MONTREAL - The U.S. secretary of homeland security says privacy is not sacrificed with security measures designed to thwart potential terrorists.

Michael Chertoff said Wednesday that measures to create secure ID and screen people entering the United States actually improve privacy.

"I want to reject the implicit zero-sum premise that privacy must be traded for security," Chertoff said at a privacy conference in Montreal.

It's not the case "that one has to win and one has to lose," he said.

Instead of "flipping a coin" to pick travellers who should face extra screening, Chertoff said it's better to collect a small amount of personal information on the 80 million people who fly into the United States each year.

Chertoff said the collection of small amounts of personal data on U.S.-bound travellers has "proven, concrete" value.

He gave examples of travellers who were rejected entry and later were found to have links to bombings in Iraq and other plots.

He says upcoming passport requirements for Canadians to enter the U.S. at land crossings are needed to narrow down the 8,000 worldwide pieces of ID that have been accepted.

Chertoff said that new secure identification will help prevent identity theft.

While some debate has taken place in Canada over the idea of a national ID card, Chertoff said Americans would never stand for it.

"Their heads would explode," he said.