Apple's fingerprint scanner is a security nightmare waiting to happen, according to a German expert.
One of the few new technologies installed in the new iPhone 5S was fingerprint scanner which was designed to make the phone less likely to be nicked. After all a phone thief would never be able to mimic your fingerprints unless they were taken in the theft.
Like most of Apple's recent "killer apps", such as half-baked ideas like Apple Maps and Siri, the technology has shipped broken.
Der Spiegel has reported how Hamburg data protection Johannes Caspar is warning people not to go near the technology.
His fear is that the biometric features of your body, like your fingerprints, cannot be erased or deleted. They stay with you until the end of your life and stay constant, they cannot be changed.
If you stick this information onto any electronic device, and it is hacked, then the hackers have something that you can never change.
Caspar finds Apple's argument that 'your fingerprint is only stored on the iPhone, never transmitted over the network' weak and misleading.
He said that the average iPhone user is not capable of checking, on a technical level, what happens to his or her fingerprint once it is on the iPhone.
Apple fanboys cannot tell with any certainty or ease what kind of private data applications downloaded onto the iPhone can or cannot access.
The recent disclosure of spying programs like Prism makes it riskier than ever before to share important personal data with electronic devices, he warned.
Caspar said that, as a matter of principle, one should never hand over any biometric data when it isn't strictly needed.
He said the problem with Apple's arrangements is that the user's fingerprints are stored on a file on the phone. Apple has shown in the past that it can't control apps on the phone, and cannot have any control over the fingerprint file.
Caspar said that even before the discovery of the NSA's Prism programme it was not without risk to trust technical arrangements for this sort of data. Apple's fingerprint technology gives spies and hackers a holy grail to search for.