I don’t understand this

A number of web companies are teaming up to create a database of child porn images, which they claim will be used to monitor for child porn being distributed around their networks, in much the same way antivirus companies keep virus databases, and antispam companies keep corpuses.

I’m afraid the analogy falls down for me there. Anyone that’s ever worked with digital images knows that as soon as you resize the image, the file becomes completely different. The filesize changes, the datastamp changes, and the content of the file changes. Sure, there are algos for comparing images based on how they “look”, but aren’t these very hit and miss?

I’d be interested in the opinions of digital artists and graphic designers, because as far as I can see this looks like an initiative created to make it look like something is being done, instead of actually doing something.

Plus of course the global move to broadband and the massive growth of P2P creates other questions, such as: Who looks at porn jpegs anymore, for chrissake? JPEG is sooo nineteen nineties!

(I’m being facetious, perhaps these scumbags are restricted to JPEG because of difficulties with distribution. Still, it seems unlikely.)

4 Responses

  1. There are a few different methods of comparing images – one of the more simple ways graphs the RGB make-up of the image, represents it as a curve. A resized image will still be flagged as similar to its original. There are ways to fool any such algorithm, but for the most part, it works. Projects like this have been going on for a long time – not least in UCC, and the analytical algorithms are fairly advanced.

    Its not a silver bullet, but if they have many of the common photographs that are doing the rounds, then it will help to an extent at least.

    Good point about the jpg’s – but there are similar means of comparing video files (e.g., splitting the movie into keyframes and analysing each of these as images).

    Using this kind of technology, theoretically I think child porn on the internet could be almost eliminated, e.g. if every major ISP mirrored and updated a central database, but in the process it might infringe too much on civil liberties.

  2. The UCC project has been shut down and I think they moved it to Spain. It was funded by Interpol. Adam, the thing is I’m sure a lot of these photos will never be changed or renamed and so they’ll be able to catch a lot more people than they do now. The more devious of these nasty people will I’m sure use more intelligent methods of evading the authorities and hopefully there’ll be other methods to catch these people.

  3. Fair points, both of you. I understand better, and I\’m less skeptical. Less sceptical. :) (I used both spellings cos I\’m never sure which is right!)

  4. I suppose any clever person distributing child porn would zip/rar the images, and rename to .mp3 or something.