Senior official says Britain exploring national Internet filter

LONDON — The head of Britain’s new cybersecurity agency says authorities are exploring the creation of a national Internet filter to block malicious software and rogue websites, a proposal that has raised eyebrows among Internet freedom advocates.

According to a text of his speech published Wednesday, Martin said the system would allow people to opt out — meaning that privacy and choice would be “hardwired into our program.”

Martin said rogue websites would be blocked using DNS filtering, a venerable if clumsy censorship technique that prevents Internet users from reaching certain servers when they click a link or type out a Web address.

London’s Open Rights Group worried that the Cyber Security Center’s parent agency, Government Communication Headquarters, risked tampering with the integrity of the Internet.