London-listed Avast, which has grown through a "freemium" model of giving away its basic antivirus software and then selling additional services, said customers were increasingly aware of online risks.

"AntiTrack helps users to stop tracking from both advertisers and other data collectors," Chief Executive Ondrej Vlcek said in a interview.

"It makes it much harder for both advertisers and other entities that want to track you on the Internet to do that."

Avast has also seen strong demand for its high security browser, he said, with the number of active users rising to about 40 million. The company monetises the browser through search revenue and advertising, he said.

Shares in Prague-based Avast, which listed in May 2018, rose to a new high of 322 pence in early trade on Wednesday following its results.

The company reported a 9.2% rise in first-half adjusted revenue to $421.7 million (£349.6 million), ahead of a company-supplied consensus estimate of $414 million.

Adjusted core earnings rose 6.5% to $236.5 million, beating a forecast of $229 million.

Cyber security stocks have been boosted by chipmaker Broadcom's acquisition of antivirus software maker Symantec Corp's enterprise unit this month.

Vlcek said Avast was looking out for deals of its own. "We are constantly looking for opportunities," he said. "But there's nothing imminent."

(Editing by Deepa Babington and Jason Neely)

By Paul Sandle