Group of individuals interested in computer security, electronic gadgetry, communications, privacy, and technology exploration. Provides seminars, meetings, and mailing lists.

UK-based organization of hackers and phreaks. Site provides information on the group's projects, tours and conferences.

Hacker collective based in New York City. Site presents news, books, projects, events, and convention pictures.

Nonprofit organization dedicated to providing research and demonstration on network services' and communication security's weaknesses.