[Fixed] _Crypt_DeriveKey Not working as Intended

[EmilyLove]

Big thanks to CrypticKiwi for helping me with this issue. Click HERE to go to his solution.

 

It was working earlier today but now all of a sudden it doesn't work. I literally have no idea why it won't work. It should look like 0x30783030453638434130 but it will only generate keys that looks like 0x016A0C08 now. (Hint: It's noticibly shorter)

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#RequireAdmin
#include "crypt.au3"
#include "Date.au3"
#include <ButtonConstants.au3>
#include <GUIConstantsEx.au3>
#include <StaticConstants.au3>
#include <WindowsConstants.au3>
#include <MsgBoxConstants.au3>
#Region ### START Koda GUI section ### Form=
$Form1 = GUICreate("Form1", 154, 121, 192, 124)
$Label1 = GUICtrlCreateLabel("What would you like to do?", 8, 8, 141, 17)
$Button1 = GUICtrlCreateButton("Encrypt", 8, 40, 137, 25)
$Button2 = GUICtrlCreateButton("Decrypt", 8, 80, 137, 25)
#EndRegion ### END Koda GUI section ###
Global $key_encrypted = _Crypt_DeriveKey("1WSUJpOq1ca2H9DMRhs14iy3fI04IBFp", $CALG_RC4);Does not generate a working key. What's going on?
Global $date, $input, $data, $result, $key
GUISetState(@SW_SHOW)

While 1
    $nMsg = GUIGetMsg()
    Switch $nMsg
        Case $GUI_EVENT_CLOSE
            Exit
        Case $Button1;I assume works as Intended.

            GUISetState(@SW_HIDE)
            $date = ""
            $date = _DateDiff("s", "1970/01/01 00:00:00", _NowCalc())

            $data = ""
            $data = _Crypt_EncryptData($date, $key_encrypted, $CALG_RC4)

            $input = ""
            $input = InputBox("Crypter", "Enter the data to be encrypted.", $data)

            $result = ""
            $result = _Crypt_EncryptData($input, $key_encrypted, $CALG_RC4)

            
            InputBox("Crypter", "Your Data Encrypted is", $result)
            InputBox("Crypter", "Your Key Encrypted is", $key_encrypted)

            GUISetState(@SW_SHOW)
        Case $Button2;Works as Intended, as it decrypts previously successful encrypted variables just fine.
            GUISetState(@SW_HIDE)

            $input = ""
            $input = InputBox("Crypter", "Enter the data to be decrypted.")
            

            $key = ""
            $key = InputBox("Crypter", "Enter the key to decrypt the data.")
            

            $result = ""
            $result = BinaryToString(_Crypt_DecryptData($input, $key, $CALG_RC4))
            

            InputBox("Crypter", "Your Data Decrypted is", $result)

            GUISetState(@SW_SHOW)
    EndSwitch
WEnd

 

Edited August 24, 2015 by BetaLeaf
Fixed, Thanks CrypticKiwi

[Melba23]

BetaLeaf,

The return you get from the _Crypt_DeriveKey function is a pointer to the generated key (check with VarGetType) - and as such I would expect it to look like "0x016A0C08" as that the normal format for that datatype. Why do you think it should be so much longer?

M23

[EmilyLove]

BetaLeaf,

The return you get from the _Crypt_DeriveKey function is a pointer to the generated key (check with VarGetType) - and as such I would expect it to look like "0x016A0C08" as that the normal format for that datatype. Why do you think it should be so much longer?

M23

When I ran _Crypt_DeriveKey earlier that day, it gave me a much longer code that worked. This shorter code fails to properly decrypt the data I give it using _Crypt_DecryptData. Just to be clear, this script is just suppose to generate a key on boot and encrypt some data, with a function to check and make sure it can decrypt fine.  Im using Windows 10 btw.

For example I encrypted the word "test". It gave me the EncryptedData 0xBB34681A
and the key 0x026FBD20. Trying to decrypt it turns "test" into "[¿TÁ"

Now you mentioned it is unexpected that the key is longer. Idk why you say that. This encrypted data contains my email, and it decrypts fine. 

Encrypted Data 0x5127F1C0426C24FCDE778CA6FA5B586F7F73

Key 0x30783030453638434130

Edited August 24, 2015 by BetaLeaf
example.

