Embed text in a file other than ".txt"

[wattexi]

Hello, I am looking for a way to "hide" text (a word) in a file of any type (the file will be corrupted and unusable ... it's ok), but after I would like to open the file extract my "word ", delete it from the file to" rebuild "it so that it becomes usable again.
I was thinking of using FileOpen's "$ FO_BINARY" mode but I can only open it !! I would need functions like: FileDataRead, FileDataApend, FileDataWrite ...
I'm blocking ... I'm looking for help or information ...
thank you in advance

[FrancescoDiMuro]

Hi @wattexi, and welcome to the AutoIt forums 
Why would you corrupt or let a file being corrupted?
Could you please explain the purpose of what you are trying to do, and maybe an example and your script.

[Melba23]

wattexi,

Yes, please do explain just why you want to "hide" something inside another file, thus corrupting it, and then extract it later while restoring the original file. A number of possible explanations come to mind - some of which I really do not like very much.

M23

P.S. And just to be absolutely clear - this is the Mod team determining the legality of the thread, so everyone else please keep out.

[wattexi]

my script does that:

select a file (.txt .rar .docx or other ...), isolate the extansion, encrypt the file (_Crypt_EncryptFile)

I want to integrate the extension of the original file into the encrypt file, for another script then decrypt (_Crypt_DecryptFile) the file and  renamed with good extansion.

Thanks for your help.

[Melba23]

wattexi,

That explains clearly what you want to do - now how about explaining why you want to do this.

M23

[wattexi]

Imagine a person encrypts a file type .xxx (for more security  the original extension does not appear in the file name encrypt) and send it to another person who owns the encryption key.
This second person can decrypt it and rebuild it if the script extracts the extension.
My "exercise" is already operational, it is the "hide" of the extension that annoys me, but if that is not possible, I think to do that by adding (to encrypt) the type of extension original in the file name encrypt ...

[wattexi]

But if someone changes the file name encrypt everything is on the floor ... Hello the fault 

[Melba23]

wattexi,

Thank you for that - happy for the thread to stay open.

M23

[careca]

You could encrypt the file as you do, but then grab the extension and hide it somewhere you choose inside the file.

The extension would be whatever you want, but the real extension would be hidden inside the file and recoverable because you know the offset where it would be.

Would something like this work for you? I did this for a similar purpose, the difference is that it doesn't really encrypt the file, only the filename and extension, the file data is scrambled, you just need to remember the pin, that pin will be the offset in bytes, oh well it's complicated to explain.

 

[wattexi]

yes that's what I want to do, but I'm in trouble about rebuilding the file:

If I transform the file, add text and re transform:
_FileReadToArray ($file_path, $array) > _ArrayAdd ($array, $text) > _FileWriteFromArray ($new_file_path, $array, 1)

during extraction and reconstruction:
_FileReadToArray ($new_file_path, $array) > _ArrayPop ($array) > _FileWriteFromArray ($new_new_file_path, $array, 1,3)

I find my text thanks to _ArrayPop ($array), my table looks correct (such as before adding text), but it is corrupt (the decryption is in error), a verif with notepad ++ gives the same characters encrypt but a "lenght" different (a @crlf in +)?

Edited January 6, 2019 by wattexi

[careca]

I dont know what to say... there's no code.

[wattexi]

sorry...

Edited January 6, 2019 by wattexi

[wattexi]

you want the complete code with the Gui, the select ...?

[wattexi]

expandcollapse popup

#include <File.au3>
#include <Array.au3>
#include <Crypt.au3>

#include <ButtonConstants.au3>
#include <EditConstants.au3>
#include <GUIConstantsEx.au3>
#include <StaticConstants.au3>
#include <WindowsConstants.au3>


$Form1 = GUICreate("Crypted", 230, 88, 192, 124)
$Button1 = GUICtrlCreateButton("Select file", 56, 18, 115, 49)
$Button2 = GUICtrlCreateButton("Encrypt", 120, 50, 89, 25)
$Input1 = GUICtrlCreateInput("", 88, 16, 121, 21, BitOR($GUI_SS_DEFAULT_INPUT,$ES_CENTER,$ES_PASSWORD))
$Label1 = GUICtrlCreateLabel("Pws =", 24, 20, 36, 17)
$Checkbox1 = GUICtrlCreateCheckbox("Show pws", 24, 54, 73, 17)
GUISetState(@SW_SHOW)


HotKeySet("{F5}","stop")
hide_elmts()

Global $file_crypted = False
Global $file_selected = ""
Global $extension, $file_path_without_extension

$algorithm = $CALG_AES_256


;Retrieve the ASCII value of the default password char
$sDefaultPassChar = GUICtrlSendMsg($Input1, $EM_GETPASSWORDCHAR, 0, 0)


While 1
    $nMsg = GUIGetMsg()
    Switch $nMsg
        Case $GUI_EVENT_CLOSE
            Exit
        Case $Button1
            select_file()
        Case $Button2
            encrypt_decrypt_file()

