New Scientist, 24 February 1996: "Trick of the light fools forgers." Researchers at U-Conn Storrs are developing security systems that use a new kind of invisible code -- the phase of light. A transparent phase mask over a photo on a credit card would make it very difficult to forge. The authenticity of the card is checked by a reader composed of a laser light source and a device called an optical correlator. Bahram Javidi, leading Storrs researcher, will publish the latest findings in SPIE proceedings, called "Optical Security and Counterfeit Deterrent Techniques" (v 2659). "Good connections, quantum style." For quantum computers of the future, any "noise" in the connection between sender and receiver could prove disastrous. The problem is that the data in such computers will be held in the form of individual photons and, since quantum theory states that they cannot be checked because the mere act of measuring them will transform them, every error that creeps in will go uncorrected. Now IBM researchers have come up with a way to make the connection crystal clear (PRL, v 76, p 722). [Cf. recent thread "IBM's Breakthrough."] PHO_ton