What is a PIN?
A PIN is a short numeric code protecting a card, phone, or device. Four digits allow only 10,000 combinations, so most of a PIN's security comes from the attempt limit and from avoiding the small set of numbers that many other people choose.
- Topic
- Authentication
- Also called
- personal identification number
- Reading time
- 1 min
- Reviewed
On this page
Why human PIN choice is the weak point
Analysis of 3.4 million exposed four-digit PINs found that 1234 alone accounted for over 10% of them, and the ten most common covered roughly 20%. A further large cluster follows the MMDD shape of a date or sits in the 19xx range of birth years. A thief with three attempts and a guess list does far better than 3 in 10,000.
Six digits where you can
Moving from four digits to six multiplies the space by 100, from 10,000 to 1,000,000 combinations. Phones and banking apps generally allow it. Cards often do not, in which case randomness matters even more.
Sources
These primary references support the terminology and current security guidance used in this definition.
