DRM interoperability

Gasser and Palfrey (2007) refer to interoperability as “the ability to transfer and render useful data and other information across systems (which may include organizations), applications, or components” in the context of information and communications technologies (ICTs). The DRM interoperability can be defined as the ability to distribute and consume the digital content in a controlled manner across DRM systems, devices, and applications.

Digital content is consumed with purchased rights via an application integrated with a DRM agent of a DRM system on a device. As shown in Figure 3, DRM system can have multiple DRM agents on different devices. A device can install multiple applications and support multiple DRM agents. An application can integrate more than one DRM agent from different DRM systems. From end users’ point of view, DRM interoperability ideally means that specific DRM content with its rights can be consumed by any of their preferred applications on any of their devices (Meléndez-Juarbe 2009). In other words, a DRM system should be invisible to the end users.

Unfortunately, the lack of DRM interoperability has introduced unnecessary usage restrictions to customers (Geer 2004). In order to efficiently address specific interoperability issues of DRM, DRM interoperability is categorized into three levels:

System interoperability means that DRM content and its rights governed by one DRM system can be governed by, and exported to other DRM systems.

Device interoperability means that DRM content and its rights can be transferred to and consumed on other devices; and

Application interoperability means that DRM content and its rights can be consumed by different applications.

As an example illustrated in Figure 4, a user Jack has three devices: Amazon Kindle, iPad, and iPhone. He uses the following e-reader applications to read e-books: a Kindle app on Amazon Kindle, a Kindle app on an iPhone, a Kindle app on an iPad, an iBooks app on an iPad, and an iBooks app on an iPhone. Jack purchased books with those apps. Ideally, all the books Jack purchased should be consumable through any of the e-reader apps on any of his devices. In practice, Jack can only read Kindle books on Kindle apps and iBooks books on iBooks apps. In terms of system interoperability, according to Apple iBooks (2015) “books downloaded from the Kindle Store and other books that aren’t in a DRM-free standard EPUB format aren’t compatible with iBooks.” On the other hand, DRM-protected books from the iBooks store cannot be governed on Amazon Kindle devices (Adner 2014). So there is no system interoperability between DRM systems used by the Kindle store and the iBooks store. In terms of device interoperability, Amazon Kindle does not yet have an iBooks app nor an iBooks DRM agent that can enable other apps to consume books from the iBooks store. Moreover, Apple probably has no interest in providing such an app on the Amazon Kindle (Adner 2014). DRM systems have gradually evolved into tools for consumer lock-in (Kalker et al. 2012). On the contrary, the Kindle app works well with the Kindle DRM protected books on both the iPhone and the iPad besides the Amazon Kindle. Thus, the interoperability is

one-directional rather than bi-directional between the two systems. The DRM system used by the Kindle store provides device interoperability among all Jack’s devices while the DRM system used by iBooks store only covers interoperability among Apple devices. In terms of application interoperability, Kindle apps can consume books only from the Kindle store while iBooks apps can consume books only from the iBooks store. Neither of the DRM systems offers application interoperability to permit Jack to choose freely an e-reader app he prefers.

Amazon Kindle

Figure 4. An example of DRM interoperability issue

Generalized from the real-life example, Figure 5 presents different levels of DRM interoperability. System interoperability exists between DRM systems X and Z.

Device interoperability between A and B is achieved by DRM system X with a separate DRM agent A(X) on device A and B(X) on device B. Application interoperability between B1 and B2 is achieved by DRM system X with its DRM agent B(X) integrated into both applications. Once system interoperability is achieved between two systems, device interoperability and application interoperability can be improved as well. As illustrated in Figure 5, the existence of system interoperability between X and Z also indirectly achieves the device

DRM interoperability can be achieved in different manners. System interoperability needs two DRM systems to interact with each other. System interoperability can improve the application and device interoperability as the device and application coverage from DRM systems combined is larger than individual coverages of any DRM systems. On the other hand, the application interoperability and device interoperability can be achieved within one DRM system by implementing the DRM agents for the target devices and integrating them into the target applications.

Figure 5. Different levels of DRM interoperability

Compared with the device and application interoperability, the benefit of system interoperability appears to be not as obvious as the benefits that the other two offer to end users. Nevertheless, the impact of system interoperability can be profound.

Firstly, end users have the freedom to purchase rights to the desired content from any preferred retailer if system interoperability is in place for the DRM systems utilized by those retailers. As rights can be exported from one system to another, end users can choose the retailer that offers the best price and services. Secondly, the purchased rights and its content can be independent of a specific DRM system.

Without system interoperability, an end user is essentially locked with the device and application options provided by the specific DRM system (George and Chandak

2006). Shifting to other device or application options implies losing access to all the purchased rights to the content. Moreover, when the original retailer ceases to exist, system interoperability protects end users from the risk of losing the purchased rights and their related content as end users have options to shift to another DRM system.

Thirdly, system interoperability reduces the cost of a DRM solution by reducing the total industrial effort to provide device interoperability and application interoperability. Once interoperability exists among DRM systems, DRM agents can be shared, and there is no need to have separate DRM agents for each DRM system on each device to provide the same level of device interoperability. The less DRM agents, the less integration work, is needed for applications to provide the same level of application interoperability.