[Melba23]

BetaLeaf,

The function works fine for me:

#include <Crypt.au3>
#include <MsgBoxConstants.au3>

Example()

Func Example()
    Local $aStringsToEncrypt[5] = ["AutoIt", "SciTE", "Crypt", ".au3", "42"]
    Local $aEncryptedStrings[5], $aDecryptedStrings[5]

    Local $sEnCrypted = "", $sDeCrypted = ""

    Local $hKey = _Crypt_DeriveKey("CryptPassword", $CALG_RC4) ; Declare a password string and algorithm to create a cryptographic key.
MsgBox($MB_SYSTEMMODAL, "Key Pointer", $hKey & @CRLF & @CRLF & VarGetType($hKey))


    For $i = 0 To UBound($aStringsToEncrypt) - 1
        $aEncryptedStrings[$i] = _Crypt_EncryptData($aStringsToEncrypt[$i], $hKey, $CALG_USERKEY)
        $sEnCrypted &= $aStringsToEncrypt[$i] & @TAB & " = " & $aEncryptedStrings[$i] & @CRLF ; Encrypt the text with the cryptographic key.
        $aDecryptedStrings[$i] = _Crypt_DecryptData($aEncryptedStrings[$i], $hKey, $CALG_USERKEY)
        $sDeCrypted &= $aEncryptedStrings[$i] & @TAB & " = " & BinaryToString($aDecryptedStrings[$i]) & @CRLF ; Encrypt the text with the cryptographic key.
    Next

    MsgBox($MB_SYSTEMMODAL, "Encrypted data", $sEnCrypted & @CRLF & @CRLF & $sDeCrypted)

    _Crypt_DestroyKey($hKey) ; Destroy the cryptographic key.
EndFunc   ;==>Example

Now you mentioned it is unexpected that the key is longer. Idk why you say that

I say that because the returned value is a pointer and I would expect a pointer (on my 32 bit machine) to have the format 0x########. Were you perhaps running the script on a 64-bit machine when you got the longer return value?

M23

[EmilyLove]

I tried running in both 32 bit and 64 bit. The longer pointer seems to come from the 64 bit exe. I never build 64 bit exe so I have no idea why it did this. Also, I still cannot decrypt my test data with the code I posted in the OP

[Melba23]

BetaLeaf,

The longer pointer seems to come from the 64 bit exe

Exactly - pointers are sized according to the "bitness" of OS on which they run. So that is one mystery solved.

As to the failure to decrypt, please post the code (see here how to do it) that you are using to en/decrypt and we can see what might be the problem.

M23

[EmilyLove]

I already posted the problem script in the Original Post(OP).

[CrypticKiwi]

Got it, it has to be  Number($Key) while recieving decryption input from inputbox

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#RequireAdmin
#include "crypt.au3"
#include "Date.au3"
#include <ButtonConstants.au3>
#include <GUIConstantsEx.au3>
#include <StaticConstants.au3>
#include <WindowsConstants.au3>
#include <MsgBoxConstants.au3>
#Region ### START Koda GUI section ### Form=
$Form1 = GUICreate("Form1", 154, 121, 192, 124)
$Label1 = GUICtrlCreateLabel("What would you like to do?", 8, 8, 141, 17)
$Button1 = GUICtrlCreateButton("Encrypt", 8, 40, 137, 25)
$Button2 = GUICtrlCreateButton("Decrypt", 8, 80, 137, 25)
#EndRegion ### END Koda GUI section ###
Global $key_encrypted = _Crypt_DeriveKey("1WSUJpOq1ca2H9DMRhs14iy3fI04IBFp", $CALG_RC4);Does not generate a working key. What's going on?
Global $date, $input, $data, $result, $key
GUISetState(@SW_SHOW)

While 1
    $nMsg = GUIGetMsg()
    Switch $nMsg
        Case $GUI_EVENT_CLOSE
            Exit
        Case $Button1;I assume works as Intended.

