Fundamental to the proper functioning and defense of the SIM card, the PIN and PUK are two numeric codes
Probably, even though we use it very often, we don't "know" exactly what it's for. We don't know much about its "twin brother" since we use it even less frequently. Yet, PIN and PUK are an integral part of how a SIM works and, as a result, of our experience of using a cell phone.
And if the PIN is more known and used, the PUK remains for many an "obscure object" despite being of fundamental importance for the security of our phone number. For this reason, it is essential to know what PIN and PUK are and what they are used for: only by knowing them, in fact, you can use them at their best and avoid nasty surprises when you have to recover them.
What is the SIM PIN code
Acronym for Personal Identification Number (Numero di identificazione personale in italiano), in general the PIN is a string of numbers of varying length that is used to verify the identity of a person who wants to access a particular service. When we talk about the SIM PIN we are referring to a four-digit code created randomly by the phone operator and imprinted directly on the card that also contains the cell phone card. The PIN is used to unlock the SIM and access its contents and features. As you can easily understand, the PIN is used to defend the SIM and prevent anyone from unlocking it, thus having free access to our phone number and the information stored on the same phone card (such as contacts and SMS, for example=.
SIM PUK code
Acronym for Personal Unblocking Key, the PUK is a string of eight digits randomly created by the mobile operator and imprinted on the plastic card that contains the SIM card itself. The PUK is a secondary security code that allows you to unlock the SIM in case you forget your PIN. In fact, if you enter the wrong PIN three times in a row, the cell phone card will be locked for security reasons: to return to use it you will be asked to enter the PUK. If you enter the wrong PUK 10 times, the SIM card will be locked forever and therefore unusable.