Imagine a computer that can detect an unauthorized user at the keyboard in the time it takes to read this sentence--in fact, by reading this sentence. And if reading doesn't do the trick, the computer may catch the intruder the good old-fashioned way, with fingerprints.

Professors at New Mexico State University have developed a software program that can identify a user by typing style. The software uses a tiny timing device to measure the intervals between keystrokes. Everyone has a unique typing rhythm; the software stores a computer user's personal rhythm profile and then locks out any user whose style is a bit off-key. The system can spot impostors nearly every time, claim its inventors. And unlike passwords, which open a computer to anyone once a legitimate user types one in, the typing watchdog stops anyone from taking over a keyboard if the rightful user steps away.

If having computer security at your fingertips appeals to you, here's something else to feel out: finger image identification. The National Registry (St. Petersburg, Fla., 813-573-3353); offers software for Windows and UNIX that works with a minicamera that captures and stores an image of a user's fingerprint. Anyone who wants to enter the system has to place his or her finger in front of the camera to pass muster. The software is already being used in various government agencies to screen out people who apply for welfare or other services under several different names.