#input masking

We decided that using ncurses wasn't the best idea, so I wrote up this solution and included a conio.h solution for Windows.

#ifdef _WIN32 #include #else #include #endif std::cout << "Enter PIN: "; #ifdef _WIN32 for (unsigned int i = 0; i < 4; ++i) { pin[i] = _getch(); std::cout << "*"; } #else static struct termios old_t, new_t; tcgetattr(STDIN_FILENO, &old_t); new_t = old_t; new_t.c_lflag &= ~(ECHO) & ~(ICANON); tcsetattr(STDIN_FILENO, TCSANOW, &new_t); for (unsigned int i = 0; i < 4; ++i) { pin[i] = getchar(); putchar('*'); } tcsetattr(STDIN_FILENO, TCSANOW, &old_t); #endif pin[4] = '\0'; std::cout << std::endl;

Basically for termios you grab a struct describing the terminal settings and set the flag to not include ECHO.  ICANON is the flag describing if everything is in "canonical mode." In my case, since the flag is set by default, it was causing the inputs to be stored in a buffer until a newline/return character was detected.

Woo! Magic!  Just doing masked PIN input in the terminal for a crypto project.

void readPin(char (&pin)[5]) { initscr(); noecho(); for (unsigned int i = 0; i < 4; ++i) { pin[i] = getch(); addch('*'); } endwin(); pin[4] = '\0'; }