personal unblocking key (mobile communications) (PUK)

In addition to the personal identification number ( PIN ), the personal unblocking key (PUK) is another protection mechanism for the unauthorized use of devices and systems with security mechanisms.

The PUK key is known from cell phones and electronic ID cards, among other things. If, for example, the personal identification number (PIN) is entered incorrectly several times in a cell phone, an error operation counter registers the incorrect entries and blocks further entries of the personal identification number (PIN) after a preset number of incorrect entries. The block can only be removed by entering the PIN Unblocking Key (PUK), also known as the Super PIN, and entering a new PIN number.

The PUK number is a multi- digit sequence of numbers. If it is entered incorrectly several times, it is blocked. In this case, a new SIM card must be requested from the network operator or an activation must be applied for.