The free-of-charge Opera 9.1 relies on PhishTank, an open source-style project whose members submit suspicious URLs, then verify scams, and share the resulting blacklists. PhishTank is run by OpenDNS.
Opera's new Fraud Protection feature also is powered by technologies from GeoTrust, a VeriSign-owned company that specializes in digital signature verification.
"Cybercriminals are very active during the holiday season as more people venture online to shop or connect with friends and family," said Jon von Tetzchner, Opera's chief executive, in a statement. "We commit a lot of resources to ensure that our users are as safe as possible when they are online."
Opera debuted a basic phishing feature in version 8, which used the address field to show whether a site's certificate was legitimate. The new tools in 9.1, however, operate in real-time, said the Oslo-based company. Other changes to 9.1 include stability and performance improvements, easier RSS newsfeed deletions, and better handling of site logins over slow connections.