Chemists in Israel have designed a molecule that can process a password in a manner similar to electronic keypads found in home security systems. The molecular lock, which resembles an iron-binding compound secreted by bacteria, “opens” when a combination of ultraviolet light and two chemical signals activates its fluorescent molecules. Information carried via the glowing molecules could thereby authorize a user or trigger another process. Because the molecular keypad relies on fluorescence, it can operate on the level of a single molecule. Moreover, molecules would build up from more than one password attempt, causing the lock to jam and block further tries. The researchers suggest the device could be used, along with current molecule-based cryptography methods, to protect high-security information. The data would be safe even if an unauthorized individual knew the lock's location and the decryption keys. They published their work in the January 17 Journal of the American Chemical Society.