How to bring Android into the Internet digital home? Article 4 reprint

In this article, we will focus on the challenges in Content Protection/system security and some simple comparisons between Android TV and googletv.

• Challenges5. How to deploy Content Protection:
  • How to deployCa?
  • How to deployDRM?

In article 3, we have already talked aboutCA module integration. Since the CA module is strictly controlled by each CA, and the system integration of the CA module is dominated by CA, there are no technical challenges; more challenges lies in how to standardize ca-related APIs. Compared with Ca and DRM, Android 3.0 adds DRM-related APIs. Figure 1 shows how android3.0 implements the drm api.

Figure 1 implement DRM in Android 3.0

As you can see,Android3.0 implements a set of Java-level DRM APIs and a C/C ++ level DRM manager. The implementation of each specific DRM policy links to DRM manager in Plug in mode. The specific DRM plug in is implemented by various system vendors based on actual needs, while application developers can develop related applications based on standardized DRM APIs.

In implementationIn the process of DRM, trustzone, an arm-level security technology, can reinforce the security of DRM at the hardware architecture level. So what is trustzone? To put it simply, trustzone is a security technology at the system architecture level. It virtualizes the entire SOC into two modes: normal world and security world. In the "safe world" mode, the system can access all resources, including data storage, memory, and peripherals configured as "secure" and "unsecure; in normal world mode, you can only access resources configured as "unsecure. Figure 2 illustrates the trustzone architecture.

Figure 2 trustzone Technology

We can see General operating systems, suchAndroid, Ubuntu, chromeos, windows, and Symbian all run in the "ordinary world", while services requiring security encryption run in the "safe world ", root keys, including encryption, are stored in the "safe world ". Software running in the "normal world" cannot access resources in the "Safe World", including data storage/memory/peripherals configured as "secure. Figure 3 describes how trustzone works from the perspective of system architecture.

Figure 3 system architecture of trustzone

From figure 3, we can see that the devices in the system are divided (Normal) "," secure ", and" switchable. Therefore, trustzone blocks access to "secure" Resources in the "common world" at the system level, and fundamentally enhances the security of the system. A typical example is: on our current smartphone, enter the password through the touch screen, No matter what encryption method is used to pass the password, the data is always flowing in the mobile phone operating system, and there is still a risk of being hack. If trustzone technology is used, you can set the LCD controller to "configurable". When you need to enter a password, you can set the LCD controller to "secure ", in this way, the mobile phone operating system will not be able to access the device, and all data streams will directly enter the "safe world". When the user enters the password, the LCD controller will be switched back to "normal ", in this way, the mobile phone operating system can use it normally.
Figure 4 shows a flowchart of How to Apply trustzone technology to DRM.

Figure 4 Use trustzone to encrypt DRM

Now, we have discussedThe five challenges that android brings into the Internet digital family: Let's take a look at some comparisons between Android TV and googletv.

In fact,Arm partners can deploy Smart TVs with Android as the base in three ways:

First,DirectlyGoogle cooperates with lictv through license to become the leading partner of googletv;

Second,WaitGoogle open-source googletv project;

Third,Open-sourceAndroid versions are customized and transplanted to the TV platform (my four blog posts are centered around this option ).

So,What is the difference between googletv and Android TV?

As we all know,Google TV uses android as the base. The first generation of googletv

Google TV 1.0 uses android2.1 as the base, while Google TV 2.0 of the Second Generation updates Android base to 3.1. According to the latest Android roadmap, Google will form a unified version for three types of products: Phone, tablet, and TV in ice cream sandwich.

Google TV 1.0 was listed last year. Google TV 1.0's software architecture is based on dual-system architecture.Basic: googletv Android system + DTV system. DTV systems are developed by TV system manufacturers and generally choose to reuse existing DTV systems. The googletv system module focuses on WebTV functions and adds control modules for communication with DTV systems.

Although Google TV is based on Android, Google has made a lot of TV applicationsUsed for modification and optimization, including upgrading the browserChrome improves the performance of 2D/3D graphic, Multimedia Framework (dual view supported), flash plug in, new home screen and UI layout. However, due to the dual-system design, googletv does not have a functional module of DTV, but only some communication modules that control the DTV system, including the control of external input. Therefore, before Google TV evolved into a single system, it was difficult for Google TV SDK to support DTV APIs.

SlaveAccording to the development trend of googletv, googletv will evolve into a single system solution. In fact, many arm TV chip partners are already working with Google on the googletv project, and related products will be listed one after another. In addition, Google has plans to gradually release googletv development tools, including googletv SDK and ndk, as well as related CTS and CDD.

In addition, whenWhen arm's partners choose to port android to their own TV/set-top box platforms, we generally recommend that they consider the following two points in Architecture:

First,How to Adapt customized workHow quickly does the Android version change?

Second,WhenHow can Google TV quickly reuse its work on Android TV after it is open-source?

When the above two problems are clearly consideredRisks during Android TV development,

To cope with the rapid changes in the Android version and the open-source possibility of googletv!

Finally, I would like to share with you that today, the emergence of new Internet devices, such as smartphones and tablets, has made people spend less and less time on TV, if TV is not redefined, TV will have no future if TV is not interconnected and smart! In this process, the emergence of android can greatly accelerate the process of Digital Home interconnection and intelligence, so that it can quickly achieve interconnection and integration with other smart devices in the home, to achieve real smart home! (Completed)