BlueToad, a digital publishing company in Florida, said a stolen list of 1 million Apple device IDs came from its computers, not the FBI's as an Internet hacker group has claimed.
The company's CEO and president, Paul DeHart, said BlueToad took a look at the stolen data that had been posted online, compared it with the company's data and found that there was a "significant match."
"At that point we knew conclusively that it was our data that'd been compromised," he said in a phone interview, adding that the company was the victim of a cyber attack a week and a half ago.
DeHart said BlueToad develops apps for magazine, newspaper and book publishers.
"For now we'd like to avoid disclosing any of our clients," he said. "We want to avoid any unnecessary reaction."
The data was posted online last week by AntiSec, a hacker group associated with Anonymous. The group said it hacked an FBI official's laptop for the data, which the federal agency denied.