MULTIMEDIA SYSTEMS IREK DEFEE MULTIMEDIA SERVERS, DRM and the MPEG-21 Standard

MULTIMEDIA SYSTEMSIREK DEFEE

MULTIMEDIA SERVERS,DRM and the

MPEG-21 Standard


• MULTIMEDIA HAS TWO BASIC

REQUIREMENTS FOR STORAGE AND

SERVERS:

- LARGE AMOUNT OF DATA STORED

(GIGABYTES FOR ONE ITEM)

- DATA OUTPUT IN (HIGH

BANDWIDTH) STREAMS

THIS IS CALLED STREAMING


• STREAMING MEANS THAT EACH USER GETS CONTINUOUS DATA

STREAM, PRECISELY SYNCHRONIZED

IN TIME, FROM THE STORAGE AND

THE SERVER

THE STREAM CAN BE HIGH BANDWIDTH –

FOR EXAMPLE 1, 3, 4 Mb/s for TV, 6-10 Mb/s for HDTV


• THIS PUTS HIGH DEMANDS FOR THE

STORAGE AND SERVER SYSTEM:

Assume there are 100 users and each wants

to get a movie stream compressed to 3 Mb/s. This means total system output capacity should be 300 Mb/s.

This should be streaming capacity, that is 100 streams of 3 Mb/s, each flowing with constant packet flow and no breaks


• MULTIMEDIA DATA REQUIRE

LARGE STORAGE.

EXAMPLE: MOVIE STREAM OF 4 Mb/s

FOR 2 HOURS NEEDS 3.6 GB STORAGE

100 MOVIES REQUIRE 360 GB

LARGE SYSTEM COULD HAVE E.G.

10 000 USERS WITH 1000 MOVIES,

A BIG SYSTEM IS NEEDED

HOW TO BUILD SUCH A SYSTEM?


• FOR MULTIMEDIA MASS STORAGE

IS REQUIRED BUT DEVICES LIKE TAPE, CD, DVD ARE NOT SUITABLE BECAUSE THEY CAN OUTPUT ONLY

ONE STREAM AT A TIME

• HARD DISCS ARE MORE SUITABLE

- STORAGE IS HIGH AND GROWING

- OUTPUT CAPACITY IS HIGH


• IN STANDARD COMPUTER SYSTEMS

STORAGE IS BASED ON HARD DISCS

WHICH ARE MECHANICAL DEVICES

THOUGH SEMICONDUCTOR DISKS

ARE AVAILABLE BUT EXPENSIVE

• HARD DISC ARE ESSENTIALLY SERIAL IN NATURE SINCE THEY

HAVE HEADS WRITING AND READING ON A DISC PLATTER


CONSTRUCTION OF HARD DISC:MAGNETIC MATERIAL ON PLATTERS IS ARRANGEDIN TRACKS.HEADS ARE READING/WRITING BY CHANGINGMAGNETIC ORIENTATION


• HARD DISC CAN THUS OUTPUT

ESSENTIALLY ONE OR FEW STREAMS

BUT WITH HIGH BANDWIDTH (OVER

100 MB/sec)

• BECAUSE HARD DISC MECHANICAL PARTS MOVE VERY QUICKLY, HARD DISC CAN OUTPUT MANY STREAMS OF LOWER BANDWIDTH BUT OUTPUT CAPACITY WILL BE LIMITED


• CURRENTLY SINGLE DISC DRIVES

HAVE CAPACITY UP TO SEVERAL

TERABYTES (1 TB=1000 GB)

STREAMING CAPACITY IS IN THE

RANGE OF 100-200 2-5 Mb/s STREAMS

OUTPUT CAPACITY DEPENDS ALSO ON - THE OPERATING SYSTEM,

- THE INTERNAL PC BUS AND

- I/O – RELATED TO NETWORKING


• HARD DISC PARAMETERS:

-STORAGE SIZE: TODAY IT IS 3 TB, GROWING

1TB PER YEAR? (WE DO NOT KNOW WHEN IT WILL FINISH, NEVER?)

• Platters rotational speed - 7200 RPM • Interface – SATA - 3 Gb/sec and 6 Gb/sec• Sustained data transfer rates – 150 MB/s• Random read/write: 75/150 operations per second• Average data seek time – 6 ms writing 12 ms reading


• THUS THE DESIGN OF STORAGE SYSTEM FOR MULTIMEDIA DATA

MUST TAKE INTO ACCOUNT LIMITS

ON STREAMING CAPACITY OF HARD

DISCS

• STREAMING CAPACITY DEPENDS ON

- MECHANICAL PROPERTIES

- FILE SYSTEM ORGANIZATION


DISC HEAD MUST BE POSITIONED TO START READING, NECESSARYT HEAD MOVEMENT WILL DEPEND ON THE LOCATION OF A TRACK. AVERAGE TIME MIGHT BE E.G´. 8MS. WHEN HEAD IS POSITIONED IT CAN STARTREADING, THE SPEED CAN BE E.G. 100 MB/S

FOR STREAMS, ONE HAS TO READ AS MANYHIGH BANDWIDTH STREAMS AS POSSIBLE.

