Digital Rights Management

A brief introduction

November 2010 Rajaram Pejaver [email protected]

Note: The views presented here are solely those of the author and do not necessarily reflect any views of any MSO. Please contact the author if you have comments or any objections regarding the content.

Outline Digital Rights Management

         CA vs. DRM Definitions The Players The Technologies Apple Fairplay Typical Cable CA Microsoft PlayReady DECE UltraViolet Issues & Open Questions

Outline

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CA vs. DRM What’s the difference?

While both are used to protect content,       “Conditional Access” is the term

typically

used in Cable & Satellite TV.

The operator has control over the STBs and the software on them.

  Connectivity between STBs and Billing  Systems are well defined and reliable.

Simple model: Subscriber either gets to watch HBO or not.

The media being controlled is limited to video.

In general, the requirements on the architecture are much simpler.

   “Digital Rights Management” is the term

typically

used for Internet based systems.

The ecosystem is wild and dynamic with little control and many more threats.

Connectivity to DRM License servers over the Internet is much less reliable.

DRM supports many more usage options and modes (disconnected, rights transfer.) DRM is expected to protect more than just video.

As we will see, the architecture can be horribly more complex.

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Definitions What is this all about?

   Digital Rights Management: – A way to limit access to content to Authorized users.

– A Technology for Distributors to Control Use of Content.

Which Distribution Models use DRM?

Distribution

Intra Company

Technology

Encryption

Examples

Documents, Sales data, … Limited / Corporate Consumer License keys 

DRM

 Software, Garmin Map data, … Video, Music, books… Content: “Soft” products that can be stolen, including – – Video: Movies, Seminars, … Audio: Music, … – – Software: Games, programs.

Books: Soft books, …

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Definitions more terms

 Control over content: – – – – – Copy control: How many times can an item be copied (like CCI bits.)     Never.

N times (typically N = 1) Freely, within domain (typically Domain == devices in a household.) Really freely, anywhere, to the Internet, i.e. no copy control.

Expiry date on content   Usually varies from 90 minutes to 2 days.

How many times can it be watched?

What device is used to watch it?

 iPod like device or Home Theater PC.

 Device usually has special player software to interpret DRM.

What time of day? (business hours, evenings, …) Who can watch it (user authentication required.)

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The Players Where are they coming from?

    Content Distributors: – Copy & Viewer Control.

They care most about protecting content

Vendors of CE Equipment: –

They care about most about profits

Stable DRM standards so that they can build products.

– Reasonable DRM licensing terms.

Consumers: –

Just wanna have fun

Flexibility in choosing content providers, equipment, delivery channel.

– – Replay reliability & ability to back up purchased content.

Privacy of usage.

MSOs (Delivery Channel) – –

Stuck in the middle

Goal: just to keep all other players happy.

DRM is really not an MSO’s war; they do it only because they have to.

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The Technologies Everyone has something to say.

   DRM Technologies from the past – – – CSS for DVDs AACS for DVDs BD+ for BluRay – Royally hacked (remember DeCSS?) – Practically hacked.

– Mostly hacked.

Current DRM Technologies – Apple FairPlay (in iTunes) – – – Microsoft PlayReady (in Zune, SilverLight.) Adobe Flash Access (Flash streams.) Marlin (PS3), Widevine (NetFlix), … Upcoming Technologies.

– DECE’s Ultraviolet: "Digital Locker" by Neustar.

–  Comcast is part of DECE.

Disney’s KeyChest.

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Apple iTunes Fairplay Used for video & books only, not for audio.

    Content in MP4 container file is encrypted with a AES MasterKey.

When a user purchases a title: – A random UserKey is created and stored in the user’s account at Apple.

– – – MasterKey is encrypted with a random UserKey and added to MP4 file.

MP4 file is sent to user’s device.

UserKey is sent to iTunes repository on user’s device.

When user wants to play title: – – UserKey is retrieved and used to decrypt MasterKey.

MasterKey is used to decrypt content.

When user wants to copy or transfer title to another device: – – – – User may need to first de-authorize existing device to stay within limits.

Apple checks for the 5 device limit.

Apple sends a copy of UserKey to device.

Apple sends a copy of encrypted content to device.

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Apple iTunes Fairplay In animated action.

Content A MasterKey A User 1 Key A MasterKey & Encrypted Content A Stored on Apple Servers MasterKey User 1 Key A Encrypted MasterKey Encrypted Content UserKeys are stored in an Apple database Encrypted file User 1 Key A iTunes repository User 1 Key A

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Typical CA system Conceptually similar, but simpler than DRM

 CableCard (aka POD, aka M-Card / S-Card) – – – Does all the decryptions.

Has a unique User Key preprogrammed into it.

Stores all keys: User Key + a key for each authorized Service.

User Key EMM Encrypted Service Key All EMMs for each CableCard are retransmitted OOB every ~10secs.

ECM Service Key Encrypted Control Word ECMs are retransmitted inband every ~2secs, in separate PES.

Video Control Word Encrypted Video Stream Control Word (Video encryption key) is changed every ~2secs.

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Microsoft PlayReady Originally intended for mobile devices.

      Used by Netflix (v2) for video content Used by Microsoft SilverLight for active web content.

It supports a wide variety of business models.

– subscriptions, rentals, purchases, gifting, pay-per-view and preview.

Allows – ‘Side-loading’ between devices in user’s domain.

– – Streaming.

‘Superdistribution’, users forward content, but receiver has to pay to access.

Much more intelligence ‘in the cloud’ – Needs connectivity to ‘cloud’ servers.

– Much more susceptible to glitches in service.

Uses a lot of Public Key Crypto.

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Microsoft PlayReady Too many things in the clouds.

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DECE UltraViolet Digital Entertainment Content Ecosystem

    Members include: – Adobe, Alcatel-Lucent, Best Buy, CableLabs, Cisco, Comcast, Cox Communications, Fox Entertainment, Hewlett-Packard, Huawei Technologies, IBM, Intel, Microsoft, Motorola, Nagravision, NBC Universal, Sony, DivX, Dolby, DTS, Nokia, Panasonic, Paramount Pictures, Philips,… Combination of five existing DRM technologies: – Adobe Flash Access, CMLA-OMA V2, Marlin DRM Open Standard, Microsoft PlayReady and Widevine.

Basic idea: – – – Content encrypted with one MasterKey.

File contains MasterKey protected five ways.

 Note: I said “protected”, not just “encrypted” System is five times more vulnerable?

Content encrypted with MasterKey MasterKey protected with CMLA Nonparticipants: – Apple FairPlay, – Disney KeyChest. MasterKey protected with Flash MasterKey protected with PlayReady MasterKey protected with Marlin MasterKey protected with WideVine

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Issues & Open Questions When will it all go away?

      Watermarking – Need to indelibly associate a copy with a purchaser.

Fingerprinting – Associating a copy with its creator.

Revocation of rights – The amazing Amazon story.

Transferring rights – Users selling & trading content.

Secure audio & video paths – Does not stop piracy.

It is a never ending chase… – Every system will be hacked.

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Thank you for listening!!

Now get back to work

 My solution?

– – Make most content affordable.

So that it is not worth the effort to hack it for profit.

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