Securing the Future of Mobile Video
The coming of age for mobile video and TV was perhaps one of the most tangible takeaways from the recent Mobile World Congress (MWC) at Barcelona, amid some of the more futuristic demonstrations around say the Internet of Things and virtual reality.
But anyone drilling down into the detail would soon discover two significant hurdles still need to be overcome before HD quality premium video becomes widely available for mobile users, whether they are accessing over Wi-Fi or cellular 3G/4G networks. The two challenges are broadly quality of service (QoS) and security, which turn out to be more closely related than might seem at first sight.
This connection between QoS and security is embodied in Akamai’s Predictive Content Delivery (PCD) solutions, which were unveiled at MWC and address both these challenges. The fundamental motivation for PCD was that no matter what transmission, modulation and error correction technologies are employed, wireless data communications will always be subject to variations in signal strength, bandwidth, latency and therefore QoS.
Conditions for RF (radio frequency) transmission vary greatly within a cell or hot spot and users move about within them, so consistent QoS over the air is virtually impossible to guarantee. The ability to apply adaptive bit rate streaming (ABRS) mechanisms can be compromised in particular by varying latency of TCP connections over mobile networks.
PCD overcomes this by taking account of individual viewing preferences and downloading and pre-positioning the most popular titles on each subscriber’s handset during pre-determined lower bandwidth consumption times.
Because storage on smartphones and even tablets is limited, it is important to have intelligent algorithms for working out which movie titles or TV shows each user is most likely to be interested in on the basis of known viewing habits and that is embodied in Akamai’s PCD.
But pre-positioning immediately amplifies the security risk, because any stored content is potentially vulnerable to piracy. That is where the connection between mobile QoS and security comes in and why Verimatrix as a content protection specialist was integrated into PCD applications.
For premium rights owners such as the movie studios to allow their content to be pre-positioned on users’ devices one fundamental condition had to be met. This was that downloaded content must be just as secure as streamed, protected by the same trusted encryption mechanisms. Only then would they allow the same access rights for each.
Our integration for security with PCD therefore had to be effectively the same as for streamed content. To achieve this we had to ensure, firstly, that the stored content was held in a secure container on the user’s device and only decrypted upon playout at the time of consumption, as happens with streaming, leveraging the same HLS and DASH standards.
Then, secondly, to enforce this, the decryption keys, which only consume a small amount of bandwidth in any case, are only delivered when the user decides to play the content. No confidential information is stored locally on the device and there is no window of opportunity for interception or capture of unencrypted data any more than there is with live streaming. Users get not only the benefit of guaranteed QoS but also potential to use their mobile handset as a portable DVR, which could then mirror the content to a big screen.
We are not of course arguing that at a stroke we have resolved all security issues associated with premium mobile video. But what we in partnership with Akamai have achieved is to bring mobile download onto the same security level as streaming so that it can be established as a long term solution to the conundrum of mobile QoS.