A glossary of important technical terms in combating child pornography on the Internet:
Data retention: Internet providers retain a small amount of user data for days, weeks or sometimes a few months. Europe requires six months to two years of data retention, including content and places a user visited on the Internet. The Bush administration proposes six months but no content retained.
IP address: The Internet protocol address, four sets of numbers separated by dots, is usually assigned by Internet service providers to a computer connecting to the Internet. The number is unique to the user and often identifies him or her by region. This is what law enforcement wants retained.
MAC address: Media access control addresses are unique identification numbers for the networking device on a computer that connects to the Internet. If detectives can't easily trace an IP address, they try to trace a MAC address back to the purchase or registration of the computer, or compare it with other places the address appears on the Internet.
Spoofing: This is when computer users usurp the IP or MAC addresses of someone else. They hide their identities to gain unauthorized access to restricted data or to conduct illicit activity online. Dozens of spoofing software programs are available on the Internet.
File sharing: Server-based Web sites that sell child pornography are few and far between these days. The illicit trade now happens through file sharing in peer-to-peer networks, which allow computer users to connect directly to each other instead of through a central server.