Reproduction of XOR and encryption decryption

  In many music players , A lot of music needs to be downloaded VIP Or pay to play , For example, a cloud , So-and-so , Music, etc . They all use XOR and encryption methods to encrypt files . This blog is for Network Security Learning CSDN A great god “ Ghost hand 56“” Blog recurrence , This is a simple decryption process , But it is still recommended that readers who read this blog download genuine songs , Protect copyright and green network environment together . 

Reference to the original ：https://blog.csdn.net/qq_38474570/article/details/87878235

First of all, we can freely download a song of ourselves in a cloud bian Favorite songs , And a prompt pops up that we need members to continue downloading

At this point, we can find our own cache directory in the settings of Netease cloud music

It should be noted that the cached file directory is a hidden directory , You need to check the hidden items .

Sort by modification date Find the one that meets the modification time Suffix named .uc The largest file of Namely encryption Later documents The other one should be the lyrics file ( Before that, it's best to empty the cache directory ), The way to empty the cache is as follows

Now let's go back to the folder just now , You can find the music file we are trying to download in the folder .

We turn on 010Editor, Select open file in the file in the upper left corner , Select the cache file we just found .

After opening, you can find the following 16 Hexadecimal data , We can find a very obvious feature —— The most data is A3 So it can be inferred that A3 Is the meaningless character after encryption 0 Generally speaking, the encryption method of audio is not too complicated And the simplest XOR encryption XOR encryption is reversible , Here we select the tool in the toolbar above to try to decrypt .

So just select all the data Click on the menu -> Tools -> Hexadecimal operation -> Binary XOR Modify the processing data to be unsigned Hexadecimal Then on A3 To engage in exclusive or

We try to use XOR to remove the meaningless characters after encryption A3

Modify in the pop-up operation box as shown in the following figure . Click OK to try decryption .

  After clicking OK , We can find many meaningless characters in our data 0, Here's the picture , At the same time, the file also becomes meaningful. Click Save to close our 010editor.

  Modify the suffix of the decrypted file to .MP3, We try to play , It can be found that the music can be played normally .

Last , XOR has been encrypting music for many years , I hope these development companies can optimize the encryption algorithm , Solve this loophole . After reading this blog, readers also hope that you can download genuine songs , Maintain the network environment , Don't make illegal profits in this way ！