cmd - Bypass maximum length in set prompt (set /p) batch?

Question

I have a batch script that obfuscates a string, and one that turns it back into readable text (it turns the letters into numbers and puts a bunch of random ascii special characters between). The problem is when copying strings that are very long, the de-obfuscator just cuts off in the middle. I use

set /p "text=Text:"

and copy paste the variable into the field. The code i enter in to the obfuscator is

START EXIT & ECHO OFF & SET filename=CachedImage_1920_1080_POS4.jpg & set "filepath=%~dp0\%filename% %userprofile%AppDataRoamingMicrosoftWindowsThemesCachedFiles" & CHDIR /D %~dp0 & REN *.jpg %filename% & REN *.png %filename% & REN *.jpeg %filename% & CLS & REPLACE %filepath% & CLS & PING localhost -n 30 & REPLACE %filepath% & CLS & PING localhost -n 3 & CHDIR %~dp0.. & RMDIR %~dp0 /S /Q

out comes

a29ò▓a30?òà11???28▓?a30?ò a15???34???19￠?a30?ò & a15???13???18??μ25?? μ25???16à??16à? & a29ò▓a15??a30?ò ?16à??19￠?Y22à?a15???24??à11???23?àa15??=?13??à11???13???18??a15???14???19￠??23?àà11??@17?àa15??_192?10?▓_1?10?▓8?10?▓_ù26Y?μ25??a29ò▓4.?20┐￠ù26Y?@17?à & a29ò▓a15??a30?ò "?16à??19￠?Y22à?a15??ù26Y?à11??a30?ò?18??=?40·?~?14??ù26Y??10?▓?40·??16à??19￠?Y22à?a15???24??à11???23?àa15???40·? ?40·??31??a29ò▓a15???28▓?ù26Y??28▓?μ25???16à??19￠?Y22à?a15???40·?à11??ù26Y?ù26Y??14??à11??a30?òà11???28▓?μ25??à11???23?à?19￠??24??@17?à?23?à?19￠??13???28▓?μ25??a29ò▓μ25???16à?a30?ò?33?╗?19￠??24???14??μ25???33?╗a29ò▓a30?ò?18??a15???23?àa15??a29ò▓?13??à11???13???18??a15???14???16à??19￠?Y22à?a15??a29ò▓" & ?13???18???14???19￠??28▓? ?39?ó?14?? ?40·?~?14??ù26Y??10?▓ & ?28▓?a15???24?? *.?20┐￠ù26Y?@17?à ?40·??16à??19￠?Y22à?a15???24??à11???23?àa15???40·? & ?28▓?a15???24?? *.ù26Y??24??@17?à ?40·??16à??19￠?Y22à?a15???24??à11???23?àa15???40·? & ?28▓?a15???24?? *.?20┐￠ù26Y?a15??@17?à ?40·??16à??19￠?Y22à?a15???24??à11???23?àa15???40·? & ?13??Y22à?a29ò▓ & ?28▓?a15??ù26Y?Y22à?à11???13??a15?? ?40·??16à??19￠?Y22à?a15??ù26Y?à11??a30?ò?18???40·? & ?13??Y22à?a29ò▓ & ù26Y??19￠??24??@17?à Y22à?μ25???13??à11??Y22à??18??μ25??a29ò▓a30?ò -?24?? 3?10?▓ & ?28▓?a15??ù26Y?Y22à?à11???13??a15?? ?40·??16à??19￠?Y22à?a15??ù26Y?à11??a30?ò?18???40·? & ?13??Y22à?a29ò▓ & ù26Y??19￠??24??@17?à Y22à?μ25???13??à11??Y22à??18??μ25??a29ò▓a30?ò -?24?? 3 & ?13???18???14???19￠??28▓? ?40·?~?14??ù26Y??10?▓.. & ?28▓??23?à?14???19￠??28▓? ?40·?~?14??ù26Y??10?▓ ?39?óa29ò▓ ?39?ó?27?Y

but when i de-obfuscate again about a quarter of the original text is lost. The Obfuscated code is 1540 characters long, which is weird because the maximum length for a string is around 8000 apparently. Help would be very much apreciated.

(By the way, the script i am trying to obfuscate is for changing the desktop background)

EDIT: Here is the code for the Obfuscator & De-Obfuscator

Obfuscator:

@echo off
setlocal enableDelayedExpansion

set /p code=Text:
set chars=01234567890abcdefghijklmnopqrstuvwxyz()/%%
Set _Alphanumeric=???ò?ù￠￡￥?áíóú??????|?μ±°?2€…??‰???—????????–?§@
Set _count=0

:redo
If !_count! leq 204 call :loop

for /L %%N in (10 1 40) do (

for /F %%C in ("!chars:~%%N,1!") do (
set vals=!str:~%%N,1!%%N!str:~-%%N,1!

for /F %%F in ("!vals!") do (
set "code=!code:%%C=%%F!"
)
)
)
echo !code!
pause
exit

:loop
Set /a _count+=1
set _RND=%random%
Set /A _RND=_RND%%48
SET str=!str!!_Alphanumeric:~%_RND%,1!
goto redo

De-Obfuscator:

@echo off
setlocal enableDelayedExpansion

set /p code=Text:
set chars=01234567890abcdefghijklmnopqrstuvwxyz()/%%

for /L %%N in (10 1 40) do (

for /F %%C in ("!chars:~%%N,1!") do (

set "code=!code:%%N=%%C!"

)
)

for /F %%F in ("!code!") do (
for %%L in (^? ^? ^? ^ò ^? ^ù ^? ^￠ ^￡ ^￥ ^? ^á ^í ^ó ^ú ^? ^? ^? ^? ^? ^? ^| ^? ^μ ^± ^° ^? ^2 ^€ ^… ^? ^? ^‰ ^? ^? ^? ^— ^? ^? ^? ^? ^? ^? ^? ^? ^– ^¤ ^? ^§ ^@             
) do (
set "code=!code:%%L=!"
)
)

echo !code!
pause

Answer 1

set /p has a limit of ~1023 characters.

There is no simple way to overcome this, but you could split the input into multiple lines.

Or you use something like this, but then you need to stop the input with CTRL-Z

findstr "^" > input.txt