Security researchers Nick DePetrillo and Don Bailey have discovered a seven-digit numerical code that can unlock all kinds of secrets about you.

It’s your phone number.

Using relatively simple techniques, this duo can use your cell phone number to figure out your name, where you live and work, where you travel and when you sleep. They could even listen to your voice messages and personal phone calls — if they wanted to.

“It’s really interesting to watch a phone number turn into a person’s life,” DePetrillo said.

“Everyone’s taught to keep their Social Security number a secret,” Bailey said. “But the phone number seems just as dangerous, if not more so.”

The world has come a long way from old-style telephones, which were little more than a speaker, a bell and a microphone. But as smart phones become more powerful and widely used, they also become busy hubs for data, packed with a user’s digital Rolodex, e-mails and credit card details. Most phones are also fitted with a global positioning device that beams its location far and wide.

DePetrillo and Bailey are part of a busy community of security researchers investigating and exposing the many security holes that have yet to be plugged by smart-phone makers and their wireless carriers.

Once they have a phone number — yours, for instance — they can easily determine your name by taking advantage of a vulnerability in the Caller ID system. Using special software, they can “spoof” a call — that is, make a call that appears to the phone company as though it’s coming from your number. They can then call themselves using your number and watch as their Caller ID device lights up with your name.

But it doesn’t stop there: Once DePetrillo and Bailey have figured out your name is the one associated with your number, they can query the cellular network to see where your phone is at that moment. After enough time, this bit of digital spycraft will yield a fairly clear picture of where you go.

Used by about 21 percent of mobile phone customers, smart phones like iPhones, Androids and BlackBerrys are quickly gaining ground on the previous generation of simpler flip phones, and by 2011 they are likely to become the standard for most consumers, according to Nielsen Co.