SAN FRANCISCO - There is a dark side to the Internet, and it can be used for evil as well as for good.
A massive online bazaar hawking narcotics, weapons, forgeries, and other illicit items or services operated openly for years by relying on tools designed to safeguard privacy or foster a new world of Internet commerce.
Underground website Silk Road was seized by US authorities this week and its accused mastermind Ross William Ulbricht is to appear in federal court in San Francisco on Friday to determine whether he should remain in custody while the criminal case against him proceeds.
"Every technology has almost immediately been used to do bad things," said Alex Stamos, chief technology officer at Artemis Internet, which specializes in online security.
"People are going to do illegal stuff, but it turns out that it is really tough to run an eBay for drugs and not get caught."
Silk Road thrived on the principle that assurances of anonymity would free sellers and buyers to engage in transactions barred by law or frowned upon by society.
To accomplish this, Silk Road combined a Tor network for being invisible online with Bitcoin digital currency that can be as difficult to trace as cash trading hands in a dark alley.
"Part of the reason for the site's longevity is that it was hosted as a hidden service on the Tor network," Trend Micro security threat researcher Robert McArdle explained in a blog post.
Free Tor software lets people wrap data such as messages, website visits, or online transactions in layers of protection including encryption and then bounce it about machines in a worldwide peer-to-peer network to cover trails.
Each machine along the way only peels back a slight layer; enough to send the data to its next point in a journey.