        Case $Checkbox1

            If GUICtrlRead($Checkbox1) = $GUI_CHECKED Then
                GUICtrlSendMsg($Input1, $EM_SETPASSWORDCHAR, 0, 0)
                GUICtrlSetData($Checkbox1, "Hide Psw")
            Else
                GUICtrlSendMsg($Input1, $EM_SETPASSWORDCHAR, $sDefaultPassChar, 0)
                GUICtrlSetData($Checkbox1, "Show Pws")
            EndIf

            GUICtrlSetState($Input1, $GUI_FOCUS)
            GUICtrlSetState($Button1, $GUI_FOCUS)

    EndSwitch
WEnd


Func select_file()

    $file_selected = FileOpenDialog("Select file",@DesktopDir,"All (*.*)");"Text files (*.txt)"

    If @error Then

        MsgBox(16, "", "No file selected.")
        stop()
    EndIf

    ;MsgBox(0,"",$file_selected)

    $arrayay_file_path = StringSplit($file_selected,".")
    ;MsgBox(0,"",$arrayay_file_path[2] &@CRLF& $arrayay_file_path[1])

    $file_path_without_extension = $arrayay_file_path[1]
    $extension = $arrayay_file_path[2]

    If $extension = "crypted" Then
        GUICtrlSetData($Button2, "Decrypt")
        $file_crypted = True
        show_elmts()
    Else
        GUICtrlSetData($Button2, "Encrypt")
        $file_crypted = False
        show_elmts()
    EndIf

EndFunc


Func encrypt_decrypt_file()

    $file = $file_selected ; Read the source filepath input.
    $psw = GUICtrlRead($Input1) ; Read the password input.

    If StringStripWS($file, 8) <> "" And StringStripWS($psw, 8) <> "" And FileExists($file) Then ; Check there is a file available to encrypt and a password has been set.

        If $file_crypted = False  Then

            $new_file_path = $file_path_without_extension & ".crypted"

            If _Crypt_EncryptFile($file, $new_file_path, $psw, $algorithm) Then ; Encrypt the file.

                local $array
                _FileReadToArray($new_file_path,$array)
                ;_ArrayDisplay($array)
                _ArrayAdd($array, $extension)
                ;_ArrayDisplay($array)
                _FileWriteFromArray($new_file_path,$array,1)

                MsgBox(0, "Success", "Operation succeeded.")
            Else
                Switch @error
                    Case 1
                        MsgBox(16, "Error", "Failed to create the key.")
                    Case 2
                        MsgBox(16, "Error", "Couldn't open the source file.")
                    Case 3
                        MsgBox(16, "Error", "Couldn't open the destination file.")
                    Case 4 Or 5
                        MsgBox(16, "Error", "Encryption error.")
                EndSwitch
            EndIf

        Else

            $new_file_path = $file_path_without_extension & ".txt"
            If FileExists($new_file_path) Then
                $new_file_path = $file_path_without_extension & "_decrypted.txt"
            EndIf

            local $array
            _FileReadToArray($file,$array)
            _ArrayPop ($array)
            ;_ArrayDisplay($array)
            _FileWriteFromArray($file,$array,1,3)

            If _Crypt_DecryptFile($file, $new_file_path, $psw, $algorithm) Then ; Encrypt the file.
                MsgBox(0, "Success", "Operation succeeded.")
            Else
                Switch @error
                    Case 1
                        MsgBox(16, "Error", "Failed to create the key.")
                    Case 2
                        MsgBox(16, "Error", "Couldn't open the source file.")
                    Case 3
                        MsgBox(16, "Error", "Couldn't open the destination file.")
                    Case 4 Or 5
                        MsgBox(16, "Error", "Decryption error.")
                EndSwitch
            EndIf

        EndIf

    Else
        MsgBox(16, "Error", "Please ensure the relevant information has been entered correctly.")

    EndIf

EndFunc




Func hide_elmts()
    GUICtrlSetState($Label1,32)
    GUICtrlSetState($Input1,32)
    GUICtrlSetState($Checkbox1,32)
    GUICtrlSetState($Button2,32)
EndFunc

Func show_elmts()
    GUICtrlSetState($Button1,32)
    GUICtrlSetState($Label1,16)
    GUICtrlSetState($Input1,16)
    GUICtrlSetState($Checkbox1,16)
    GUICtrlSetState($Button2,16)
EndFunc



Func stop()
    Exit
EndFunc

_FileWriteFromArray($file,$array,1,3) => is for test, i know the array size with _ArrayDisplay($array). I make test with a little txt file with somme text...

Edited January 6, 2019 by wattexi

[BrewManNH]

If you want to embed this file inside another file, use the NTFS ADS (alternate data streams). There are examples of how to do this in the forum, and I linked to a google search that should give you choices.

[wattexi]

ok thanks