Activation is basically a process by which a new or recently restored iPhone can get by the “Emergency Call Screen” and it also enables your iPhone to connect to a cellular network.
The code or “ticket” that allows activation resides in the iOS lockdownd folder.
When you connect your iPhone after a full restore, iTunes generates an Activation Token and sends it to Apple’s activation server. Once the Activation Token is validated, the server will generate a WildcardTicket and signs it with Apple’s private key.
The WildcardTicket is then used for activating your iPhone’s baseband. It is stored in the file “/var/root/Library/Lockdown/activation_records/wildcard_record.plist”. It has all the information about SIM or network unlocks. Factory-unlocked iPhones receive a WildcardTicket that permits any SIM card.
Apple’s “Albert” servers handle all iDevice related activations which was recently patched by Apple to discontinue any “fake” activations via loktar_sun’s SAM unlock method.
The iPhone needs a cellular data connection for the first time, after the activation in iTunes. You can make calls if an alert says “iPhone is activated”.
Each ticket is unique to each SIM card and iPhone so this is the reason why you’re not able to use your saved activation ticket on multiple devices.
I hope that wasn’t too technical… but that’s basically how your iPhone gets unlocked. This ticket is valid for 3 years so it’s vital that you save it in case you need to do a full restore on your iPhone.
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via iPhonewiki and image courtesy 365daysofdesign.org
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