John Adams, chief of Canada's little-known spy agency, the Communications Security Establishment, stressed in his first interview since taking the job in July that monitoring terrorists through cyberspace is as vital as tracking them on the ground.

That responsibility, plus monitoring all other forms of electronic communications and ensuring the security of the government's communications, falls to the CSE, which has quietly become one of Canada's most powerful agencies. With the exception of the Mounties, no other federal agency benefited more from the resources or powers doled out after the Sept. 11, 2001, terrorist attacks crumbled New York's twin towers.

By 2007, CSE's budget is expected to grow to $220 million, more than double what it received pre-9/11.

But some security experts are starting to challenge the effectiveness of such agencies — the Americans' National Security Agency among them — as well as Adams's assertion that signals intelligence will help fight terrorism. Today's terrorists have become so computer savvy and the world has become so saturated with technology that allows information to travel at a staggering speed since these agencies came of age more than half a century ago.

Others are concerned about privacy rights coming up against the government's ability to snoop and of the fate of innocents caught in their net.

To understand the gathering of signals intelligence, known as SIGINT, it's easiest to think of a big vacuum. This giant suctioning device enables governments to scoop up billions of bits of information transmitted around the world in cyberspace or on airwaves. Feed that information into sophisticated computers that scan for key words, or read through hundreds of documents and if something jumps out, it lands on the desks of analysts. That intelligence, or chatter as it is sometimes known, is then weighed and either discarded, filed away or immediately becomes part of a larger threat warning.

Immediacy is essential as CSE's U.S. counterparts were reminded on Sept. 12, 2001, when a phone call made two days earlier by a suspected Al Qaeda operative was translated: "Tomorrow is zero hour."

Before his appointment July 1, Adams, like most Canadians, was unaware of CSE's role and admits trying to learn the trade has been like "drinking out of a firehose."

"It's very much a need to know business and so I didn't need to know, so I didn't know," Adams, 63, says.

Traditionally, CSE has been a stealth agency, its leader mute.

The organization's history reaches back to 1941 when Ottawa established a civilian agency to decode enemy telegraphy and radar during World War II. During the late 1940s, a formal information-sharing agreement was signed between CSE, the NSA, (the lead agency with headquarters based in Fort Meade, Md.), Britain's Government Communications Headquarters (GCHQ) and signals intelligence services in Australia and New Zealand.

The agreement's details remain classified but are in play today. Eventually, an agreement, dubbed Echelon, essentially split the world into five geographical areas and each partner country was responsible for eavesdropping on one.

For 34 years, Canada gathered and shared information with its partners mainly under the radar. It wasn't until the CBC profiled their operations on the fifth estate and the ensuing outcry in the House of Commons, that the government admitted its existence.

But little changed as even basic facts such as the agency's budget and staffing numbers were protected for decades. Although, once the Cold War ended, budgets and support dwindled.

"When the wall came down, the Russians became our friends, the Soviet empire went away, and the German frontier withered, all of a sudden, governments are asking what are these guys for?" says Lawrence Surtees, a Toronto telecommunications analyst.

And as they waned, technology boomed. Radar domes, gigantic antennas, and submarines skimming the ocean floor no longer sufficed in the world of fibre optics. As one unnamed source told investigative journalist Seymour Hersh for a 1999 New Yorker magazine piece on signal intelligence: "The dirty little secret is that fibre optics and encryption are kicking Fort Meade in the nuts."

Adams agrees.

"That's why we're so hard at it and why we had to get the increased authorities in order that we could start catching up. The reality is that, yeah, we're behind the eight ball but remember the terrorist is not out there trying to move forward. They're simply exploiting known technologies."

That's where what Matthew Aid, a former NSA operative and author, calls the "boys versus the toys" debate comes in. The technology is keeping pace but what about the experience? At a security conference in Montreal this week, panellists frequently questioned effective analysis — can analysts accurately digest and process the data?

As Adams describes these mathematicians, engineers, linguists and other professionals employed by CSE — the "kids," as he calls them — it's hard not to envision a nerdy frat party raging inside the windowless brick building where they work.

"They can't do what they do anywhere else. They're not allowed," he says. The toys keep them at a relatively low-paying job for their field, offering a challenge is far more alluring than cash.

He says they're among the brightest and most capable in the world.

But is intelligence, however expertly gathered, good intelligence? Had NSA analysts translated the "zero-hour" could they have stopped the attacks?

"As a medium, human communications whether spoken or written is a fickle and unreliable thing," Patrick Radden Keefe, author of the recently acclaimed book Chatter, told the conference yesterday.

The mandate of the CSE - as the code-makers to protect Canadian data and the code-breakers to dissect foreign communication - remained the same after 9/11 but its expanded powers now allow the collection of foreign communication that begins or ends in Canada, as long as the other party is outside the border. A call from Montreal to Islamabad could be monitored, a call from Vancouver to Halifax is off limits.

Adams says the law is strictly followed and the CSE commissioner (who declined to be interviewed for this story) closely monitors their work. But doubts have been raised.

Former CSE employee Mike Frost claims in his 1994 book that during his 19 years working there, the agency eavesdropped on Margaret Trudeau to find out if she smoked marijuana and CSE monitored two of former British prime minister Margaret Thatcher's dissenting cabinet ministers in London on behalf of Britain's secret service.

Adams says the service would never "dignify that with a comment."

David Kahn, who has since 1967 been writing about the CSE's American counterpart, the NSA, says he believes signals intelligence is sticking to the law these days but encouraged strict oversight just to make sure.

"Domestic things they would never do because if it ever came out that the NSA was wiretapping domestic conversations that would be the end of NSA, there would be such an uproar."

Adams stresses repeatedly that Canadians are not being monitored.

"I get very concerned about this Big Brother is watching me. Nothing could be further from the truth," he says. For one thing, the laws prevent it. And, even "with all of your fancy electronic filters" Big Brother couldn't keep up. "Big Brother would just be overwhelmed."