Computer users dream of security software that provides perfect but invisible protection against hackers and other cybercriminals.

This fantasy program never slows your computer down or asks you annoying questions. It just works in the background.

Dave DeWalt would love to sell it to you, but seven months after taking the helm of computer security firm McAfee, he knows he'll never sell you anything quite that good.

"Every time the good guys figure out how to defend against one kind of attack, the bad guys think up something else," he said. "There will never be one perfect defense. There will only be an endless arms race."

The first computer virus appeared in 1982, when 15-year-old Richard Skrenta wrote a program designed to annoy his friends. The code embedded itself in Apple II computers but did nothing more than display taunt-laden poems after every 50 start-ups.

"It will get on all your disks/ It will infiltrate your chips/ Yes it's Cloner!"

As late as last year, McAfee technicians saw 30 to 50 new forms of malware a day, but the figure has since grown tenfold.

Mr. DeWalt explains the growth in terms of risk vs. reward.

"Total global profits from cybercrime now exceed total global profits from illegal drug sales, and it's a much safer business," Mr. DeWalt said.

"Most countries devote major resources to finding and jailing drug dealers but spend almost nothing on cybercrime. Which business would you choose?"

With or without the tougher legislation he has been lobbying for here and abroad, Mr. DeWalt thinks security companies can take several steps to better protect customers.

For example, rather than waiting for users to download something, new programs from McAfee and other security firms warn users of phony Web sites and other potential problems.

Programs that monitor Web sites should help users avoid phishing attacks – like those e-mails from fake banks that want you to verify the personal info they have in their accounts.

"We already have software that knows if you're actually at your bank's Web site or if you're at a decoy," Mr. DeWalt said. "And it keeps getting better at warning people away from potential problems."

Another big security initiative revolves around data encryption.

"As more and more people use wireless Internet connections, we will introduce better and better products for encrypting that information and preventing others from intercepting it," Mr. DeWalt said, noting that encryption would also reduce the potential damage from lost and stolen computers.

The more Mr. DeWalt discusses potential dangers, the more his listeners despair of ever buying enough protection.

Current dangers clearly demand an anti-virus program, a spybot sweeper, a Web monitor, a data encoding engine and God knows how many other programs.

Or do they?

"No one has the time and energy to research security product by product. They want a one-stop solution, and we're all trying to provide it," Mr. DeWalt said.

"That's why you see so much consolidation in the security industry," he said. "We're all trying to plug holes."

McAfee has already made significant strides toward that comprehensive package, particularly in its line of consumer products.

Rather than selling each of its programs separately, the company features three big bundles: 6 in 1 Protection, 10 in 1 Protection and 12 in 1 Protection.

None of them will live up to your dreams of invisible protection.

They'll always slow your computer down and ask you whether you really want to visit a particular Web site or to download a particular program.

That said, they're easier than their predecessors and offer you protection against millions of attacks.