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I want to decrypt a string (HWID) which is being sent to my filter as weird characters.

It was working fine until someone released the bypass for it. So basically I want to decrypt it and check if it's real or fake.

How I'm getting the string (HWID)?

this.hwid = current.ReadAscii(); //reading the packet

I wanna decrypt it (XOR), this is how the string (HWID) looks like; "y'2&dxw|rrbrne{"df!4* |/qd|'`-r5s "

Ignore the quotes

Any help would be appreciated;

How did I get this idea? A friend of mine who actually made the DLL which sends the string (HWID) gave me a hint. But I don't even know what's XOR. And Please if you don't understand what I mean just comment what u don't understand.

Skipper
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    "xor" is not an encryption method, although it can be used in encryption. You need to know how this string was encrypted, and what the key is. Ask your friend. – Blorgbeard Jul 08 '15 at 04:17
  • So I have to get the key? Its a must? – Skipper Jul 08 '15 at 04:18
  • XOR can be used as encryption method, but it's not recomended. There are a lot of better algorithms, wherever I see the hwid is a sum of the installed hardware in the computer, I don't think this was encrypted. You are reading it as a string, try read it as hex. – Exos Jul 08 '15 at 04:23
  • Well, that's the point of encryption. You need the key. If it's weak encryption (which is likely if your friend just made it up) you may be able to crack it without the key. – Blorgbeard Jul 08 '15 at 04:23
  • How could I crack it without a key? – Skipper Jul 08 '15 at 04:27
  • Do you know what a decrypted HWID would look like? Are there any strings you know it might contain? In other words, if you guessed the key correctly, could you tell? – Blorgbeard Jul 08 '15 at 04:30
  • That's probably a No. nevermind then thanks :D – Skipper Jul 08 '15 at 04:31
  • Then how were you going to check if it was real or fake? Anyway, if you're interested in learning about this stuff, I recommend working through http://cryptopals.com/sets/1/ – Blorgbeard Jul 08 '15 at 04:32

1 Answers1

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x-or is a boolean mathematical operation. You can learn all about it over here https://en.wikipedia.org/wiki/Exclusive_or

To decrypt using x-or in C# you need to use the XOR operator like this c = a ^ b;

To decrypt your string you need the key (something to x-or it with) and then perform the x-or one character at a time. This will be something like converting the strong to a bytearray and then processing one character at a time.

That would be like this question XOR function for two Hex byte arrays

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