Internal Affairs, Microsoft team on technology to censor internet photos

InternetNZ policy lead Susan Chalmers

Investigators tackling the trading of child sexual abuse photos on the Internet will now find it easier to detect objectionable images, Internal Affairs Minister Amy Adams says.

The Department of Internal Affairs’ Censorship Compliance Unit has been working with Microsoft on the development of PhotoDNA, which it describes as a world-class technology designed to identify and remove images that exploit or endanger children.

The project has echoes of the department's Digital Child Exploitation Filtering System, rolled out in partnership (on a voluntary basis) with major ISPs in 2010 - which some saw as the thin end of the wedge.

Then InternetNZ policy director Jordan Carter told NBR that although child pornography was “abhorrent," enforcing filtering systems onto internet service providers would not stop the problem, and could lead New Zealand down a "slippery slope" of increasing censorship, and potential abuse of state power.

Tech Liberty campaigner Thomas Beagle said the programme was a breach of (then) ICT Minister Steven Joyce's promise, made in NBR on March 13, 2009, not to instigate any filtering programme - a reaction to the Australian government’s filtering trial under which not just nefarious sites but mainstream adult sites, gay sites, and even a dentist’s site were (often inadvertently) blocked.

Tech Liberty: potentially useful tool
Mr Beagle was more relaxed about the Microsoft co-developed technology announced today, will allow investigators to detect and process objectionable images more efficiently as well as re-examine the methods they use to review the images.

"It looks like a useful tool to enable the CCU [DIA Censorship Compliance Unit] to review seized images more quickly," Mr Beagle told NBR.

From initial information, it seemed there was no intention of trying to insert such software as part of the DIA's internet filter, said the Tech Liberty advocate and Council for Civil Liberties exec.

"We think it is important that any such tools are only used to help investigators and that in all cases the final decision should be made by a person. We don't need more Scunthorpe problems where innocent photos are tagged as indecent due to over zealous software."

InternetNZ: need checks and balances
InternetNZ Policy Lead Susan Chalmers told NBR, "InternetNZ fully supports the efforts of the DIA in fighting the trading of child sexual abuse images online. We therefore welcome the use of PhotoDNA to assist the DIA in its important work in this area. 

"We should always keep in mind, however, that as these types of technologies advance, there must be checks and balances for how they are used by governments. Internet users should be assured that PhotoDNA is used by the government only for its stated purpose - to combat the trading of child sexual abuse images and to help the victims of such abuse."

Tuanz: somewhat wary
Telecommunications Users Association chief executive Paul Brislen also gave a cautious thumbs up.

"I'm somewhat wary of automating the awful process of identifying objectionable material to any degree," the Tuanz boss told NBR.

"Software isn't infallible and false positives are a major concern for all involved," Mr Brislen said.

"However, giving the DIA the tools they need to manage the process is important so long as it doesn't replace the human decision making that will spot the difference between objectionable material and someone's holiday photos."

A first
Ms Adams said New Zealand was one of the first countries to deploy such technology.

“The trading of objectionable images of children is abhorrent to me and most New Zealanders, and as a government we will be doing what we can to stop it,” Ms Adams says.

“This gives investigators another valuable tool to help us in the fight against this problem.

“Millions of objectionable images are circulating the internet and PhotoDNA could help rescue the victims of abuse and find the offenders.

“During the forensic analysis of a seized computer system, it is common for the Censorship Compliance Unit to review more than 100,000 image files. This technology will make the process much faster.

“It will also allow a greater level of information sharing with our international partners as more systems come online that use this technology.”

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7 Comments & Questions

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Our govt is no better than China

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I would imagine that the first country in the world to use DDT also thought that they were pretty cool too.

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you two are both idiots

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Let the tracking begin

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Great idea, but this is doomed to fail. The overwhelming majority of internet traffic containing such images is done over end-to-end encrypted connections. Unless Microsoft or ISP's have some magic way of decrypting traffic on the fly, this is only ever going to block a very tiny minority of images.

Furthermore, a further flaw is that this is only ever going to catch novices or those dabbling in this extreme side of porn. This is like catching drug users and throwing them in jail, rather than catching those producing or dealing said drugs.

What a waste of time and effort. I would rather see the resource being spent on rescuing kids from those thugs beating their children to death in this country, rather than mucking about with this nonsense, especially since it will hardly make a single difference.

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the dealers will just change their ways of operating. Nothing will change by addressing the 'supply' side without reducing 'demand'.

This approach is a waste of time and money

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There is more info on the official website: <url></url>.

As explained there:

"PhotoDNA is an image-matching technology developed by Microsoft Research in collaboration with Dartmouth College. It creates a unique signature for a digital image, something like a fingerprint, which can be compared with the signatures of other images to find copies of that image."

"The weakness in most common forms of hashing technology is that once a digital image has been altered in any way - whether by resizing, resaving in a different format or through digital editing - its original hash value is replaced by a new hash. The image may look exactly the same to a viewer, but there is no way to match one photo to another through their hashes. The PhotoDNA technology extends the signature to make it robust and reliable, so that even if you change the image a little bit, we can still find it."

And, in relation to false positives:

"To date, we have evaluated more than two billion images on our services using the PhotoDNA signatures provided by NCMEC, leading to the identification of more than 1,000 matches on SkyDrive and 1,500 matches through Bing's image search indexing. A rate of zero false positives shows that the combination of technology and partnership with NCMEC delivers a powerful ability for responsible online service providers to surgically identify and disrupt the spread of known child pornography online."

PhotoDNA is available at no charge to law enforcement agencies.

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