RSA Symantec's chief executive has lambasted Microsoft for a dangerous conflict of interest as both the provider of an operating system and seller of software designed to secure its users.

John Thompson effectively blamed Microsoft for damaging consumers' confidence in the internet by going it alone and providing its own security for Windows Vista.

Thompson drew applause from an audience of his peers at the RSA Conference in San Francisco, barely an hour after Microsoft's Bill Gates and chief research and strategy officer Craig Mundie opened the annual event in stately - if unexciting - fashion. Gates and Mundie said the challenge for the industry lays in protecting users of Windows Vista and Office 2007 against their own mistakes.

As with its Windows XP predecessor, which went on to be mercilessly hacked, Microsoft claims its latest operating system is its most secure yet. Microsoft has founded this claim on the Patchguard architecture once used in 64-bit editions of Windows XP, which grants only partial access to the Widows kernel, and on Windows Live OneCare to keep PC users' anti-virus protection up to date.

Security vendors including Symantec, though, have criticized Patchguard for granting them only partial access to the Windows kernel and for leaving the job of protecting Windows against new threats to Microsoft. At best, Microsoft has an unproven track record in providing security software, while at worst Microsoft itself is seen as the very cause of the security problems in Windows.

Thompson said e-commerce risks not reaching its full potential if consumers continue to lack confidence in the online world.

Thompson stressed the need for co-operation between security companies and customers to build confidence by detecting threats and building secure systems, adding "no-one" company can secure the entire online world.

He didn't name Microsoft, but he didn't have to as he substituted the words "operating system" for "operating platform."

Thompson told RSA delegates: "You wouldn't want the company that is keeping your books to audit your books. The same logic should apply. You wouldn't want the company that created your company's operating platform to be the one that is securing it from a broad range of threats. It's a huge conflict of interest."

"We understand we are all in this together," he said.

Thompson was quoted in 2006 saying he was more concerned about Microsoft's lack of experience in security than the threat of potential competition to Symantec. The company last month, though, announced $200m in cost-cutting measures after warning revenue and profits will drop in the face of free and low-cost security products from companies like Microsoft.®