Earlier in the week we wrote about BitCoin, a type of untraceable internet currency, and the controversy it has sparked by attracting users in less-than-legal pursuits.

Today Ars Technica reported that an alleged theft of 25,000 BTC, holding a current value of around half a million dollars, had occurred. "Whether the story is true or not, it highlights a major disadvantage of the currency's much-touted lack of intermediaries. Bypassing middlemen frees users from government meddling and bank fees. But it also deprives them of the benefits those intermediaries provide, including protection against theft and fraud."

A user on the Bitcoin forums, allinvain, posted earlier in the week that a "very large chunk" of bitcoins had been stolen.

Ars Technica said the authenticity of the theft would be difficult to confirm, according to Gavin Adresen, leader of the Bitcoin software project.

"Still, the kind of attack described in the post is certainly possible. Andresen says he always emphasizes that Bitcoin is an experiment, and not (yet) for the faint of heart. 'Unfortunately, this is an expensive test case for the guy who lost the Bitcoins,' he said."