E.G. 180 STREAMS WITH 3 Mb/s EACH


IN PRACTICE THERE WILL BE MANYPARAMETERS IN THE DESIGN OF MEDIA SERVER-MEMORY BUFFERS-NETWORK INTERFACES-OPERATING SYSTEMTHEY NEED TO BE OPTIMIZED FOR MAXIMUM PERFORMANCE

IN PRACTICE DISCS HAVE THEIR OWN RAM BUFFERS, AND THERE

ARE ALSO RAM BUFFERS IN

MEMORY PLUS

NETWORK INTERFACE BUFFER


EXAMPLE OF MEDIA SERVER DESIGN:

SERVER BASED ON PC WITH SATA BUS

HARD DISC WITH 150 MB/s TRANSFER SPEED

NETWORK INTERFACE: GIGABIT ETHERNET 1000Mb/s

HOW MANY 4 Mb/S STREAMS IT CAN SUPPORT?

WE HAVE READING ACCESS LIMITED TO 75 /SEC

SO IT WILL BE ABOUT 75 STREAMS IN PRINCIPLE

PROCESSOR AND OPERATING SYSTEMS ARE ENOUGH FAST SO NO PROBLEM HERE


THUS, THE MEDIA SERVER PERFORMANCEMIGHT BE LIMITED BY VARIOUSCOMPONENTS OF PC SERVER ARCHITECTURE:- HARD DISC PROPERTIES (READING STREAMS)- BUS FROM HARD DISC TO COMPUTER (SATA)-NETWORK INTERFACE – E.G. 1000 Mb/s

TO THIS ONE MAY ADD THE SPEED OF PROCESSOR AND OPERATING SYSTEMBUT THIS SHOULD NOT BE A PROBLEM

THE QUESTION IS: HOW TO INCREASE THEHARD DISC STORAGE SPEED?


HERE WE SEE STANDARD COMPUTER ARCHITECTUREIT COULD BE A PC WITH SATA HARD DISCDEVICE INTERFACE PLUS PROCESSOR

IF WE CONNECT MORE DISCS, THIS WILL INCREASESTORAGE SIZE BUT NOT ITS SPEED

WE NEED TO USE SOMETHING ELSE AND THIS IS... RAID ->


STRIPING AND RAID

• A METHOD FOR INCREASING

STORAGE AND OUTPUT CAPACITY

IS BY CONNECTING HARD DISCS IN

PARALLEL AND STRIPING FILES

ON THEM


STRIPING AND RAID

DISC

DISC

DISC

SYSTEM

CONTROLLER

THREE DISCS = THREE TIMES HIGHER OUTPUT

FILE

STRIPING


• STRIPING MEANS THAT FILES ARE READ AND WRITE IN BLOCKS WHICH ARE DISTRIBUTED OVER DISCS• EXTERNALLY THE SYSTEM WILL

LOOK LIKE ONE BIG DISC

WITH N DISCS WE COULD HAVE NTIMES HIGHER OUTPUT CAPACITYAND N TIMES BIGGER STORAGE


BLOCKS OF DATA ARE STRIPED AMONG DIFFERENT DISCSOPERATING IN PARALLELIN THIS WAY SPEED OF READINGAND WRITING CAN BE INCREASED

STRIPING PRINCIPLE


• THERE IS ONE ADDITIONAL IMPORTANT ADVANTAGE:

WITH THE INCREASING STORAGE

RELIABILITY IS GOING DOWN

• WITH STRIPING ONE CAN BUILT-IN

ERROR TOLERANCE

THIS CONCEPT IS CALLED RAID =

REDUNDANT ARRAY OF

INEXPENSIVE DISCS


RAID

DISC

DISC

DISC

SYSTEM

CONTROLLER

PARITYDISC

ERROR

CORRECT. DISC

ADDED DISCS FOR ERROR CONTROL

FILE

STRIPING


• RAID DISC ARRAYS ARE CLASSIFIED

IN SEVERAL LEVELS

RAID 1 - DISC MIRRORING (EACH

DRIVE IS DOUBLED)

RAID 2 - BIT INTERLEAVING AND

PARITY/ERROR CORRECTION

RAID 3 - BIT INTERLEAVING WITH

XOR PARITY – SINGLE DRIVE

DEDICATED TO PARITY


• RAID 4 – BLOCK INTERLEAVING

• RAID 5 – BLOCK INTERLEAVING

WITH PARITY

DISTRIBUTION

• RAID 6 – FAULT TOLERANT SYSTEM

DISC FORM A MATRIX FOR ROW AND COLUMN PARITY – FAULTY DISC CAN BE IDENTIFIED AND REPLACED

• RAID 7 – HETEROGENOUS SYSTEM

SUPPORTS MULTIPLE HOSTS


OVERALL ARCHITECTURE OF MACHINE WITH RAID DISC ARRAY AND NETWORKADAPTERSRAID CAN BE IMPLEMENTED IN SOFTWAREOR IN HARDWAREHARDWARE RAID WILL PUT LESS LOAD ON THE PROCESSOR AND SYSTEM


• DISC ARRAYS CAN BE BUILT WITH

TENS OF TERABYTES.

THUS ENOUGH STORAGE CAPACITY EXISTS FOR STORING VERY LARGE COLLECTIONS OF MULTIMEDIA DATA


• HOW TO BUILT LARGE MEDIA

SERVERS? IMAGINE A SYSTEM

SERVING ONE CITY WITH HUNDREDS, THOUSANDS, MORE USERS

FROM SUCH SERVERS THE REQUIRED

OUTPUT CAPACITY WOULD BE MANY GIGABITS/SEC, E.G. 10 000x4Mb/s=40Gb/s

NO STANDARD COMPUTER HAS SUCH

OUTPUT


• DESIGN OF MEDIA SERVER IS

DIFFERENT FROM STANDARD SERVER BECAUSE STREAMS MUST

HAVE GUARANTEED DELIVERY,

THAT IS STREAMS CAN NOT SLOW

DOWN OR STOP.

