Kaspersky Lab will quit the Business Software Alliance (BSA) from the first day of 2012, in protest against the BSA’s support for the Stop Online Piracy Act (SOPA).

SOPA is a proposed law that would extend the ability of copyright holders to protect their material from online exchange. It has been criticised by large internet companies such as Google, Facebook and Yahoo, while its supporters include Apple, Microsoft and SAP. SOPA was introduced to the US House of Representatives in October. The BSA has acknowledged that there are some issues with the proposed law, but remains supportive overall.

In a blog explaining the decision, CEO Eugene Kaspersky said that the "complete Americanisation" of SOPA was what bothered him.

Kasperksy noted that, because the proposed law only protects US copyright holders, and the large majority of DNS servers (which translate website names to IP addresses) are in the USA, non-US copyright holders will go unprotected from online piracy. "Under this law, the interests of non-American authors/creators are not protected at all, while the nationality of the perpetrators is of no importance," he wrote.

"Protecting the film/audio/software and other ‘intellectual’ industry interests by means of SOPA is like taxing email in favour of the State Postal Service, or forcing Skype to charge the same as the phone companies," Kaspersky added.

"If we accept this law, hundreds of thousands of lawyers will suddenly appear out of the woodwork because almost any website can be accused of copyright infringement. This law will lead to major legalised extortion."