Local $lEncr = _Encrypt( "Daniel W.", "Passwort", 1 )
Local $lDecr = _Encrypt( $lEncr, "Passwort", 0 )

MsgBox( 0, "Test", $lEncr & @CRLF & $lDecr )

;===============================================================================
;
; Function Name:   _Encrypt( $aString, $aPW ,$aMode = 1 )
; Description::  Function to en- decrypt strings
; Parameter(s):  $aString = String to encrypt
;                $aPW = Password
;                $aMode = 1 for encrypt, 0 for decrypt
; Requirement(s):  None
; Return Value(s): en- decrypted string
; Author(s): Daniel Wahlmann
;
;===============================================================================
;

Func _Encrypt( $aString , $aPW, $aMode = 1 )	
	Local $lReturn = "",$lBuffer = "", $lPW = "", $lStrLen = StringLen( $aString ), $lPwLen = StringLen( $aPW )
	If Not IsString( $aString ) or $lStrLen < 1 or ($aMode <> 0 and $aMode <> 1) or ($aMode = 0 and Mod( $aString, 2 ) <> 0 ) or StringLen( $aPW ) < 1 Then Return 0
	For $lNum = 1 to $lPwLen
		$lPW &= Asc( StringMid( $aPW , $lNum, 1 ) )
	Next
	Switch $aMode
		Case 1
			For $lNum = 1 to $lStrLen
				$lReturn &=  Hex( BitXOR( BitNOT( Asc( StringMid( $aString, $lNum, 1 ) ) + 1 ), $lPW, 255 ), 2 )
			Next
		Case 0
			For $lNum = 1 To $lStrLen
				$lBuffer &= Chr( BitXOR( BitNOT( Asc ( Chr( Dec( StringMid( $aString, $lNum, 1 ) & StringMid( $aString, $lNum + 1, 1 ) ) ) ) ), $lPW, 255 ) )
				$lNum += 1
			Next
			For $lNum = 1 to $lStrLen/2
				$lReturn &=  Chr( Asc( StringMid( $lBuffer, $lNum, 1 ) ) - 1 )
			Next
	EndSwitch
	Return $lReturn
EndFunc   ;==>_Encrypt

;===============================================================================
;
; Function Name:   _EncryptFile( $aFile, $aPW ,$aMode = 1 )
; Description::  Function to en- decrypt files
; Parameter(s):  $aFile = file to encrypt/decrypt
;                $aPW = Password
;                $aMode = 1 for encrypt, 0 for decrypt
; Requirement(s):  File.au3
; Return Value(s): Success 1
;                  Failure 0
; Author(s): Daniel Wahlmann
;
;===============================================================================
;

Func _EncryptFile( $aFile, $aPW, $aMode = 1 )
	Dim $lRead, $lReturn = False
	If FileExists( $aFile ) Then
		_FileReadToArray( $aFile, $lRead )
		FileDelete( $aFile )
		For $lNum = 1 to $lRead[0]
			FileWriteLine( $aFile, _Encrypt( $lRead[$lNum], $aPW, $aMode ) )
		Next
		$lReturn = True
	EndIf
	Return $lReturn
EndFunc   ;==>_EncryptFile