• THUS, MEDIA SERVERS MUST BE

DESIGNED FOR THE PROJECTED

NUMBER OF USERS


WE CAN USE MANY SERVERS INSTEAD OF ONE

CREATING A SERVER FARM OR “CLOUD”

WE CAN USE RAM MEMORY BUFFERING CACHE FOR STREAMS – FROM THE RAM CACHE WE CAN SERVER MORE STREAMS THAN FROM HARD DISC


• SOMETIMES WE CAN APPLY MULTICASTING IN WHICH MANY USERS GET THE SAME STREAM – ONLY A SINGLE STREAM IS RETRIEVED FROM HARD

DISC SOMETIMES APPLICABLE


• WE COULD ALSO DISTINGUISH BETWEEN PEAK DEMAND AND AVERAGE DEMAND FOR STREAMS, E.G. AVERAGE DEMAND CAN BE 10%

OF PEAK

WE SHOULD TAKE INTO ACCOUNT

THAT MANY USERS MAY RETRIEVE

THE SAME CONTENT ( PERHAPS DELAYED SLIGHTLY IN TIME)


RAID STORAGE

MEDIA SERVER DESIGN:

STORAGE BUSE.G. SATA III

PROCESSOR(S)

RAM BUFFERS

NETWORK INTERFACE WITH BUFFER

P... ...P

DATA FROM STORAGE ARE TRANSFERREDTO RAM BUFFERS AND THEN TO NETWORK INTERFACETHE BIGGER THE RAM BUFFER, THE MORESTREAMS COULD BE SUPPORTED BY THESERVER BUT IT WILL TAKE MORE TIME TOFILL THE BUFFER SO THE START OF CONTENT WOULD BE DELAYED.THUS RAM BUFFERS CAN NOT BE TOOBIG IN PRINCIPLE.BUT ONE CAN TRY TO OPTIMIZE THESYSTEM CREATING BIGGER BUFFERSWHEN SYSTEM IS NOT LOADED MUCHAND SHORTER BUFFERS WHEN THEREIS HIGH LOAD.OVERALL SERVER OPTIMIZATION MIGHTBE STILL AN OPEN PROBLEM(OR COMERCIAL SECRETS ARE HERE?)

PCIeBUS


ONE IDEA IS TO DESIGN SPECIAL BIG MACHINE WITH VERY MANY BUSES,PROCESSORS, AND CONNECTED TO BROADBAND NETWORK, WE SHOULD TAKE INTO ACCOUNT THAT NETWORKBANDWIDTH FROM COMPUTERS IS LIMITED, E.G. GIGABIT ETHERNET IS FASTEST PRACTICAL INTERFACE TODAY, 1000 Mb/s THOUGH SEVERAL SUCH INTERFACESCAN BE USED AND THERE IS ALSO 10 Gb/s INTERFACE

THUS, A BIG MACHINE WOULD NEEDTO HAVE MULTIPLE NETWORK INTERFACESIT WOULD BE VERY EXPENSIVE


• SUCH DEDICATED MACHINES

WOULD REQUIRE:

- MULTIPROCESSING

- MULTIPLE I/O TO THE NETWORK

- VERY BIG DISTRIBUTED STORAGE

MACHINE WOULD BE VERY EXPENSIVE AND NON-STANDARD


• THE REAL DIFFICULT PROBEM IS WHEN MANY DIFFERENT STREAMS NEED TO BE RETRIEVED AND SEND

• IN THE DESIGN OF MEDIA SERVERS

THERE ARE TWO CHOICES

- DEDICATED MACHINES

- MULTIPLE SYSTEMS WITH

CENTRAL CONTROL


• DEDICATED MACHINES

- MULTIPROCESSING

- MULTIPLE I/O

- DISTRIBUTED STORAGE

EXPENSIVE AND NON-STANDARD


•ANOTHER IDEA: MULTIPLE STANDARD MACHINES. MEDIA FILES ARE DISTRIBUTED ALONG A NUMBER OF SERVERS WHICH HAVE COMMON CONTROL

HERE THE PROBLEM IS THAT STORAGEREQUIRED MIGHT BE BIGGER (OFTEN USEDMEDIA STREAMS ON MANY SERVERS


• MULTIPLE SIMPLE MACHINES

WOULD BE MUCH CHEAPER THAN

A SINGLE BIG SERVER. SINGLE

MACHINES CAN BE LOCATED NEAR

USER LOCATIONS.

