June 16, 2011 -- Of the 10,000 different number combinations you can choose to lock your iPhone, a surprising number of people use one of five common pass codes, one developer revealed.
Through his own security app, Daniel Amitay found that nearly one in 10 of the numerical pass codes users choose to lock their phones are one of five common four-digit combinations.
Those five: 1234, 0000, 2580 (which make up the center column of numbers on a phone's keypad), 1111, and 5555. Number six on the list, 5683, is the least obvious—until you realize it spells "Love" on a keypad.
The rest of the top ten were also somewhat guessable: 0852 (going back up the center column), 2222, 1212, and 1998.
Amitay, a 20-year-old economics student at New York University, looked at 204,508 pass codes recorded by his application, Big Brother Camera Security.
His app replaces the built-in lock screen with a fake lock screen. If an incorrect code is entered into the fake lock screen, the camera takes a picture of who entered the code and e-mails it and the GPS position of the phone to the owner.
That app also sent back the user's pass code to Amitay's servers anonymously—so he could gather the information on which codes were being used too often.
Of the 10,000 possible combinations, Amitay noted that 30 weren't used at all. He said the average passcode was used about 20 times, but half were only used 10 or 11 times.
To be clear—Amitay's app didn't send official pass codes back, but the codes people used to lock their phones with his application.
Apple has disabled Amitay's app and it is no longer available in the app store. Amitay said he received a phone call from Apple's Developer Relations department, who told him his app was disabled for "surreptitiously harvesting user pass codes."