Worse, the way that the system is designed, you only have ten chances to enter the correct PUK and then the SIM will lock down and be unusable, even in the original phone. Here’s what SIM cards look like, in case you’re not sure:īack to the PUK: they’re basically the “secret unlock key” for your SIM card and 99% of the time you’ll never even know it exists and is tied to your SIM card because your phone should never prompt you for the PUK. Your phone calls, your text messages, all would automatically route to the new phone because the cellular network itself has no way of confirming that the bad guy’s phone isn’t the real thing. Problem is, leave your phone alone for two minutes and someone with sufficient knowledge can easily pop the SIM card out and slip it into their own phone, even one that’s quite a different brand, and then masquerade as you on the cellular network. Without a SIM card your phone doesn’t exist on the cellular network and with it, your phone’s “identity” is known whether you’re in Kuala Lumpur or Miami Beach.

What’s a SIM card? I knew you’d ask that! A SIM card is a subscriber identity module and it’s the tiny little plastic card buried deep in your cellphone, whether a super smart Galaxy S7 or iPhone 7 or a simpler phone like an LG Xpression.

A PUK code is a personal unlocking key and it’s tied to your SIM card.

At&t unlock code