FOR EXAMPLE, SINGLE SERVER WITH GIGABIT INTERFACE COULD

SERVE ABOUT 200 USERS, ONE WOULD NEED A HUNDRED OF SUCH

SERVERS FOR 20 000 USERS


HOWEVER, THEN EACH SERVER WOULD NEED TO HAVE STORAGE WITH ALL MEDIAFILES, SO OVERALL THERE WOULD BE MUCH MORE STORAGE NEEDED THAN IN A SINGLE BIG SERVER

BASIC IDEAFOR MANYSIMPLE SERVERS


ANOTHER CONCEPT – MULTIPLE SERVERSCONNECTED VIA NETWORK. THE NETWORKCAN BE UED FOR FILE TRANSFER BETWEENSERVERS. STORAGE CAN BE ADAPTED FORTHE DEMAND (ONLY POPULAR STREAMS WOULD BE ON MORE SERVERS, SAVING STORAGE)


YET ANOTHER SYSTEM: STORAGE AND SERVERS ARE SEPARATED, THEN SERVERSWILL BUFFER AND REPLICATE STREAMSWHICH ARE IN DEMAND


• SUCH SYSTEMS CAN BE ASSEMBLED

QUITE EASILY BUT REQUIRE

- USER MANAGEMENT

- STREAM MANGEMENT

- CONTENT MANAGEMENT

- OVERALL PERFORMANCE

OPTIMIZATION

THIS HAS TO BE COORDINATED WITH

NETWORKING


IN FACT MEDIA SERVER IS MUCH MORE THANJUST SENDING STREAMS: USERS WILL CONNECT/DISCONNECT, SEARCH APPLICATIONS-ALL THIS NEEDS TO BE MANAGED.THERE WILL BE MANY CONTROL FLOWS


THE SYSTEMS WILL OFTEN REQUIRE PAYING,THUS EXTENSIVE DATABASE OF USERS,PAYMENTS, BILLING, AUTHORIZATION, AUTHENTICATION WILL BE NEEDED.ENCRYPTION OF DATA WILL BE NECESSARY


IF USERS HAVE ACCESS TO BROADBANDNETWORK OTHER APPLICATIONS MIGHTBE ATTRACTIVE: WEB ACCESS, OWN BROADCAST,VIDEOTELEPHONE, VIDEO CONFERENCING


ON THE OPERATOR SIDE, FULL ADMINISTRATIONIS NEEDED:-SYSTEM OPERATION MONITORING-ADMISSION CONTROL (NEW USERS)-CONTENT UPDATES


CONCLUSIONS:-MEDIA SERVERS ARE ESSENTIAL COMPONENT OF MULTIMEDIA SYSTEMS-THEY DESIGN NEEDS TO TAKE INTO ACCOUNT STREAMING GUARANTEES-STORAGE, NETWORKING, PROCESSOR REQUIREMENTS ARE QUITE SUBSTANTIAL-LARGE SOFTWARE IS NEEDED FOR -COMPLETE COMMERCIAL SYSTEMS

DIGITAL RIGHTS MANAGMENT

What is missing?

Here we see scheme of networked multimedia system, red part is hardware, blue is content, green is software for running it.

WHAT IS MISSING IN THIS PICTURE?The missing part is CONTENT PROTECTION AND DRM

• DIGITAL CONTENT (AUDIO,

VIDEO, GRAPHICS, IMAGES)

CAN BE EASILY COPIED, TRANSMITTED AND DISTRIBUTED

THIS HAS GREAT ADVANTAGES AND

BUSINESS POTENTIAL

• BUT DIGITAL MEDIA CAN ALSO MAKE BIG PROBLEMS FOR CONTENT OWNERS DUE TO UNAUTHORIZED USE. THEY CAN EASILY LOSE THEIR PROPERTY

• CONTENT OWNERS NEED THUS STRONG PROTECTION

• THUS DIGITAL CONTENT SHOULD

BE PROTECTED AGAINST

UNAUTHORIZED USE

THIS PROBLEM IS KNOWN CURRENTLY

UNDER THE NAME DRM

DIGITAL

RIGHTS

MANAGEMENT

Digital Rights Management (DRM)

= technologies used by publishers or copyright owners to control access to or usage of digital data or hardware, and to restrictions associated with a specific instance of a digital work or device

• can be used – to protect high-value digital assets

– control their distribution and usage

• Ultimate goal:

– persistent content protection against unauthorized access to the digital content,

limiting access to only those with the proper authorization – to manage usage rights for different kinds of digital content (e.g.music files,

video streams, digital books, images)

– different platforms (e.g. PCs, laptops, PDAs, mobile phones)

– control access to content delivered on physical media or any other distribution method (e.g., CD-ROMs, DVDs)

Digital Rights Management (DRM)• Different methods for

- Audio- Video- Internet stores- Documents (Enterprise DRM)

• Digital licenses– the consumer purchases a license with certain rights– A license is a digital data file that specifies certain usage rules (frequency of access,expiration date,

restriction of transfer to other devices, copy permission etc., may combined to try-before-buy) for the digital content

• Several players involved in– E.g. online distribution:

content provider, distributor,

consumer, clearing house - DVD’s manufacturer, replicator, player…

- Consumer: privacy, fair use (research, education..), usability (compatibility, seamless, updates)

EXAMPLE: Apple music store

Buying music from thenetwork means that thecontent has to be protectedagainst copying

• WHAT ARE THE REQUIREMENTS FOR DRM?

- IT SHOULD PREVENT COPYING- IT SHOULD AUTHORIZE ACCESS LIMITED TO: PARTICULAR USER, SPECIFIC TIME, SPECIFIC NUMBER USAGE AND COPIES, ETC.- IT SHOULD FACILITATE PAYMENT FOR CONTENT (E.G. RENEWAL OF RIGHTS)

• ALL REQUIREMENTS FOR DRM ARE VERY DIFFICULT TO SATISFY

• IN PARTICULAR THEY ARE DIFFICULT IF THE DRM SYSTEM WOULD BE STANDARDIZED, THAT IS

IS STRUCTURE IS KNOWN

• THIS IS BECAUSE STANDARDIZED SYSTEM MIGHT BE EASIER TO BREAK THAN SECRET SYSTEM

• IN PRINICPLE DIGITAL CONTENT CAN BE EASILY (?) PROTECTED

BY ENCRYPTION

WHAT IS ENCRYPTION?

