When questioned about what his job entails, Roger Sutton pauses for a minute, slowly deliberating about what he's permitted to reveal.
"Let's just say at certain times there have been elements of danger in my job," he responds, carefully.
His furtiveness is understandable. The 64-year-old Brit has made his livelihood from keeping classified information under wraps and, for the past 24 years, he has worked for Crypto AG, a Swiss firm specialising in communications security.
When industries, governments, secret services and militaries want to transmit sensitive information in strict privacy, Sutton's the man they turn to. His firm makes sure emails, faxes, phone calls and radio signals are completely secure.
Nevertheless, when pressed, Sutton, who's been based in Crypto's Abu Dhabi office for the past decade, is prepared to impart certain anecdotes from his career, albeit in scant detail.
"One of my scariest moments was in Kuwait City in 1990 when Iraq invaded, but I managed to get out just at the last minute. This was fortunate, as let's just say the reason I was there was not unrelated to the invasion," he recalls.
"And I've been dropped by helicopter in the jungle right in the middle of a combat zone, where we were fired at by rebel armies."
However, Sutton is at pains to point out he's not some kind of heroic super-spy.
"No, I'm not a secret agent by any means. I'm an engineer by training, so I'd say I was more of a Q-type figure than James Bond. It's more technical stuff than actual espionage work," he admits.
"But I've been doing this so long I've got lots of lovely stories that I could divulge, but obviously I can't. My best advice would be to read my book, as this, and a sequel I've planned, will be the closest you'd get to hearing some of my career stories.
"There's plenty [of truth] in there. Obviously I can't specify what and, of course, because it's fiction, I have embellished some of it."
The book is A Need to Know, Sutton's debut, self-published novel. With a plot involving a succession of brutal murders, a terrorist assault on a US aircraft carrier and, perhaps most implausibly, a helicopter smashing into the Burj Al Arab, he's clearly not averse to enriching his yarn with some far-fetched storytelling.
Witness to all the this carnage is our hero, Mike Ashley, a journalist for Jane's Defence Weekly, the famous military magazine, whose "tough childhood environment amongst the steel mills of South Yorkshire had instilled a healthy dose of resourcefulness and tenacity".
Haunted by the death of his beautiful Indonesian bride in a terrorist attack, he's commissioned by the British secret service to track down a leading cryptologist who vanished just before he's meant to deliver a keynote speech at a military conference in Toronto.
Ashley jets off to the Canadian city to find the missing expert but, in a familiar-sounding plot device, he cracks a secret code hidden in a crossword clue that portends a terrorist attack in the Gulf. Hence, the action swiftly moves to Dubai's luxurious hotels, lush golf courses and seedy nightspots.
However, those with a knowledge of football's English Premier League might question why Sutton's named his central character after Newcastle United's controversy-courting, billionaire chairman.
Sutton says: "When I wrote this book in 2006, Newcastle's Mike Ashley wasn't so well known, and so I thought nothing of naming him Mike. In fact, I wanted to call him Rick, but my daughter said he might be confused with the singer Rick Astley. That was a shame, because I liked the name Rick, it kind of created a face in my mind."
Sutton is keen to distance himself from suggestions that Mike might actually be Roger, despite the fact that both he and his protagonist count Sheffield as their hometown.
"We're both from the same city, yes, but that's where the similarities end," he explains.