Script to encrypt and decrypt files. What is your opinion of this method.

[Morthawt]

I made this script and it does work, but coming from more skilled coders, what do you think to my coding choices/style? Anything redundant/sloppy/unoptimized? I know this is only a test for myself to test out the encryption, but it is functional and has more than that demo one they had on it. I coded this all from scratch. One thing I noticed though is if I decrypt an AES file with the wrong password, it flags an error yet does not flag an error if I do the same with RC4. Either thats a coding issue on my end or thats the AES system knowing it decrypted incorrectly due to a wrong password.

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#include <Crypt.au3>
#include <ButtonConstants.au3>
#include <GUIConstantsEx.au3>
#include <GuiStatusBar.au3>
#include <StaticConstants.au3>
#include <WindowsConstants.au3>
#include <file.au3>

Global $drive
Global $dir
Global $filename
Global $ext
Global $alg = $CALG_AES_256

#Region ### START Koda GUI section ### Form=
$Form1 = GUICreate("Form1", 291, 119, 192, 124)
$Label1 = GUICtrlCreateLabel("File Encryption and Decryption", 24, 16, 249, 24)
GUICtrlSetFont(-1, 12, 800, 0, "MS Sans Serif")
$encrypt = GUICtrlCreateButton("Encrypt a file", 24, 56, 75, 25, BitOR($WS_GROUP, $BS_DEFPUSHBUTTON))
$decrypt = GUICtrlCreateButton("Decrypt a file", 192, 56, 75, 25, $WS_GROUP)
$StatusBar1 = _GUICtrlStatusBar_Create($Form1)
$AES = GUICtrlCreateRadio("AES (Win XP and above)", 24, 38, 140, 17)
GUICtrlSetState(-1, $GUI_CHECKED)
$RC4 = GUICtrlCreateRadio("RC4", 194, 38, 128, 17)
GUISetState(@SW_SHOW)
#EndRegion ### END Koda GUI section ###

While 1
    $nMsg = GUIGetMsg()
    Switch $nMsg
        Case $GUI_EVENT_CLOSE
            Exit

        Case $encrypt
            Encryptfile()

        Case $decrypt
            Decryptfile()

        Case $RC4
            ;MsgBox(0,'','RC4')
            $alg = $CALG_RC4

        Case $AES
            ;MsgBox(0,'','AES')
            $alg = $CALG_AES_256


    EndSwitch
WEnd





Func Decryptfile()
    $openfile = FileOpenDialog('Choose file to decrypt', @MyDocumentsDir, 'All Files (*.*)', 3)
    If $openfile <> '' Then
        $pathsplit = _PathSplit($openfile, $drive, $dir, $filename, $ext)
        $password = InputBox('Password', 'Enter the password', '', '*')
        $key = _Crypt_HashData($password, $CALG_SHA1)
        $savefile = FileSaveDialog('Save as', @MyDocumentsDir, 'All Files (*' & $pathsplit[4] & ')', 16)
        $pathsplitsave = _PathSplit($savefile, $drive, $dir, $filename, $ext)
        If $pathsplitsave[4] <> $pathsplit[4] Then $savefile = $savefile & $pathsplit[4]

        If $savefile <> '' Then
            If $openfile <> $savefile Then
                _Crypt_DecryptFile($openfile, $savefile, $key, $alg)
                If @error Then MsgBox(0, 'Error', 'There was an errror.')
            Else
                MsgBox(0, 'Error', 'You cannot overwrite the original file with the new file. Save as a different name.')
            EndIf
        EndIf


    EndIf



EndFunc   ;==>Decryptfile







Func Encryptfile()
    $openfile = FileOpenDialog('Choose file to encrypt', @MyDocumentsDir, 'All Files (*.*)', 3)
    If $openfile <> '' Then
        $pathsplit = _PathSplit($openfile, $drive, $dir, $filename, $ext)
        $password = InputBox('Password', 'Enter the password', '', '*')
        $key = _Crypt_HashData($password, $CALG_SHA1)
        $savefile = FileSaveDialog('Save as', @MyDocumentsDir, 'File (*' & $pathsplit[4] & ')', 16)
        $pathsplitsave = _PathSplit($savefile, $drive, $dir, $filename, $ext)
        If $pathsplitsave[4] <> $pathsplit[4] Then $savefile = $savefile & $pathsplit[4]




        If $savefile <> '' Then
            If $openfile <> $savefile Then
                _Crypt_EncryptFile($openfile, $savefile, $key, $alg)
                If @error Then MsgBox(0, 'Error', 'There was an errror.')
            Else
                MsgBox(0, 'Error', 'You cannot overwrite the original file with the new file. Save as a different name.')
            EndIf

        EndIf

    EndIf



EndFunc   ;==>Encryptfile

[guinness]

Add #AutoIt3Wrapper_Au3Check_Parameters=-d -w 1 -w 2 -w 3 -w 4 -w 5 -w 6 to the top of your Script to see if all variables are declared correctly.

Edited May 7, 2011 by guinness