THE CONTENT BITS ARE MANIPULATED IN SECRET WAY

BY SOME ALOGRITHM.

• THE ORIGINAL BITS CAN BE

RECOVERED BY REVERSING

THE OPERATION OF THE

ALGORITHM

CONTENT ENCRYPTIONALGORITHM

DECRYPTIONALGORITHM

CONTENT

• BUT SUCH SYSTEM HAS PROBLEMS1. IF ALGORITHM IS KNOWN, EVERYBODY WILL USE IT2. HOW TO CONTROL ACCESS? THAT IS USERS MAY BUY ACCESS FOR SOME TIME AND FOR SOME CONTENT ONLY 3. WHAT TO DO WITH USERS WHICH WILL USE PROPER ACCESS FOR ILLEGAL COPYING?

• THUS THE DRM CONTENT PROTECTION MUST BE MORE CLEVER IT HAS TO BE BASED ON

1. CONDITIONAL ACCESS

2. ENCRYPTION ALGORITHMS

and the newest addition is:

3. REVOCATION OF RIGHTS

• WHAT IS CONDITIONAL ACCESS?

IT IS ACCESS GIVEN ON LIMITED

CONDITIONS, E.G. TIME, CONTENT,

PAYMENT

CONTENT ENCRYPTIONALGORITHM

DECRYPTIONALGORITHM

CONDITIONAL ACCESS

CONDITIONAL ACCESS CAN BE A CARD GIVENTO THE USER, OR CERTIFICATE SEND VIA INTERNET

• EXAMPLE – THE SYSTEM USED IN DIGITAL TELEVISION FOR

WATCHING PAY PROGRAMS IN THIS SYSTEM CA HAS A FORM OF SUBSCRIPTION CARDS HOWEVER, THERE ARE SEVERAL ENCRYPTION ALGORITHMS USED. FOR DECRYPTION, THERE ARE DIFFERENT HARDWARE CAM’s CONDITIONAL ACCESS MODULES

CAM MODULE SUBSCRIPTION CARD

RECEIVER FOR DIGITAL TELEVISION

• ONE RECEIVER CAN HAVE SEVERAL CAM’s FOR RECEIVING

PAY PACKAGES WITH DIFFERENT SUBSCRIPTION CARDS. SUCH

SYSTEMS ARE WIDELY USED IN TELEVISION.

BUT MANY SYSTEMS WERE ALSO BROKEN SINCE ONE CAN ANALYZE PROGRAM ON THE CARD AND

TRACE TRAFFIC BETWEEN CARD AND CAM.

• BUT WHAT TO DO IF A USER HAS

VALID SUBSCRIPTION BUT USES

IT FOR RECORDING AND DISTRIBUTING CONTENT ILLEGALLY?

ONE SOLUTION IS TO PREVENT

RECORDING AND/OR TO PREVENT

GETTING THE RECORDING OUT

OF THE DEVICE

• IN MEDIA TERMINAL USER CAN

RECORD DIGITAL TV PROGRAMS

ON INTERNAL HARD DISC

• BUT RECORDED CONTENT IS

ENCRYPTED AND THERE IS NO

WAY OF GETTING IT OUT OF THE

TERMINAL

REVOCATION OF RIGHTS

• Revocation means that grants given once

are removed from the user who breached the contract.

We shall explain revocation on the new

example of High Definition DVD discs

a system called Blue Ray

Current DRM systems for DVD

Standard Definition

CSS= Content Scramble System

DVD

Legacy Format Advanced Format

High Definition

AACS= Advanced Access Content System

Blu-ray DiscOther

formats

DVD ContentProtection is broken

HD BR is a new system with muchimproved protection and REVOCATION

Content Scramble System (CSS)Protection for DVD

• A data encryption and authentication scheme to prevent copying video files from the disks

• Several keys included in: authentication key, disc key, player key, title key, second disk key set, and/or encrypted key

• a weak 40-bit stream cipher algorithm• Brute Force Attact, possible to find the keys, only 2^40 options,

attacts to the hash codes

• Published 1996, but only usable in licensed DVD playbacks (Windows, MAC), not in Linux

1999 DeCSS

Advanced Access Content System (AACS) for HD BLUE RAY

• = a standard for content distribution and digital rights management, intended to restrict access to and copying of the next generation of optical discs and DVDs.

• “ a specification for managing content stored on the next generation of prerecorded and recorded optical media for consumer use with PCs and CE devices. “

• “will complement new innovations in the next-generation of optical discs, and enable consumers to enjoy next-generation content, including high-definition content.”

• The specification released in April 2005

AACS – Design criteria• Meet the content owners’ requirements for robustness and system

renewability– Content encryption based on a published cryptographic algorithm.– Limit access to protected content to only licensed compliant

implementations.– Support revocation of individual compromised devices’ keys.

• Suitable for implementation on both general-purpose computer and fixed-function consumer electronics platforms.• Applicable to both audio and video content, including high-definition video.• Applicable to various optical media formats.• Transparent to authorized use by consumers.

