Tuesday, May 17, 2005

Star Wars in Digital

Tom Keating - VoIP Blog

Star Wars "digital" is a viewing experience like no other. George Lucas set the standard in 100% digital movie making with Star Wars Episode I - The Phantom Menance. It was my first digital movie experience where I didn't see any splices (black spots in upper right corner) along with the often corresponding "pop" sound nor did I see any dust particles on the film causing graininess or any other analog film artifacts caused by wear and tear on the celluloid. (Analog film splices and wear & tear affects the overall video quality and the sound quality.) When a movie is digital, it's digital all the way up to the point that the film is projected onto the screen.
Now, with the impending launch of Star Wars III - Revenge of the Sith, it is interesting to examine the technology used to transmit a digital film to a digital movie projector which is then projected onto the movie screen. Did you know they actually send the theaters a hard disk drive with the movie on it in encrypted format? Did you know that each frame has its own encryption key so if you unencrpyt one frame, you still have many more frames to go?

I had a friend that worked at a movie theater, so I got "back stage" access to where the projectors are located. I remember the worse thing that could happen is called a "brain wrap" A brain wrap is where the film gathers like a tossed salad on the platters and which essentially brings the movie going experience to a screeching halt. You're probably thinking there is nothing worse than being in the audience when this happens, right? Well, try being the guy who has to detangle this mess and resplice any broken splices quickly before the movie audience storms out or comes looking for you with pitchforks and torches!
Check this out this timely article about Star Wars and movie encryption from Publish:
When a digital film is sent and received in an encrypted fashion, there have to be methods of delivering and utilizing decryption keys to unlock the content.
A part of the key exchange is DRM (digital rights management), which establishes the rules for using the content. All of today's key management systems use some form of DRM to control access and use of the encrypted content. A DRM system allows the owners to distribute their films in a controlled way.
The owner specifies in which ways and under which conditions each cinematic asset may be accessed (digital rights, licensing), and the DRM system will try to ensure that each asset can only be accessed as specified by the owner.
The same DRM system can also be used to distribute films over the Internet. For example, a film studio may specify that each film may be shown in a licensed cinema for a given period starting at a given time.
"It's a difficult issue," said Walt Ordway, chief technology officer for the Digital Cinema Initiatives, a limited liability company that was established in March 2002 and whose members include Disney, 20th Century Fox, MGM, Paramount, Sony Pictures Entertainment, Universal and Warner Bros.
DCI just completed its final draft of standards in March of this year. This document establishes and documents specifications for an open architecture for digital cinema components that ensures a uniform and high level of technical performance, reliability and quality control, as well as addressing security concerns for this digital medium.
"This biggest issues now are over fingerprinting and watermarking, and we need to be careful. How do we set those standards without telling the bad guy how to do it?" Ordway added.
Fingerprints are used to enforce content copyright by enabling the copyright owner to trace back the source of a piracy act. An example would be that all users are given different copies of the content, such as now via a hard drive sent to the theater, where each copy contains a fingerprint—a user-specific watermark. If an unauthorized client redistributes the fingerprinted content, its uniqueness is used to trace back to the offending exhibitor.
Ordway declined to talk specifics about what is in the proposed standards but, according to other sources, the main topics around security that will be addressed are:
• Having security managers at the theaters
• Forensic features to help trace illegal use of content
• Requirements for distribution—link encryption
• Requirements for equipment implementation
• Encryption keys that work on a permission basis with time/date stamps and the management of all those encryption, decryption keys.
Right now, AES-128, the same encryption that banks use for online transfer of information, is what distributors use to secure the digital movie, according to Brian Claypool, senior product manager of cinema for Christi Digital Systems, maker of digital projectors used in about two-thirds of digital cinemas in the United States today.
Advanced Encryption Standard (AES), a Federal Information Processing Standard (FIPS), is an approved cryptographic algorithm that can be used to protect electronic data. The AES algorithm is a block cipher that can encrypt and decrypt digital information. The AES algorithm is capable of using cryptographic keys of 128, 192 and 256 bits.
What makes this encryption more impressive for films is that each frame is encrypted, according to Claypool. "Every frame is encrypted, so if somebody were to get lucky even once on the encryption, they'd only get one frame of the movie," Claypool said. "At the theaters, all they have is an encryption key that allows them to tell the hard drive it's OK to play the movie via the projector. It's just impossible to steal a movie."
Technicolor Digital Cinema, the company responsible for the distribution of Star Wars Episode III: Revenge of the Sith, is handling all content preparation for the movie, including the encryption.
The film is shipped to a theater on a hard drive, according to Technicolor Digital Cinema President Ahmad Ouri. Once it's been confirmed that the theater has received the encrypted film and loaded it onto a server, the encryption key is then delivered separately. "The film is useless without the key, and the key just tells the projector it's OK to show the film." In other words, it does not allow the movie to be copied in any way off the server." more...


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