If your iPhone or Android smartphone PIN starts with 1234, 0000, 2580, 123456 or 654321, you are in a soup as these PINs are most prone to hacking as your device can be unlocked easily by others.
According to the study, the 10 most popular four-digit PINs are: 1234, 0000, 2580, 1111, 5555, 5683, 0852, 2222, 1212, 1998. The most popular six-digit PINs are and 123456, 654321, 111111, 000000, 123123, 666666, 121212, 112233, 789456,159753.
Researchers at Ruhr University in Germany showed that the blacklist used by Apple to prevent particularly frequent PINs could be optimised and that it would make even greater sense to implement one on Android devices. It emerged that six-digit PINs do not provide more security than four-digit ones.
“Mathematically speaking, there is a huge difference, of course. A four-digit PIN can be used to create 10,000 different combinations, while a six-digit PIN can be used to create one million,” said study researcher Philipp Markert from Horst Gortz Institute for IT Security in Ruhr University.
“However, users prefer certain combinations; some PINs are used more frequently, for example, 123456 and 654321, this means users do not take advantage of the full potential of the six-digit code,” Markert added.
The research has shown that the ideal blacklist for four-digit PINs would have to contain about 1,000 entries and differ slightly from the list currently used by Apple.