.math.BigInteger;
import java.nio.ByteBuffer;
import java.security.*;
import java.util.Base64;

public class LeeShang {


    public static String aaaaa(String var0) {
        byte[] var3;
        try {
            var3 = MessageDigest.getInstance("md5").digest(var0.getBytes());
        } catch (NoSuchAlgorithmException var2) {
            throw new RuntimeException("没有md5这个算法！");
        }

        var0 = (new BigInteger(1, var3)).toString(16);

        for (int var1 = 0; var1 < 32 - var0.length(); ++var1) {
            var0 = "0" + var0;
        }

        return var0;
    }

    public static byte[] encrypt(byte[] paramArrayOfByte, String password, String secureRandom) {
        try {
            SecretKeySpec keySpec     = secretKeySpec(password);
            Cipher        localCipher = Cipher.getInstance("AES/CBC/NoPadding");
            while (paramArrayOfByte.length % 16 != 0) { //如果paramArrayOfByte的长度不是16的倍数AES加密会报错，这边对paramArrayOfByte进行长度扩展，使它必须为16的倍数
                byte[] tmpByte = {0x00};
                paramArrayOfByte = ByteBuffer.allocate(paramArrayOfByte.length + 1).put(tmpByte).array();
            }
            localCipher.init(2, keySpec, ivParameterSpec(secureRandom));
            paramArrayOfByte = localCipher.doFinal(paramArrayOfByte);
            return paramArrayOfByte;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    public static byte[] decrypt(byte[] content, String password, String secureRandom) {
        try {
            SecretKeySpec keySpec = secretKeySpec(password);
            Cipher        cipher  = Cipher.getInstance("AES/CBC/NoPadding");// 创建密码器
            cipher.init(Cipher.DECRYPT_MODE, keySpec, ivParameterSpec(secureRandom));// 初始化
            byte[] result = cipher.doFinal(content);
            return result; // 加密
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    private static SecretKeySpec secretKeySpec(String var0) {
        Object var2 = null;
        String var1 = var0;
        if (var0 == null) {
            var1 = "";
        }

        StringBuffer var4 = new StringBuffer(16);
        var4.append(var1);

        while (var4.length() < 16) {
            var4.append("0");
        }

        if (var4.length() > 16) {
            var4.setLength(16);
        }

        byte[] var5;
        try {
            var5 = var4.toString().getBytes("UTF-8");
        } catch (UnsupportedEncodingException var3) {
            var3.printStackTrace();
            var5 = (byte[]) var2;
        }

        return new SecretKeySpec(var5, "AES");
    }


    private static IvParameterSpec ivParameterSpec(String var0) {
        Object var2 = null;
        String var1 = var0;
        if (var0 == null) {
            var1 = "";
        }

        StringBuffer var4 = new StringBuffer(16);
        var4.append(var1);

        while (var4.length() < 16) {
            var4.append("0");
        }

        if (var4.length() > 16) {
            var4.setLength(16);
        }

        byte[] var5;
        try {
            var5 = var4.toString().getBytes("UTF-8");
        } catch (UnsupportedEncodingException var3) {
            var3.printStackTrace();
            var5 = (byte[]) var2;
        }

        return new IvParameterSpec(var5);
    }

    public static String convertByteArrayToString(byte[] var1) {

        String value = new String(var1);
        return value;
    }

    public static void main(String[] args) {
        String key          = "$75k!xxH&$EhQLmv";
        String secureRandom = aaaaa("$75k!xxH&$EhQLmv").substring(0, 16);
        //解密
        String content      = "jStVIqaSUdIm0aF8mcs8GAjohYApwOUYVXenyG7zeQV86ZFrmO3Z1ixPLEM9srKRaVR1nE+0V3gTKGtlgwWgCg==";
        System.out.println(convertByteArrayToString(decrypt(Base64.getDecoder().decode(content), key, secureRandom)));
        //加密
        String s = "{'token':'x','code':'ghhhh'}";
        System.out.println(Base64.getEncoder().encodeToString(encrypt(s.getBytes(), key, secureRandom)));
    }
}