            GUISetState(@SW_HIDE)
            $date = ""
            $date = _DateDiff("s", "1970/01/01 00:00:00", _NowCalc())

            $data = ""
            $data = _Crypt_EncryptData($date, $key_encrypted, $CALG_RC4)

            $input = ""
            $input = InputBox("Crypter", "Enter the data to be encrypted.", $data)

            $result = ""
            $result = _Crypt_EncryptData($input, $key_encrypted, $CALG_RC4)


            InputBox("Crypter", "Your Data Encrypted is", $result)
            InputBox("Crypter", "Your Key Encrypted is", $key_encrypted)

            GUISetState(@SW_SHOW)
        Case $Button2;Works as Intended, as it decrypts previously successful encrypted variables just fine.
            GUISetState(@SW_HIDE)

            $input = ""
            $input = InputBox("Crypter", "Enter the data to be decrypted.")


            $key = ""
            $key = InputBox("Crypter", "Enter the key to decrypt the data.")


            $result = ""
            $result = BinaryToString(_Crypt_DecryptData($input, Number($key), $CALG_RC4))


            InputBox("Crypter", "Your Data Decrypted is", $result)

            GUISetState(@SW_SHOW)
    EndSwitch
WEnd

 

 

Edited August 24, 2015 by CrypticKiwi

[BrewManNH]

You're trying to encrypt the data with the derived key, but instead you're using the key as the password, which is wrong. Then you're expecting the user to remember the password used to decrypt it. If you want to use DeriveKey, then use $CALG_USERKEY as the algorithm for the encryption and decryption and not RC4.

[EmilyLove]

Got it, it has to be  Number($Key) while recieving decryption input from inputbox

expandcollapse popup

#RequireAdmin
#include "crypt.au3"
#include "Date.au3"
#include <ButtonConstants.au3>
#include <GUIConstantsEx.au3>
#include <StaticConstants.au3>
#include <WindowsConstants.au3>
#include <MsgBoxConstants.au3>
#Region ### START Koda GUI section ### Form=
$Form1 = GUICreate("Form1", 154, 121, 192, 124)
$Label1 = GUICtrlCreateLabel("What would you like to do?", 8, 8, 141, 17)
$Button1 = GUICtrlCreateButton("Encrypt", 8, 40, 137, 25)
$Button2 = GUICtrlCreateButton("Decrypt", 8, 80, 137, 25)
#EndRegion ### END Koda GUI section ###
Global $key_encrypted = _Crypt_DeriveKey("1WSUJpOq1ca2H9DMRhs14iy3fI04IBFp", $CALG_RC4);Does not generate a working key. What's going on?
Global $date, $input, $data, $result, $key
GUISetState(@SW_SHOW)

While 1
    $nMsg = GUIGetMsg()
    Switch $nMsg
        Case $GUI_EVENT_CLOSE
            Exit
        Case $Button1;I assume works as Intended.

            GUISetState(@SW_HIDE)
            $date = ""
            $date = _DateDiff("s", "1970/01/01 00:00:00", _NowCalc())

            $data = ""
            $data = _Crypt_EncryptData($date, $key_encrypted, $CALG_RC4)

            $input = ""
            $input = InputBox("Crypter", "Enter the data to be encrypted.", $data)

            $result = ""
            $result = _Crypt_EncryptData($input, $key_encrypted, $CALG_RC4)


            InputBox("Crypter", "Your Data Encrypted is", $result)
            InputBox("Crypter", "Your Key Encrypted is", $key_encrypted)

            GUISetState(@SW_SHOW)
        Case $Button2;Works as Intended, as it decrypts previously successful encrypted variables just fine.
            GUISetState(@SW_HIDE)

            $input = ""
            $input = InputBox("Crypter", "Enter the data to be decrypted.")


            $key = ""
            $key = InputBox("Crypter", "Enter the key to decrypt the data.")


            $result = ""
            $result = BinaryToString(_Crypt_DecryptData($input, Number($key), $CALG_RC4))


            InputBox("Crypter", "Your Data Decrypted is", $result)

            GUISetState(@SW_SHOW)
    EndSwitch
WEnd

 

 

This works, Thank you very much CrypticKiwi

You're trying to encrypt the data with the derived key, but instead you're using the key as the password, which is wrong. Then you're expecting the user to remember the password used to decrypt it. If you want to use DeriveKey, then use $CALG_USERKEY as the algorithm for the encryption and decryption and not RC4.

Could you show me an example of how it needs to be use to work properly so I may learn from it? I copy pasted the example from the documentation and expanded it to my needs. I thought I did it correctly.