Masking the user input as asterisks in Windows?

Question

I need to create a simple password program where the program asks user to input password and when user inputs, it shows the characters as asterisks.

Every tutorial out there uses getch() (in conio.h). But I don't want to use it. Is there any easy alternative for doing so?

I'm using Windows 10.

P.S: Please don't confuse this to be a duplicate of this question: Alternative function in iostream.h for getch() of conio.h?

Because that question asks for holding screen output whereas I need to mask the input as asterisks.

You can't do this with C++ standard library, you need platform specific APIs. So, which OS? — hyde, Oct 26 '19 at 13:39
https://stackoverflow.com/questions/1413445/reading-a-password-from-stdcin shows how to just silence echoing what user types. But you want to show astrixes, which makes this more complicated. — hyde, Oct 26 '19 at 13:42
@hyde yes, thanks for that link. It's useful to know how to silence the echo types but I still need to show asterisks :( — Zain Abedin, Oct 26 '19 at 13:50
So you need to figure out how to read unbuffered keyboard input in terminal. I think on windows you need to listen to keyboard events, then get the character from event and print asterisk. — hyde, Oct 26 '19 at 13:54
Well, I have no idea how to read to keyboard events except for getch. and I've been searching but it only shows getch (and curses which is in linux) so I guess there's no other way? — Zain Abedin, Oct 26 '19 at 13:59

score 2 · Answer 1 · answered Oct 26 '19 at 14:14

2

We are here in non standard functionality. So, whatever you'll do, it will not be portable.

The native console way would be to ReadConsoleInput() as explained here. In your case, you would first disable the echo and the line input mode by clearing the console mode flags ENABLE_LINE_INPUT and ENABLE_ECHO_INPUT. Then you would react on key events by displaying '*'. Don't forget to restore the inital console mode at the end.

A shortcut would be to just save and change the console mode (as shown in the code above), an then looping for cin.get() and echoing cout<<'*'; followed by cout.flush(); to be sure that the output doesn't wait in a buffer, creating discomfort for the user.

answered Oct 26 '19 at 14:14

Christophe

68,716
7
72
138

Alternatively, programs such as "runas.exe" call [`CredUICmdLinePromptForCredentialsW`](https://docs.microsoft.com/en-us/windows/win32/api/wincred/nf-wincred-creduicmdlinepromptforcredentialsw). It opens "CONIN$" and "CONOUT$" directly instead of using the standard handles. The flag `CREDUI_FLAGS_EXCLUDE_CERTIFICATES` is required, and you probably also want `CREDUI_FLAGS_DO_NOT_PERSIST`. If you have the user name already, you can pass it as `pszTargetName` (in addition to `UserName`) instead of passing a server name, in combination with the flag `CREDUI_FLAGS_USERNAME_TARGET_CREDENTIALS`. – Eryk Sun Oct 26 '19 at 18:16
However, `CredUICmdLinePromptForCredentialsW` does not show asterisks for typed input. – Eryk Sun Oct 26 '19 at 18:19

Masking the user input as asterisks in Windows?

1 Answers1

Linked

Related