Encrypting values

[erebus]

Hello all,

I have written two scripts where the first writes some game CD keys to an ini file as values and the second one reads them. The problem is that while the .ini file is located in an SMB Windows share folder, can be manually read by everyone in the LAN since the CD key values are human readable.

Can someone throw me a bone of how to achieve a (basic) encryption/decryption for these values to avoid this issue?

Hint1: CD key format example:

a. HJ7MVH-EKZ9-BVM6Z6-FYDX-CMGTBG (Warcraft III)

b. RV9VEM-7T67-6H7C8E-K7WD-JBHCE2 (Frozen Throne)

Hint2: The idea is to use the encryption, not the hidden windows' shares.

Thanks in advance for your time..

[ezzetabi]

What about a Rot-13? It is easy to implement, but weak.

It is enough for you? Otherwiseuse the idea.com scripts.

[CyberSlug]

You could instead/additionaly re-order the sections of the key:

; PLAIN TEXT

$cdkey = "EXMPL-CDKEY-GOES0-HERE0-12345"

$key = StringSplit($cdkey, "-")

; ENCRYPTING

$encrypted = $key[2] & $key[5] & $key[1] & $key[4] & $key[3]

; this stores CDKEY-12345-EXMPL-HERE0-GOES0

;.....

; DECRYPTING

$d = StringSplit($encrypted, "-")

$decrypted = $d[3] & $d[1] & $d[5] & $d[4] & $d[2]

[ezzetabi]

Sweet.

[erebus]

@CyberSlug: This is a good idea, however someone can easily image the trick if manages to see the ini file. I 've also thought of reversing some of the splitted strings, but it makes no difference; it's too weak.

@ezzetabi: Thanks for the tip, I was totally unaware of the ROT13 method. However as I checked a bit, it's a game for someone to break it (check the online tool @ http://www.rot13.com for instance).

Searching the AutoIT forums I found your two great ROT13 functions in an old post. If we take the CyberSlug's function as an example (which code seems more compact) could we alter it in an easy way to customize the ROT13 encryption?

Correct me if I am wrong but I think that this kind of encryption is based on numbers. By using total different numbers in the function (or even better a passphrase) don't we achieve a new encryption method (assuming that the new encryption source code is unavailable)?

Thank you.

Edited November 11, 2004 by erebus

[Mr.Wizard]

Try this:

Opt("MustDeclareVars", 1)

dim $notencrypted = "HJ7MVH-EKZ9-BVM6Z6-FYDX-CMGTBG (Warcraft III)"
dim $encrypted = encdec($notencrypted)
dim $decrypted = encdec($encrypted)

MsgBox(0, "xor encryption test", "before encryption: " & $notencrypted & @crlf & @crlf & "after encryption: " & $encrypted & @crlf & @crlf & "after decryption: " & $decrypted) 

Func EncDec($original)
    dim $modified
    dim $key = "I am the magic key"
    dim $pos_original, $pos_key
    
    For $pos_original = 1 To StringLen($original)
        If $pos_key = StringLen($key) Then
            $pos_key = 1
        Else
            $pos_key = $pos_key + 1
        EndIf

        $modified = $modified & Chr(BitXOR(Asc(StringMid($original, $pos_original, 1)), Asc(StringMid($key, $pos_key, 1)), 255))
    Next
        
    Return $modified
EndFunc

[ezzetabi]

Check here.

http://www.autoitscript.com/forum/index.php?showtopic=2611

Using idea.com and this sample code you should not have problems. Do the following.

Encrypt the file,

Make a script the decrypt, read the .ini encrypt again.

Enjoy.

[erebus]

@ezzetabi: I really like the way you code pal. This is another excellent idea, thank you very much!

@Mr.Wizard: Great functions too, thanks a lot for your time. Amazing results!

[JSThePatriot]

Hey... I just created a program that will use AxCrypt (look on sourceforge for it) that will automatically encrypt files. I think AxCrypt would be what you are looking for as you can have AutoIt automate it. It has command line parameters.

Once I get home I will give you the web address and such if you are interested. I will be posting my script in the scripts and scraps section once it is finished.

JS

[erebus]

Thank you very much, I 've already used Mr.Wizard's solution so as to use something quick and handy. I would like to see your adaptation with AxCrypt, it should be very interesting!