In Windows, how do you enter ASCII characters that are not displayed on a keyboard?

In Windows, how do you enter ASCII characters that are not displayed on a keyboard?

Ctrl-Alt + keyboard keys corresponding to ASCII

Alt + ASCII decimal value on number pad

Shift-Alt + keyboard keys cooresponding to ASCII

Alt + ASCII decimal value using keyboard top 

 

EXPLANATION

I have used Alt + ASCI decimal value entered on the number pad for many years for various reasons.  It's a nice way to hide characters in passwords or files you want to keep secure. A password with an Alt-255 (null) character will display as a space and baffle even the most experienced hacker. While working in a public school system, my remote software client was VNC and it stored the password in hexidecimal format in the registry which above average students might
possibly be able to decode. But when ASCII 255 characters are found, they're totally confused. I have also named programs and batch files with just the null character plus extension to make it hidden.  I have also used ASCII extended box and line characters to make things look nicer in batch programs, but is limited with newer versions of Windows that lack ANSI.sys not being standard (it can be enabled).

SOURCE

https://support.office.com/en-us/article/insert-ascii-or-unicode-latin-based-symbols-and-characters-d13f58d3-7bcb-44a7-a4d5-972ee12e50e0