The cursor blinks. Input flows from the keyboard, raw and unguarded. Sensitive data appears on the screen, waiting for a mask that never slips.
Ncurses data masking is the simplest way to protect input in a terminal UI. Ncurses is a widely used C library for text-based interfaces. It lets developers control input, cursor movement, color, and screen layout without relying on GUIs. Data masking in Ncurses means replacing typed characters—like passwords, API keys, or tokens—with placeholder symbols. The real values stay in memory but are never shown to the screen.
To implement Ncurses data masking, initialize Ncurses with initscr() and turn off line buffering using cbreak(). Disable echo with noecho() to prevent characters from displaying as typed. In the input loop, capture each keystroke using getch(). For every printable character, append it to a secure buffer and print a mask symbol instead. Handle backspace by removing the last character from the buffer and repositioning the cursor with move(). On enter, terminate the loop and process the secured input.
Mask symbols are commonly asterisks, but you can choose any single byte character. Keep the masking display logic fast and avoid unnecessary screen refreshes with refresh() only when needed. For stronger security, overwrite the buffer in memory when done.