How important is privacy to you? Are gigantic corporations ever justified
in snooping around our own personal files? These are the thorny questions
currently being debated as Apple announces the rollout of a controversial – some would say
dystopian – raft of souped-up privacy measures on its upcoming iOS update.
How worried should you be? To what extent is AI about to become an all-powerful arbiter of
what’s right and wrong? Can, or should, anything be done to reverse this trend?
Join us today as we peel back the veil and ask why Apple is secretly scanning your photos.
Apple loves to paint itself as the one big tech brand that actually cares about your privacy.
Unlike, say, Google or Facebook, whose entire business model relies on siphoning
your precious data to make a fast buck, Apple stans are instead encouraged to
feel smug about how their data is never used to inspire a never-ending cascade of spam.
Which is why Apple’s latest announcement has caused several
self-styled champions of liberty to speak out.
So what’s the new announcement all about?
As part of an industry-wide effort to wipe out abusive and illegal practices online,
Apple’s forthcoming iOS update will allow the company to compare private images stored on
iPhones, iPads and Macs with a visual database of known Child Abuse Materials, also known as CSAM.
The idea is to identify active child abusers, who’ve long exploited the internet’s potential
for anonymity as a means of disseminating their horrific and abusive materials.
If a match between an iPhone photo and a known image of abuse is made,
that users’ account will be suspended and referred to law enforcement.
Most people probably have no issue identifying dangerous active child
molesters and referring them to the proper authorities.
However, the real question is: by which mechanism are they identified,
and is that system itself ripe for abuse?
Here’s Apple’s explanation, straight from the horse’s mouth.
‘Before an image is stored in iCloud Photos,’ reads the company’s statement, ‘an on-device
matching process is performed for that image against the unreadable set of known CSAM hashes.
‘This matching process is powered by a cryptographic technology called private set
intersection, which determines if there is a match without revealing the result.’
‘Private set intersection (PSI) allows Apple to learn if an image hash matches
the known CSAM image hashes, without learning anything about image hashes that do not match.
‘PSI also prevents the user from learning whether there was a match.’
Hashing, in this case, refers to the cryptographic practice of codifying images into unique number
strings. This is the same technology used by YouTube to automatically spot music piracy, by the
way, so it’s nothing new. Apple are calling their latest refinement to hashing tech ’NeuralHash’.
NeuralHash, in theory at least, can not only match photos with an established database of
CSAM images, but also automatically spot any sneaky workarounds used by abusers
to try and cheat the system. For instance if bad actors crop,
rotate or otherwise manipulate the offending images in order to escape detection.
If a match is made, another cryptographic principle called ‘threshold secret sharing’
comes into play. Which means that if a certain – undisclosed – number
of matches are flagged up by NeuralHash’s automatic process,
the images can then be decrypted and potentially escalated to a manual human checker.
So to recap. An official, state-sanctioned database of known abusive images is encrypted
onto a hashing database. The photos on your iPhone are similarly encrypted,
and their hashes compared with that database in order to identify a match. This all
happens automatically, by the way, with no human intervention, at this stage anyway.
If a given number of those hashes matches up,
the offending photos are flagged as potentially abusive, and only then sent on for verification.
Hashing algorithms are by no means foolproof – the YouTube music piracy algorithm,
for instance, regularly throws up false positives. But it certainly isn’t fair
to say that Apple – or anybody else – is ‘spying’ unbidden in your private snaps.
According to Apple the chance of a false positive emerging after all
the proper steps has been followed – this system was designed in collaboration with
eminent Stanford University cryptographer Dan Boneh – is around one in a trillion.
Genuine matches, where there is a legitimate cause for concern,
are escalated to the National Centre for Missing and Exploited Children, an entity that acts as a
central repository for CSAM investigations and works closely with law enforcement.
At first the rollout will only take place in the US, at some point in the coming months.
Apple is at pains to point out the new process will only be applied to images
stored in iCloud photos, and not those stored locally on devices. The thinking here is that
while you might own the phone, you certainly don’t own the cloud, so different rules apply.
In addition to this measure, Apple is also introducing new safety features aimed at
helping minors who use iMessage stay safe from online predators, by swiftly identifying
potentially explicit images as they’re being exchanged, then flagging them up to parents.
‘Protecting children is an important responsibility,’ says the company in a statement.
Certainly these measures have been welcomed
by in-the-know figures in the world of child safeguarding.
John Clark, President & CEO at the National Center for Missing & Exploited Children,
called Apple’s new protections ‘a game changer’,
adding ‘the reality is that privacy and child protection can co-exists.
‘We applaud Apple, Apple and look forward
to working together to make this world a safer place for children.’
Bigwigs in the world of cryptography are similarly
impressed. David Forsyth – Chair in Computer Science in the University of
Illinois at Urbana-Champagne College of Engineering – had this to say.
‘Apple’s approach preserves privacy better than any other I am aware of.
‘In my judgement this system will likely significantly increase the
likelihood that people who own or traffic in [CSAM] are found.
‘Harmless users should experience minimal to no loss of privacy,
because visual derivatives are revealed only if there are enough matches to CSAM pictures,
and only for the images that match known CSAM pictures.’
However, several concerned citizens online have pointed out this measure is a classic
slippery slope. As it’s technically a government agency, and not Apple,
determining what images are legit and which aren’t, the potential for malpractice is obvious.
We can all agree kids need protecting, but what if this infrastructure is used
by bad actors in future to identify, say, political dissent? Or meetings
with friends or family that the state – or any foreign state – deems to be a threat.
Clearly it’s the government that has the whip hand in these issues. Last year,
Apple proposed to encrypt users’ full phone backups to iCloud,
but the FBI stepped in claiming it would harm investigations into child abusers and other
nefarious activities. Many would argue the ends justify the means. Or do they?
Again, we ask the question – how important is privacy to you?