Anyone with access to a lock and key can easily create a master key. An AT&T Labs researcher has discovered that most master-key lock systems are vulnerable. NY Times (reg. req'd) reports that the technique is known, but not widely known. For instance, it does not appear in the ubiquitous document formerly known as the MIT Guide to Lockpicking. The AT&T Labs-Research paper is troubling some security experts, one of whom said that the "technique could open doors worldwide for criminals and terrorists." Because publishing the paper "could lead to an increase in thefts and other crimes, it presented an ethical quandary" for the researcher (Matt Blaze) and AT&T Labs-Research.