The best Subscriber Identity Module (SIM) Personal Identification Number (PIN) should be easy to remember, but hard for someone else to guess. There are a number of tricks people can use when picking PINs and passwords to allow themselves to create secret codes that will meet these requirements. With PINs, this can be more challenging because the code is not alphanumeric, making it impossible to mix letters, numbers, and punctuation to make the number hard to guess.
Commonly, a SIM PIN is four numbers long. Subscribers may need it to unlock a phone so they can make system changes, and if the code is not correct, the phone will automatically lock after three tries. This is designed to protect people from unauthorized use of their phones and private information. When they insert a SIM card into a different phone, the same SIM PIN will be used to unlock it and make the new phone usable.
It is a good idea to avoid identifying information in a SIM PIN. People shouldn’t use their birth dates, parts of government identification numbers, addresses, and phone numbers, for example. It is also a good idea to avoid similarly identifying information associated with close friends and family; a child’s birthday, for example, is not a very secure SIM PIN. In case of hacking or cracking, people should also avoid any number they have used as a PIN in the last year.
Making a SIM PIN harder for someone else to guess can involve creating a code of personal significance that another person wouldn’t think of. A historian who studies the Battle of Hastings wouldn’t want to choose 1066, the year of this famous historical event, for example, but might choose 1729, the date when the Bayeux Tapestry commemorating the battle was rediscovered by researchers. In addition to dates, people can choose number strings like page numbers associated with favorite quotes or time marks on a video.
Another option is to use a random number generator for a SIM PIN. This will generate a number that is unlikely to be guessed by another person unless it coincidentally creates a string like 1234 or the subscriber’s birthday, in which case the program can be run again for a new set of numbers. Random number strings like this can also be used to encode longer passwords by distributing the numbers into an alphanumeric pattern known only to the individual subscriber. For example, a person could use the code 7205 in a string with a word associated with a website and two pieces of punctuation, like !7kno2;wled05ge for an education website or wiki.