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25.4.2014 : 0:29

HDCP Cracked !(?)

HDCP is a content protection scheme designed to eliminate the possibility of intercepting encrypted high definition digital data midstream between the source and the display, developed by Intel Corp. It prevents copying of digital audio and video content as it travels across the DisplayPort, DVI, HDMI, GVIF or UDI etc. connections. HDCP uses a three-stage protection process:

  • Device Authentication and Key Exchange
  • Encryption of Content
  • Key-revocation procedures

In 2001, before the HDCP deployed in any commercial product, a paper revealing cryptanalysis flaws published. According to this paper the linear key exchange is a fundamental weakness and the key swap can break with conspiracy attack (obtaining keys of 39 devices and reconstructing the secret master matrix).

On September 14th 2010, hackers posted in pastebin a HDCP Master Key! The key that protects million of devices and media contents, such as Blu-ray, against redistribution. After 2 days, Intel confirms the authenticity of the key and a few days later a programming group releases an open-source C implementation of the HDCP encryption/decryption algorithm, not very efficient as HDCP designed for hardware, which works and verifies that the leaked key is correct.

But,is this the end of HDCP ?

What we can really do with this master key is to derive keys for devices that do work with the keys produced by Intel’s security technology. Also, theoretically, a nefarious user can capture,decrypt and reproduce media travelling across HDMI cables from one device to another. But the most realistic scenario is to build ‘fake’ devices without Intel’s fees and standards. For example a China’s manufactory can produce Blu-Ray players or repeaters-recorders, capable of connecting in genuine HD-TVs , using the leaked master key, without any aprovement from Intel. Intel on the other hand, declares that need a lot of experience and money to accomplish that and in combination with legal threats against possible frauds HDCP remains and effective component for protecting digital entertainment.


28 November 2010