MULTIMEDIA SERVERS,
DRM and the
MPEG-21 Standard
MULTIMEDIA SYSTEMS
IREK DEFEE
• 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
MULTIMEDIA SYSTEMS
IREK DEFEE
• 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
MULTIMEDIA SYSTEMS
IREK DEFEE
• 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 SYSTEMS
IREK DEFEE
• 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?
MULTIMEDIA SYSTEMS
IREK DEFEE
• 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
MULTIMEDIA SYSTEMS
IREK DEFEE
• 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
MULTIMEDIA SYSTEMS
IREK DEFEE
CONSTRUCTION OF HARD DISC:
MAGNETIC MATERIAL ON PLATTERS IS ARRANGED
IN TRACKS.
HEADS ARE READING/WRITING BY CHANGING
MAGNETIC ORIENTATION
MULTIMEDIA SYSTEMS
IREK DEFEE
• 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
MULTIMEDIA SYSTEMS
IREK DEFEE
• 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
MULTIMEDIA SYSTEMS
IREK DEFEE
• 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
MULTIMEDIA SYSTEMS
IREK DEFEE
• 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
MULTIMEDIA SYSTEMS
IREK DEFEE
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 START
READING, THE SPEED CAN BE E.G. 100 MB/S
FOR STREAMS, ONE HAS TO READ AS MANY
HIGH BANDWIDTH STREAMS AS POSSIBLE.
E.G. 180 STREAMS WITH 3 Mb/s EACH
MULTIMEDIA SYSTEMS
IREK DEFEE
IN PRACTICE THERE WILL BE MANY
PARAMETERS IN THE DESIGN OF MEDIA SERVER
-MEMORY BUFFERS
-NETWORK INTERFACES
-OPERATING SYSTEM
THEY 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
MULTIMEDIA SYSTEMS
IREK DEFEE
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
MULTIMEDIA SYSTEMS
IREK DEFEE
THUS, THE MEDIA SERVER PERFORMANCE
MIGHT BE LIMITED BY VARIOUS
COMPONENTS 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 SYSTEM
BUT THIS SHOULD NOT BE A PROBLEM
THE QUESTION IS: HOW TO INCREASE THE
HARD DISC STORAGE SPEED?
MULTIMEDIA SYSTEMS
IREK DEFEE
HERE WE SEE STANDARD COMPUTER ARCHITECTURE
IT COULD BE A PC WITH SATA HARD DISC
DEVICE INTERFACE PLUS PROCESSOR
IF WE CONNECT MORE DISCS, THIS WILL INCREASE
STORAGE SIZE BUT NOT ITS SPEED
WE NEED TO USE SOMETHING ELSE AND THIS IS... RAID ->
MULTIMEDIA SYSTEMS
IREK DEFEE
STRIPING AND RAID
• A METHOD FOR INCREASING
STORAGE AND OUTPUT CAPACITY
IS BY CONNECTING HARD DISCS IN
PARALLEL AND STRIPING FILES
ON THEM
MULTIMEDIA SYSTEMS
IREK DEFEE
STRIPING AND RAID
F
I
L
E
DISC
SYSTEM
S
T
R
I
P
I
N
G
DISC
CONTROLLER
DISC
THREE DISCS = THREE TIMES HIGHER OUTPUT
MULTIMEDIA SYSTEMS
IREK DEFEE
• 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 N
TIMES HIGHER OUTPUT CAPACITY
AND N TIMES BIGGER STORAGE
MULTIMEDIA SYSTEMS
IREK DEFEE
STRIPING PRINCIPLE
BLOCKS OF DATA ARE STRIPED
AMONG DIFFERENT DISCS
OPERATING IN PARALLEL
IN THIS WAY SPEED OF READING
AND WRITING CAN BE INCREASED
MULTIMEDIA SYSTEMS
IREK DEFEE
• 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
MULTIMEDIA SYSTEMS
IREK DEFEE
F
I
L
E
S
T
R
I
P
I
N
G
ERROR
CORRECT.
DISC
PARITY
DISC
RAID
ADDED DISCS FOR
ERROR CONTROL
DISC
SYSTEM
DISC
CONTROLLER
DISC
MULTIMEDIA SYSTEMS
IREK DEFEE
• 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
MULTIMEDIA SYSTEMS
IREK DEFEE
• 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
MULTIMEDIA SYSTEMS
IREK DEFEE
OVERALL ARCHITECTURE OF MACHINE
WITH RAID DISC ARRAY AND NETWORK
ADAPTERS
RAID CAN BE IMPLEMENTED IN SOFTWARE
OR IN HARDWARE
HARDWARE RAID WILL PUT LESS LOAD
ON THE PROCESSOR AND SYSTEM
MULTIMEDIA SYSTEMS
IREK DEFEE
• DISC ARRAYS CAN BE BUILT WITH
TENS OF TERABYTES.
THUS ENOUGH STORAGE CAPACITY
EXISTS FOR STORING VERY LARGE
COLLECTIONS OF MULTIMEDIA
DATA
MULTIMEDIA SYSTEMS
IREK DEFEE
• 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
MULTIMEDIA SYSTEMS
IREK DEFEE
• 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
MULTIMEDIA SYSTEMS
IREK DEFEE
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
MULTIMEDIA SYSTEMS
IREK DEFEE
• SOMETIMES WE CAN APPLY
MULTICASTING IN WHICH MANY
USERS GET THE SAME STREAM –
ONLY A SINGLE STREAM IS
RETRIEVED FROM HARD
DISC SOMETIMES APPLICABLE
MULTIMEDIA SYSTEMS
IREK DEFEE
• 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)
MULTIMEDIA SYSTEMS
IREK DEFEE
MEDIA SERVER DESIGN:
RAID STORAGE
STORAGE BUS
E.G. SATA III
PCIe
BUS
P...
