This is an error message thrown up by iTunes when someone attempts to carry out an iOS upgrade on an iPhone 6/6 Plus/6s/6s Plus (the iPhone 5s is not affected). It affects handsets that have had the Touch ID sensor or the ribbon cable that connects to the mainboard replaced by a third-party repairer, or has been damaged or tampered with in some way.
Reports from iPhone owners affected by this issue suggest that upgrading from iOS versions 8.1 and above can trigger this error.
It is permanently disabled, otherwise known as 'bricked.'
The only known fix is to refit the original Touch ID sensor and cable.
Have repairs that relate to the Touch ID system carried out by an Apple authorized repair center. Bear in mind that screen damage might cause secondary damage to the Touch ID system.
While the iPhone 5s does have a Touch ID sensor, it does not have support for Apple pay, so presumably this error relates to that, but this is all speculation.
The coverage might be new, but research suggests that this dates back to the release of the iPhone 6/6s.
Apple sent the following to ZDNet last week:
"We take customer security very seriously and Error 53 is the result of security checks designed to protect our customers. iOS checks that the Touch ID sensor in your iPhone or iPad correctly matches your device's other components. If iOS finds a mismatch, the check fails and Touch ID, including for Apple Pay use, is disabled. This security measure is necessary to protect your device and prevent a fraudulent Touch ID sensor from being used. If a customer encounters Error 53, we encourage them to contact Apple Support."
If your handset is under warranty and there are no signs of damage then it seems that Apple will exchange it. If it is outside of warranty, the warranty has been voided, or Apple suspects that the handset has been tampered with in some way, then the only recourse seems to be to buy a new iPhone.
I'm having a hard time imagining a situation where Tim Cook and the gang would gather in a conference room at Apple HQ to conjure up a plan to brick handsets. Leaving customers disgruntled and creating a media furor is not a good way to generate sales.
On the other hand, we have a situation where Apple is releasing code that does disable handsets, and is issuing tone-deaf press statements that justifies this under the banner of "security."
That would be something for the courts to decide, however, The Guardian is reporting that one UK barrister believes that " it was likely that Apple's actions breached basic consumer laws in the UK, and added that it could be committing an offence under the Criminal Damage Act 1971."
Specifically, the law in question states:
"A person who without lawful excuse destroys or damages any property belonging to another intending to destroy or damage any such property or being reckless as to whether any such property would be destroyed or damaged shall be guilty of an offence."
Glad you asked!
What we have here are the inevitable teething troubles of baking strong cryptography into consumer devices. Consumers want the peace of mind that comes from strong security safeguarding their data and money, but they want the freedom and convenience of being able to meddle with their devices.
Side note: The same is true in the automotive industry. People want their cars to be safe, but also want the ability to have new keys reprogrammed, or have the radio replaced without paying dealer prices. It's now trivially simple to reprogram new keys or even take the radio from one car and fit it into another for most makes - all you need is the right scan tool.
Also, this isn't the first time that we've seen devices being bricked because of hardware security. There are plenty of examples where TPM (Trusted Platform Module) issues bricked PCs.
You can't have both, but I think that a better balance can be struck. Bricking people's iPhones in the name of security is heavy-handed and draconian. If Apple believes that messing with the Touch ID sensor weakens security, then I would suggest that warning the owner and disabling the sensor would suffice.
I would expect that Apple is working on this issue and that over the coming weeks we'll see a change in the way iOS updates handle tampering with the Touch ID system. In the meantime, if you've had your Touch ID sensor changed or messed with, don't update iOS. Better to be on an old version than be left with a bricked handset!