Encryption and Digital Rights Management A look at encryption technologies and their role in protecting intellectual property rights in the digital age.

We will be examining Copyrights Audio DRM Video DRM FairPlay DVD/CSS Blu Ray/ AACS (BD+)

Digital Rights Management Control access to protected material Video Audio E-Book Video Games

Whose rights? Copyright Protection Protection of original works in a tangible medium of expression Protects original works of authorship including literary, dramatic, musical, and artistic works, such as poetry, novels, movies, songs, computer software, and architecture. Do you need to register a copyright? Source - U.S. Copyright Office

Whose rights? Copyright vs. copyleft GNU-GPL What is your boss going to prefer?

Cassette Tapes Early scourge of recording industry Mix Tapes WUEC

Cassette Tapes

Digital Audio DRM - Fairplay Apple Computer DRM system AES encryption Master key stored on Apple server User key stored encrypted are in iTunes

Machine Authorization

Key Exchange When a user buys a song from the iTunes Store, a user key is created for the purchased file. The AAC song itself is scrambled using a separate master key, which is then included into the protected AAC song file. The master key is locked using the user key, which is both held by iTunes and also sent to Apple’s servers.

Playing a protected song iTunes uses the matching user key to unlock the master key stored within the song file. Keys are all encrypted and stored on the authorized iTunes computer, as well as being copied to Apple's servers. When a new computer is authorized, it also generates a globally unique ID number for itself and sends it to Apple. Apple's server sends the newly authorized machine the entire set of user keys for all the tracks purchased under the account. 

Playing on an iPod All keys are downloaded to iPod. Protected songs which do not have keys are not able to be copied to iPod.

Cracking FairPlay – Jon Johansen Song data dumped as a raw stream into a large container file, requiring further processing afterward.  PlayFair, Hymn, JHymn and other derivatives-- intercepts unlocked but not yet uncompressed song files, creating a small, ready to play, unencrypted AAC file. PyMusique, requests songs from Apple's servers and then downloads the purchased songs without locking them, as iTunes would. FairKeys pretends to be iTunes; it requests a user's keys from Apple's servers and then uses these keys to unlock existing purchased songs. Not fully cracked

Digital Audio DRM – Yahoo! What happens when DRM servers go offline?

Early Video DRM - Macrovision Used to protect VHS from recorder-recorder copying Exploits VCR gain control Mechanical work-around VCR-VCR

CSS – Content Scramble System Keys stored on lead-in areas of disc Prevents byte-for-byte copies Requires manufacturers to obtain license Keys for EVERY licensed player encrypted on DVD 40 bit cipher stream Government forbade export of >40 bit ciphers Compromised by brute force attack

DVD Encryption Keys

Linear Feedback Shift Registers Every eight clock cycles, byte is produced.

DeCSS Linux Haiku describing decryption algorithm CSS cracked by Jon Lech Johansen and two others in 1999 A computer fast enough to play a DVD was fast enough to decrypt CSS in real time. Haiku describing decryption algorithm http://www-2.cs.cmu.edu/~dst/DeCSS/Gallery/decss-haiku.txt

Code fragment of DeCSS.

ARccOS DRM protection Advanced Regional Copy Control Operating Solution Proprietary system by the Sony Corporation Added corrupt sectors which DVD players were instructed to skip Some Sony movies were unplayable even on Sony players without firmware update

Blu Ray Encryption AACS BD+ - helped win format war.

Advanced Access Content System

AACS Key Controversy 09 F9 11 02 9D 74 E3 5B D8 41 56 C5 63 56 88 C0 Copyrighted 128 bit number! Take down notices sent by Motion Picture Association of America and AACS Licensing Agent May 1st, 2007: Google search for key: 9410 results May 2nd, 2007: Over 300,000 Playback devices hold binary tree of possible keys. When key is compromised, new discs choose different key.

BD+ Works “on top” of AACS Virtual machine embedded in authorized player Examine the host environment, to see if the player has been tampered with. Verify that the player's keys have not been changed. Execute native code, possibly to patch an otherwise insecure system. Transform the audio and video output. Limit playback of a Blu-Ray disc to the first device in which the disc is played

Slysoft vs. BDA/Macrovision About a three month window between new BD+ and Slysoft’s AnyDVD cracking it. Win for studio.

Analog Hole Always possible to pass digital content through analog device to copy

http://www.math.ucsd.edu/~crypto/Projects/MarkBarry/index.htm http://www.roughlydrafted.com/RD/RDM.Tech.Q1.07/ http://www.any-dvd-clone.com/knowledge/dvd-protection-types.html http://mashable.com/2008/07/26/yahoo-drm-shut-down/ http://en.wikipedia.org/wiki/BD%2B http://en.wikipedia.org/wiki/DeCSS