04 June 2012

Cyberspace June 2012

I like gadgets and travelling, so Hong Kong is a great place to go. Recently at the Stanley Markets I was offered a pen that could record video and sound. Fortunately for me I wasn’t interested, because the Surveillance Devices Act 2007 has something to say about it. You can purchase wireless network cameras for around $200 that record audio and video. You can buy cuddly toys complete with webcam, and of course you can buy baby monitors. You can even buy a video recorder with 8GB of memory that is built into a very convincing stainless steel watch, as well as a shelf clock that has motion detection that videos in high definition. And if you can’t make it to Hong Kong you can buy the pen spy camera with 8GB of memory online for $80.

The Act deals with things that were once very much in the realm of surveillance professionals, but now are cheap, moderate quality and easy to purchase. The devices covered by the Act include optical, data, listening and tracking devices. Unless you have a warrant you just can’t do some things when the subjects intend their actions to be private, and it’s illegal to manufacture, supply or possess such devices with the intent of contravening the Act. Unless you plan to film your child’s soccer game holding a pen, I’m not sure what the spy pen camera is for...

People want to conduct surveillance for many reasons - preventing theft is common, but estranged spouses might look for ammunition for their cases, and some people are just nosey. Of course, illegal data surveillance, which is the monitoring of input or output of computer information or a network without consent is a favourite activity in the online world. Section 10 prohibits it, and like the other offences is indictable.

So, what about the James Bond pen? Using a listening device to overhear, record, monitor or listen to a private conversation to which the person is not a party is prohibited by s.7. Fortunately the conversations usually relayed by a baby monitor are more along the lines of “you need to change me”. More usefully, these sorts of devices were used in some of the houses used by the recently arrested Malcolm Naden to alert police as to his presence. Heat-sensitive devices were also used, but they aren’t covered by this Act.

Optical surveillance devices are any device capable of being used to record visually or observe an activity, and using them is prohibited by s.8 if unauthorised entry or interference with a vehicle is required to use or maintain them. So that doesn’t stop you having a video intercom at your front door, but it certainly will stop someone bugging their ex’s house.

Tracking devices are reasonably popular with parents who want to check on their children, but section 9 says that you must not install, use or maintain a tracking device to determine the geographical location of a person or object without express or implied consent by person or person in possession of the object. This rules out the tracking device up Arnold Schwarzenegger’s nose in the film Total Recall, and it also rules out attaching a GPS to someone’s car.

So, while you can visit ThinkGeek (http://www.thinkgeek.com) and buy the Rear View Spy Sunglasses,  Midnight Shot NV-1 Night Vision Camera and the Laser Trip Wire, you probably shouldn’t get the SpyNet Night Vision Video Watch.

On a final note, don’t forget that the Workplace Surveillance Act 2005 has something to say about these sorts of activities too.

First published in the Journal of the Law Society of New South Wales, June 2012. © 2012 Andrew Calvin, Sydney, Australia

Cyberspace May 2012

Lies, damned lies

In 2050 no grandchild will see a photo of his grandfather sitting on his antique motorcycle, because that photo was taken on a phone or digital camera and was never backed up or handed over to the children (“Here honey, take my 30 GB of family photos before I die”).. Another problem with digital photographs is that they are easily edited... but are those edits undetectable?

You might be involved in an AVO defence, a claim against police or a family law matter where some photographs are being tendered. What can you do to ensure that they haven’t been tampered with? I’d start by cross-examining on the chain of custody of the digital images, starting with the photographer and ending with the person tendering them in court.  The concept of an “original” photograph is fairly nebulous - perhaps the only original is that on the SD or Compact Flash card - everything else is suspect. But the truth is that you can analyse a photo that has been resized, cropped, altered and find the fakes.

There are many techniques (and multiple techniques should always be used) but only some deal with visible issues. Classic visible problems are where the light appears to illuminate a subject from several directions when there clearly could only have been one light source. This analysis can show that one or more subjects have been added, moved or reversed. Another visible problem is where perspective anomalies arise.  If an object is inexpertly added then its perspective will not match the rest of the photograph. This can show, for example, that the wheels on a car are too close together or people are too far away from a background object. Changes in highlights (bright areas) where you would expect them to be similar was noted in a Scientific American article (http://goo.gl/Og0Tv), where a photograph of American Idol judges was analysed to show it had been doctored.

But what about edits that are seriously professionally done using quality software? These are still detectable.  A great recent example was by Dr Neal Krawetz, who has been conducting digital photo forensics for many years. In the USA a recent lottery draw for over $640M was world news. A person posted three photographs of a “winning ticket” on Reddit, and Dr Krawetz decided to examine them (http://goo.gl/qhcjS). . These photographs were seriously believable visually, but the context indicated they were probably fake, and he ultimately proved so. How?

The first picture was analysed to see if different areas of the image had been compressed at significantly different levels (all JPEG photos have some degree of compression). Even after multiple saves we should see consistent degradation across an entire photo. This sort of analysis will easily reveal that something has been added to or removed from a photograph, but if something has been copied within a photograph then other tools will be required.

The next step was to consider whether tools such as Photoshop were used - these introduce distinct artifacts that are peculiar to the brand of software used. After processing experts can visually identify which software has been used.

Another anomaly that can be introduced is varying colour spaces, which is what the Dr used to detect the lottery fake. Altered parts of the photo will be revealed by detecting changes in the colour values used in different parts ofthe photograph.

The moral is that you need not accept defeat in the face of what your client tells you is a digitally altered photograph - you should consider calling in the experts.

First published in the Journal of the Law Society of New South Wales, May 2012. © 2012 Andrew Calvin, Sydney, Australia