Decrypt data using _Crypt_DecryptData

[AoRaToS]

Hello,

I am changing the way some strings are encrypted and decrypted from the old StringEncrypt to the new one.

One thing I noticed is that when you try and decrypt something that is simply blank a weird result is returned as seen in the screenshot below.

In case you want to know why this would ever happen, I have my app auto-fill an Inputbox with the decrypted variable but the decrypted variable might be blank so this is used instead.

I know how to code around it, just wondering if this result is expected, cause MSDN says something about the subject but I'm not sure this is the result it mentions.

Code used:

#include <Crypt.au3>


MsgBox(0,"",StringEncrypt(False, "", ""))


Func StringEncrypt($fEncrypt, $sData, $sPassword)
    _Crypt_Startup() ; Start the Crypt library.
    Local $sReturn = ''
    If $fEncrypt Then ; If the flag is set to True then encrypt, otherwise decrypt.
        $sReturn = _Crypt_EncryptData($sData, $sPassword, $CALG_AES_128)
    Else
        $sReturn = BinaryToString(_Crypt_DecryptData($sData, $sPassword, $CALG_AES_128))
    EndIf
    _Crypt_Shutdown() ; Shutdown the Crypt library.
    Return $sReturn
EndFunc   ;==>StringEncrypt

Edited January 21, 2014 by AoRaToS

[BrewManNH]

I've gotten that string many times trying to decrypt something that isn't encrypted.

[AoRaToS]

Shouldn't it return an empty string?

[Melba23]

AoRaToS,

I knew I had seen something like this before. This thread shows a similar thing - but it took some finding!

I can only suggest you code around it - the functions used in the Crypt library are direct calls to the Windows DLL and so I do not believe that there is anything AutoIt can do to prevent this from happening with empty strings.

M23

[BrewManNH]

The function is returning a -1 when it encounters a problem and returns an error of 20, so when you run BinaryToString(-1) you get that result. Check for errors before trying to continue and the problem goes away.