• Basic technical elements:- Robust encryption of protected content using the AES cipher.- Key management and revocation using advanced Media Key Block

technology.

AACS - Usage Scenarios

AACS : Content validation and revocation

Content Owner

Content Owner

Licensing Entity

Licenced Player

AACS: System overview – pre-recorded videoCONTENT OWNER

LICENSING ENTITY

LICENCED REPLICATOR

LICENCED PLAYER

ContentUsage rules

Device revocation data [MEDIA KEY BLOCK]Content revocatio list [CRL]Content sertificate

Sequence Key BlockSecret keys

Device keys (unique for the device /application)

Entity public keys (to check the content revocation data and content sertificate)

PRE-RECORDED VIDEOTitle keys - Encrypted content - Usage rules of content

-Content certificate -Content hash-Device revocation data [MKB]-Content revocation list [CRL]-Sequence key block

SERVCE PROVIDER

Enhanced uses enabled via online authentication

AACS: Content encryption and decryption

AACS: Revoking the keys – in practice

In practice the operation of revocation in AACS is as follows:

- Each content (e.g. movie disc) release gets special key-Each type of player (hardware and software) gets special key

Now let’s think that somebody has broken protection of thismovie disc and released illegal copies or has modified player so it can play illegally the content.

Then those discs and players will be put on the revocation list.The list is updated on all new discs, so the when new disc is played on the player, playback of the broken disc will be disabledor the player is disabled!

AACS: Revoking the keys – in practice

• Feb 2007. 128-bit string of keys was published

– Compromises the part of AACS

– Common keys for software players (Cyberlink, Intervideo)

• Revocation started

– HD DVD’s with New Media Block’s on markets in May

Customers not able to play any disks released after may 2007 until the sofware versions are released

- Sofware updates = lots of work, not available yet?

Summary• DMR

= technologies used by publishers or copyright owners to control access to or usage of digital data or hardware, and to restrictions associated with a specific instance of a digital work or device

– to protect high-value digital assets

– control their distribution and usage

• AACS– Cross-industry collaboration to facilitate next generation content distribution

– Enables new, flexible ways to enjoy content while protecting copyrighted works

– Technical specifications and licensing


MPEG – 21Standard


Why MPEG-21• Today many elements exist to build an infrastructure for

delivery and consumption of multimedia content. There is no ”big picture” to describe how these elements relate to each other. The aim of MPEG-21 is to describe how these various elements fit together.

• The result is an open framework with both the content creator and content consumer as focal points.

• The vision of MPEG-21 is to define a framework to enable transparent and augmented use of multimedia resources across a wide range of networks and devices used by different communities.


MPEG-21 – The vision

• A future where every human on the earth is potentially an element of a network involving billions of– content providers– value adders– packagers– service providers– consumers– resellers

• To make this future real we need an infrastructure enabling electronic commerce of digital content


MPEG-21 - Method of work

• Define a framework supporting the vision statement• Involve relevant bodies in this effort• Identify the critical technologies of the framework• Understand how the components of the framework are

related and identify where gaps exist• For each of the non-available technologies

– If they fall under the MPEG expertise then develop them– Else engage other bodies to achieve their development

• Perform the actual integration of the technologies


Is MPEG trying to tame the hackers?

• MPEG technologies have been used to innovate substantially the way people produce, offer, access and consume digital content

• But MPEG has a also long history in working with the creative industries and rights holders’ communities on the identification, management and protection of intellectual property carried on systems designed to MPEG specifications.


The basic elements of the MPEG-21 framework

• What– A Digital Item is a structured digital object with a

standard representation, identification and metadata within the MPEG-21 framework.

• Who– A User is any entity that interacts in the MPEG-21

environment or makes use of a Digital Item.

User A User BTransaction / Use / Relationship

Digital Item Authorization / Value Exchange


Example of Digital Item “music compilation”

• music

• photos

• video

• animation graphics

• lyrics

• scores

• MIDI files

• interview with the singers

• news related to the song

• statement by an opinion maker

• rating of an agency

• position in the hit list

• navigational information driven by user preferences

• bargains

• ...


What Users can do?

Create content Provide content Archive content Rate content Enhance/deliver content Aggregate content Syndicate content

Retail sale of content Consume content Subscribe to content Regulate content Facilitate transactions that

occur from any of the above

Regulate transactions that occur from any of the above


MPEG-21 Multimedia Framework

• Multimedia technology provides the different players in the multimedia value and delivery chain with excess of information and services.

• No complete solutions exist that allow different communities (content, financial, communications, computer and electronics and their customers), each with their own models, rules, procedures, interests and content formats to interact efficientely using this infrastructure.

• The multimedia content delivery chain encompasses content creation, production, delivery and consumption. To support this, the content has to be identified, described, managed and protected.

• The aim of multimedia deliver system is to be interoperable, the transactions to be as simple as possible, and if is possible to be automated.


