Looking for a better way to locate BitLocker Rec Key

[mdwerne]

Hello,

Currently I'm using the following code to allow a user to select a BitLocker recovery key file, and then decrypt a drive.

Func GetKey()
    ; Create a constant variable in Local scope of the message to display in FileOpenDialog.
    Local Const $sMessage = "Select the BitLocker Key File."

    ; Display an open dialog to select a file.
    Local $sFileOpenDialog = FileOpenDialog($sMessage, @DesktopCommonDir & "\", "Bitlocker Key File (*.txt)", $FD_FILEMUSTEXIST)
    If @error Then
        ; Display the error message.
        MsgBox($MB_SYSTEMMODAL, "", "No file was selected.")
    Else
        Local $sFileRead = FileRead($sFileOpenDialog)
        ;MsgBox($MB_SYSTEMMODAL, "", $sFileRead)
        Local $iPosition = StringTrimLeft($sFileRead, "378")
        $iPosition = StringTrimRight($iPosition, "239")
        MsgBox($MB_SYSTEMMODAL, "", $iPosition)
        GUICtrlSetData($sRecoveryKey, $iPosition)
    EndIf
EndFunc   ;==>GetKey

I'd like to improve this code in a couple possible ways:

1) Use a REGEX "^[0-9]{6}-[0-9]{6}-[0-9]{6}-[0-9]{6}-[0-9]{6}-[0-9]{6}-[0-9]{6}-[0-9]{6}$" to locate the recovery key, no matter where it is in the file, and then set the input field with the matched key.

or maybe...

2) Use REGEX again, and create a combobox with all the numbers in the file that match the pattern...just in case there is more than one match.

The 48bit recovery key is always in this format: "000000-000000-000000-000000-000000-000000-000000-000000"

Any suggestions as to how I might proceed?

Thanks,

-Mike

[kylomas]

mdwerne,

I might do it like this...

expandcollapse popup

; script requires 3.3.10+

#include <FileConstants.au3>
#include <MsgBoxConstants.au3>
#include <GUIConstantsEx.au3>
#include <array.au3>
#include <GuiComboBox.au3>
#include <ComboConstants.au3>

_create_test_file()

Local $gui010 = GUICreate('BitLocker Key Test', 600, 200)
Local $sRecoveryKey = GUICtrlCreateCombo('', 20, 20, 330, 100, $cbs_dropdownlist)
_GUICtrlComboBox_SetCueBanner($sRecoveryKey, "Select a Recovery Key")
GUICtrlSetData($sRecoveryKey, GetKey())

GUISetState()

While 1
    Switch GUIGetMsg()
        Case $GUI_EVENT_CLOSE
            Exit
        Case $sRecoveryKey
            ConsoleWrite('Recovery key selected = ' & GUICtrlRead($sRecoveryKey) & @LF)
    EndSwitch
WEnd

Func GetKey()

    ; Create a constant variable in Local scope of the message to display in FileOpenDialog.
    Local Const $sMessage = "Select the BitLocker Key File."

    ; Display an open dialog to select a file.
    Local $sFileOpenDialog = FileOpenDialog($sMessage, @ScriptDir & "\", "Bitlocker Key File (*.txt)", $FD_FILEMUSTEXIST)
    If @error Then
        ; Display the error message.
        MsgBox($MB_SYSTEMMODAL, "", "No file was selected.")
    EndIf

    Local $ret = StringRegExp(FileRead($sFileOpenDialog), '(?:\d{6}-){7}\d{6}', 3), $tstr

    Switch @error
        Case 0
            For $1 = 0 To UBound($ret) - 1
                $tstr &= '|' & $ret[$1]
            Next
            Return $tstr
        Case 1
            ConsoleWrite('No matches' & @LF)
            Exit
        Case 2
            ConsoleWrite('Bad pattern at offset ' & @extended & @LF)
            Exit
    EndSwitch

EndFunc   ;==>GetKey

; -----------------------------------------------------------------------------------------------------------------------------
;
; functions used to create test file
;
; -----------------------------------------------------------------------------------------------------------------------------

Func _create_test_file()
    Local $str, $FilePath = @ScriptDir & '\bitlocker.txt'
    For $1 = 1 To 10
        For $2 = 1 To 5
            $str &= (Mod($2, 2) = 0) ? _garbage() : _bitlockerpattern()
        Next
    Next
    FileDelete($FilePath)
    FileWrite($FilePath, $str)
EndFunc   ;==>_create_test_file

Func _garbage()
    Local $tstr = ''
    For $1 = 1 To Random(1, 50, 1)
        $tstr &= Chr(Random(1, 256, 1))
    Next
    Return $tstr
EndFunc   ;==>_garbage

Func _bitlockerpattern()
    Local $tstr = ''
    For $1 = 1 To 8
        For $2 = 1 To 6
            $tstr &= Random(0, 9, 1)
        Next
        $tstr &= '-'
    Next
    Return $tstr
EndFunc   ;==>_bitlockerpattern

The gui is rough and proof of concept only.

I dreamed up a test file consisting of junk with valid keys interspersed throughout since you did not provide an example.

kylomas

[mdwerne]

Well I searched and searched but sadly could not find an emoticon that depicted a jaw dropping to the floor...that is how I feel about your example...this is exactly what I was after. The extra step to create the test file shows me just how much I still have to learn, and why this application, the forum, and its members are the best!!

Thanks kylomas for taking the time to help me out, I really appreciate your effort.

-Mike

[kylomas]

No problem, glad to help.

In the future please remember to provide as much pertinent data as possible.  SRE's require a complete sample of input data and expected results.