To explain a bit more about the complete project:
The main thing is to have a Seeeduino-XIAO to act as a access-key by connecting its USB-C-Port to windows-computers
accessing a web-based email which is only accessabe through a browser.
( absolutely NO chance to use thundebird or something similar)
accessing the emails requieres entering a loooong email-adress that can't be changed
entering a passwort with minimum 12 characters
entering a TOTP-token based on a key that is only available as base32-encoding
normally this means:
call web-interface
type in by hand looooong email-adress
type in by hand password
start WinAuth or pick up the smartphone to start Google-Authenticator
read TOTP-token or copy TOTP-token to clipboard
type or paste TOTP-token into webinterface.
And most of this shall be done by the XIAO
call web-interface
plug in XIAO
XIAO does the login-details
I don't want to discuss if this is secure enough or not.
(it requires to have this particular XIAO)
additionally I want to implement a function on the XIAO that enables
sending the XIAO the base32-encoded key over serial interface.
The Arduino TOTP-library requires to have the key as ASCII-coded byte-array.
And this is the reason why I need base32-to ASCII-code-conversion
As the key shall be changeable on the run-time-level workarounds like using
a web-based conversion-tool and modify the source-code is not a solution.
So this are the main facts and requirements for this project.
If somebody can provide an easier to use solution for this go ahead and post a link
best regards Stefan