The seven key elements defined in MPEG-21

1. Digital Item Declaration - a uniform and flexible abstraction and interoperable scheme for declaring Digital Items;

2. Digital Item Identification and Description - a framework for identification and description of any entity regardless of its nature, type or granularity;

3. Content Handling and Usage - provide interfaces and protocols that enable creation, manipulation, search, access, storage, delivery, and (re)use of content across the content distribution and consumption value chain;


The seven key elements defined in MPEG-21

4. Intellectual Property Management and Protection - the means to enable content to be persistently and reliably managed and protected across a wide range of networks and devices;

5. Terminals and Networks - the ability to provide interoperable and transparent access to content across networks and terminals;

6. Content Representation - how the media resources are represented;

7. Event Reporting - the metrics and interfaces that enable Users to understand precisely the performance of all reportable events within the framework;


The MultimediaFramework

Content Management

and Usage

Intellectual Property

Management and Protection

Content Representation

Terminals and Networks

Digital Item Identification

and Description

Digital Item Declaration

Even

t Rep

ortin

g

Metric

s & In

terfaces E

ven

t R

ep

ort

ing

Met

ric

s &

In

terf

ace

s

User A User BTransaction / Use / Relationship

Digital Item Authorization / Value Exchange

Example:”Container” ”Item”

”Resource”

Example:Unique Identifiers

Content DescriptorsExample:

Storage ManagementContent Personalisations

Example:Encription

AuthentificationWatermarking

Example:Resource AbstractionResource Mgt. (QoS)

Example:Natural and Synthetic

Scalability


MPEG-21 Part1:Vision, Technologies and Strategy

A Technical Report has been written to describe the multimedia framework and its architectural elements together with the functional requirements for their specification that was formally approved in September 2001.

The title “Vision, Technologies and Strategy” has been chosen to reflect the fundamental purpose of the Technical Report. This is to:– Define a 'vision' for a multimedia framework to enable transparent and augmented

use of multimedia resources across a wide range of networks and devices to meet the needs of all users

– Achieve the integration of components and standards to facilitate harmonisation of 'technologies' for the creation, management, transport, manipulation, distribution, and consumption of digital items.

– Define a 'strategy' for achieving a multimedia framework by the development of specifications and standards based on well-defined functional requirements through collaboration with other bodies.


Part 2:Digital Item Declaration

The purpose of the Digital Item Declaration (DID) specification is to describe a set of abstract terms and concepts to form a useful model for defining Digital Items.

This model specifically does not define a language in and of itself. Instead, the model helps to provide a common set of abstract concepts and terms that can be used to define such a scheme, or to perform mappings between existing schemes capable of Digital Item Declaration, for comparison purposes.

The DID technology is described in three normative sections:– Model: The Digital Item Declaration Model describes a set of abstract terms and concepts to

form a useful model for defining Digital Items. Within this model, a Digital Item is the digital representation of “a work”, and as such, it is the thing that is acted upon (managed, described, exchanged, collected, etc.) within the model.

– Representation: Normative description of the syntax and semantics of each of the Digital Item Declaration elements, as represented in XML. This section also contains some non-normative examples for illustrative purposes.

– Schema: Normative XML schema comprising the entire grammar of the Digital Item Declaration representation in XML.


The following sections describe the semantic “meaning” of the principle elements of the Digital Item Declaration Model:

1. Container– A container is a structure that allows items and/or containers to be grouped. These groupings of items and/or

containers can be used to form logical packages (for transport or exchange) or logical shelves (for organization). Descriptors allow for the “labelling” of containers with information that is appropriate for the purpose of the grouping (e.g. delivery instructions for a package, or category information for a shelf).

– It should be noted that a container itself is not an item; containers are groupings of items and/or containers.

2. Item– An item is a grouping of sub-items and/or components that are bound to relevant descriptors. Descriptors

contain information about the item, as a representation of a work. Items may contain choices, which allow them to be customized or configured. Items may be conditional (on predicates asserted by selections defined in the choices). An item that contains no sub-items can be considered an entity -- a logically indivisible work. An item that does contain sub-items can be considered a compilation -- a work composed of potentially independent sub-parts. Items may also contain annotations to their sub-parts.

– The relationship between items and Digital Items (as defined in ISO/IEC 21000-1:2001, MPEG-21 Vision, Technologies and Strategy) could be stated as follows: items are declarative representations of Digital Items.

3. Component– A component is the binding of a resource to all of its relevant descriptors. These descriptors are information

related to all or part of the specific resource instance. Such descriptors will typically contain control or structural information about the resource (such as bit rate, character set, start points or encryption information) but not information describing the “content” within.

– It should be noted that a component itself is not an item; components are building blocks of items.



4. Anchor– An anchor binds descriptors to a fragment, which corresponds to a specific location or range

within a resource.5. Descriptor

– A descriptor associates information with the enclosing element. This information may be a component (such as a thumbnail of an image, or a text component), or a textual statement.

6. Condition– A condition describes the enclosing element as being optional, and links it to the selection(s)

that affect its inclusion. Multiple predicates within a condition are combined as a conjunction (an AND relationship). Any predicate can be negated within a condition. Multiple conditions associated with a given element are combined as a disjunction (an OR relationship) when determining whether to include the element.

7. Choice– A choice describes a set of related selections that can affect the configuration of an item. The

selections within a choice are either exclusive (choose exactly one) or inclusive (choose any number, including all or none).



8. Selection– A selection describes a specific decision that will affect one or more conditions somewhere

within an item. If the selection is chosen, its predicate becomes true; if it is not chosen, its predicate becomes false; if it is left unresolved, its predicate is undecided.

9. Annotation– An annotation describes a set of information about another identified element of the model

without altering or adding to that element. The information can take the form of assertions, descriptors, and anchors.

10. Assertion– An assertion defines a full or partially configured state of a choice by asserting true, false or

undecided values for some number of predicates associated with the selections for that choice.11. Resource

– A resource is an individually identifiable asset such as a video or audio clip, an image, or a textual asset. A resource may also potentially be a physical object. All resources must be locatable via an unambiguous address.

