Two well-known computer security experts pulled down their works from the Internet this week for fear of being prosecuted under 1998's Digital Millennium Copyright Act. Along with the threatened lawsuit of Princeton computer-science professor Edward Felten, and the arrest of Russian encryption expert Dmitry Sklyarov, the incidents are the latest to point at what is quickly becoming a touchy environment for security experts. "When they started to arrest people and threaten researchers, I decided the legal risk was not worth it," said Fred Cohen, a well-known security consultant and a professor of digital forensics, who took his evidence-gathering tool--dubbed Forensix--off ...