2 cissp ® Official Study Guide Eighth Edition

High-Bandwidth Digital Content Protection (HDCP)
Provides DRM protection for con-
tent sent over digital connections including HDMI, DisplayPort, and DVI interfaces. While 
this technology is still found in many implementations, hackers released an HDCP master 
key in 2010, rendering the protection completely ineffective. 
Advanced Access Content System (AACS)
Protects the content stored on Blu-Ray and HD 
DVD media. Hackers have demonstrated attacks that retrieved AACS encryption keys and 
posted them on the internet. 
Industry publishers and hackers continue the cat-and-mouse game today; media compa-
nies try to protect their content and hackers seek to gain continued access to unencrypted 
copies.

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Applied Cryptography 
261
 E-book DRM 
Perhaps the most successful deployment of DRM technology is in the area of book and 
document publishing. Most e-books made available today use some form of DRM, and 
these technologies also protect sensitive documents produced by corporations with DRM 
capabilities. 
All DRM schemes in use today share a fatal flaw: the device used to access 
the content must have access to the decryption key. If the decryption key 
is stored on a device possessed by the end user, there is always a chance 
that the user will manipulate the device to gain access to the key.
Adobe Systems offers the Adobe Digital Experience Protection Technology (ADEPT) to 
provide DRM technology for e-books sold in a variety of formats. ADEPT uses a combina-
tion of AES technology to encrypt the media content and RSA encryption to protect the 
AES key. Many e-book readers, with the notable exception of the Amazon Kindle, use this 
technology to protect their content. Amazon’s Kindle e-readers use a variety of formats for 
book distribution, and each contains its own encryption technology.