12. Fragment– A fragment unambiguously designates a specific point or range within a resource. Fragment

may be resource type specific.



13. Statement– A statement is a literal textual value that contains information, but not an asset. Examples of likely

statements include descriptive, control, revision tracking or identifying information.

14. Predicate– A predicate is an unambiguously identifiable Declaration that can be true, false or undecided.


Example:

Model of Digital Identification Declaration

The figure is an example showing the most important elements within this model, how they are related, and as such, the hierarchical structure of the Digital Item Declaration Model.


Part 3Digital Item Identification and Description

The scope of the Digital Item Identification and Description (DII&D) specification includes:

– How to identify uniquely and describe Digital Items (and parts thereof) and other Entities. – The relationship between Digital Items (and parts thereof) and existing identification systems

contains a list of relevant identification systems. This is not an exhaustive list and is subject to change over time.

– The relationship between Digital Items (and parts thereof) and relevant description schemes contains a list of relevant description schemes. This is not an exhaustive list and is subject to change over time.

Digital Items and their parts within the MPEG-21 Framework are identified by encapsulating Uniform Resource Identifiers into the Identification DS. A Uniform Resource Identifier (URI) is a compact string of characters for identifying an abstract or physical resource, where a resource is defined as "anything that has identity".

The requirement that an MPEG-21 Digital Item Identifier be a URI is also consistent with the statement that the MPEG-21 identifier may be a Uniform Resource Locator (URL). The term URL refers to a specific subset of URI that is in use today as pointers to information on the Internet; it allows for long-term to short-term persistence depending on the business case.


Relationship between Digital Item Declaration and Digital Item Identification & Description


Part 4:Intellectual Property Management and Protection

(IPMP)

• The 4th part of MPEG-21 defines an interoperable framework for Intellectual Property Management and Protection (IPMP).

• The project includes standardized ways of retrieving IPMP tools from remote locations, exchanging messages between IPMP tools and between these tools and the terminal. It also addresses authentication of IPMP tools, and has provisions for integrating Rights Expressions according to the Rights Data Dictionary and the Rights Expression Language.


Part 5:Rights Expression Language (REL)

• Is seen as a machine-readable language that can declare rights and permissions using the terms as defined in the Rights Data Dictionary.

• Is intended to provide flexible, interoperable mechanisms to support transparent and augmented use of digital resources in publishing, distributing, and consuming of electronic books, broadcasting, digital movies, digital music, interactive games, computer software and other creations in digital form, in a way that protects digital content and honours the rights, conditions, and fees specified for digital contents. It is also intended to support specification of access and use controls for digital content in cases where financial exchange is not part of the terms of use, and to support exchange of sensitive or private digital content.

• Is intended to provide flexible interoperable mechanism to ensure personal data is processed in accordance with individual rights and to meet the requirement for Users to be able to express their rights and interests in a way that addresses issues of privacy and use of personal data.

• A standard REL should be able to support guaranteed end-to-end interoperability, consistency and reliability between different systems and services. To do so, it must offer richness and extensibility in declaring rights, conditions and obligations, ease and persistence in identifying and associating these with digital contents, and flexibility in supporting multiple usage/business models.


Part 6:Rights Data Dictionary (RDD)

1. RDD provides a set of clear, consistent, structured and integrated definitions of terms for use in the MPEG-21 Rights Expression Language.

2. Terms in RDD are categorized as Primitive, Native, Adopted and Mapped. The definitions of Primitive and Native terms are determined by the governance process of the RDD. Definitions of Adopted and Mapped terms are determined externally.

3. RDD is a semantic network through which the definitions of terms are developed through the medium of its primary data model (the Context Model) supported by two secondary models (the Resource Model and the Ascriptive Model).

4. RDD terms are drawn from a continually-expanding and diverse range of governed descriptive, legal and commercial metadata systems and schemes, supporting the description of rights and permissions in Digital Items, physical objects and abstract entities, incorporated within MPEG standards as well as those defined and governed elsewhere.

5. Terms will be added to the RDD or modified in accordance with its declared governance process.6. RDD supports interoperability, so that metadata necessary for the management of rights and

permissions can cross in and out of domains in an automated or partially-automated way with the minimum ambiguity or loss of semantic integrity.

7. Primitive, Native and Adopted terms within RDD do not define intellectual property rights or other legal entities. RDD Primitive, Native and Adopted terminology implies no assumptions about the nature or extent of specific legal rights, the commerce (or other) models through which rights may be exploited or protected, or the legal frameworks within which they operate.

8. RDD includes the terms from all metadata schemes and systems which have been mapped to it.


Part 7:Digital Item Adaptation

• The goal of the Terminals and Networks key element is to achieve interoperable transparent access to (distributed) advanced multimedia content by shielding users from network and terminal installation, management and implementation issues. This will enable the provision of network and terminal resources on demand to form user communities where multimedia content can be created and shared, always with the agreed / contracted quality, reliability and flexibility, allowing the multimedia applications to connect diverse sets of Users, such that the quality of the user experience will be guaranteed.

MPEG-21 Summary

• Provides standardized and comprehensive

framework for dealing with digital content,

practically for any purpose

• It is not used (yet?) because commercial interests until now promote closed proprietary solutions (example: mobile shops for content)