...P
PROCESSOR(S)
RAM BUFFERS
NETWORK INTERFACE
WITH BUFFER
DATA FROM STORAGE ARE TRANSFERRED
TO RAM BUFFERS AND THEN TO NETWORK
INTERFACE
THE BIGGER THE RAM BUFFER, THE MORE
STREAMS COULD BE SUPPORTED BY THE
SERVER BUT IT WILL TAKE MORE TIME TO
FILL THE BUFFER SO THE START OF
CONTENT WOULD BE DELAYED.
THUS RAM BUFFERS CAN NOT BE TOO
BIG IN PRINCIPLE.
BUT ONE CAN TRY TO OPTIMIZE THE
SYSTEM CREATING BIGGER BUFFERS
WHEN SYSTEM IS NOT LOADED MUCH
AND SHORTER BUFFERS WHEN THERE
IS HIGH LOAD.
OVERALL SERVER OPTIMIZATION MIGHT
BE STILL AN OPEN PROBLEM
(OR COMERCIAL SECRETS ARE HERE?)
MULTIMEDIA SYSTEMS
IREK DEFEE
ONE IDEA IS TO DESIGN SPECIAL BIG
MACHINE WITH VERY MANY BUSES,
PROCESSORS, AND CONNECTED TO
BROADBAND NETWORK, WE SHOULD
TAKE INTO ACCOUNT THAT NETWORK
BANDWIDTH FROM COMPUTERS IS
LIMITED, E.G. GIGABIT ETHERNET IS
FASTEST PRACTICAL INTERFACE TODAY,
1000 Mb/s THOUGH SEVERAL SUCH INTERFACES
CAN BE USED AND THERE IS ALSO 10 Gb/s
INTERFACE
THUS, A BIG MACHINE WOULD NEED
TO HAVE MULTIPLE NETWORK INTERFACES
IT WOULD BE VERY EXPENSIVE
MULTIMEDIA SYSTEMS
IREK DEFEE
• SUCH DEDICATED MACHINES
WOULD REQUIRE:
- MULTIPROCESSING
- MULTIPLE I/O TO THE NETWORK
- VERY BIG DISTRIBUTED STORAGE
MACHINE WOULD BE VERY EXPENSIVE
AND NON-STANDARD
MULTIMEDIA SYSTEMS
IREK DEFEE
• 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
MULTIMEDIA SYSTEMS
IREK DEFEE
• DEDICATED MACHINES
- MULTIPROCESSING
- MULTIPLE I/O
- DISTRIBUTED STORAGE
EXPENSIVE AND NON-STANDARD
MULTIMEDIA SYSTEMS
IREK DEFEE
•ANOTHER IDEA: MULTIPLE STANDARD
MACHINES. MEDIA FILES ARE DISTRIBUTED
ALONG A NUMBER OF SERVERS WHICH
HAVE COMMON CONTROL
HERE THE PROBLEM IS THAT STORAGE
REQUIRED MIGHT BE BIGGER (OFTEN USED
MEDIA STREAMS ON MANY SERVERS
MULTIMEDIA SYSTEMS
IREK DEFEE
• 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
MULTIMEDIA SYSTEMS
IREK DEFEE
BASIC IDEA
FOR MANY
SIMPLE SERVERS
HOWEVER, THEN EACH SERVER WOULD
NEED TO HAVE STORAGE WITH ALL MEDIA
FILES, SO OVERALL THERE WOULD BE
MUCH MORE STORAGE NEEDED THAN IN
A SINGLE BIG SERVER
MULTIMEDIA SYSTEMS
IREK DEFEE
ANOTHER CONCEPT – MULTIPLE SERVERS
CONNECTED VIA NETWORK. THE NETWORK
CAN BE UED FOR FILE TRANSFER BETWEEN
SERVERS. STORAGE CAN BE ADAPTED FOR
THE DEMAND (ONLY POPULAR STREAMS WOULD
BE ON MORE SERVERS, SAVING STORAGE)
MULTIMEDIA SYSTEMS
IREK DEFEE
YET ANOTHER SYSTEM: STORAGE AND
SERVERS ARE SEPARATED, THEN SERVERS
WILL BUFFER AND REPLICATE STREAMS
WHICH ARE IN DEMAND
MULTIMEDIA SYSTEMS
IREK DEFEE
• 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
MULTIMEDIA SYSTEMS
IREK DEFEE
IN FACT MEDIA SERVER IS MUCH MORE THAN
JUST SENDING STREAMS: USERS WILL
CONNECT/DISCONNECT, SEARCH APPLICATIONS
-ALL THIS NEEDS TO BE MANAGED.
THERE WILL BE MANY CONTROL FLOWS
MULTIMEDIA SYSTEMS
IREK DEFEE
THE SYSTEMS WILL OFTEN REQUIRE PAYING,
THUS EXTENSIVE DATABASE OF USERS,
PAYMENTS, BILLING, AUTHORIZATION,
AUTHENTICATION WILL BE NEEDED.
ENCRYPTION OF DATA WILL BE NECESSARY
MULTIMEDIA SYSTEMS
IREK DEFEE
IF USERS HAVE ACCESS TO BROADBAND
NETWORK OTHER APPLICATIONS MIGHT
BE ATTRACTIVE: WEB ACCESS, OWN BROADCAST,
VIDEOTELEPHONE, VIDEO CONFERENCING
MULTIMEDIA SYSTEMS
IREK DEFEE
ON THE OPERATOR SIDE, FULL ADMINISTRATION
IS NEEDED:
-SYSTEM OPERATION MONITORING
-ADMISSION CONTROL (NEW USERS)
-CONTENT UPDATES
MULTIMEDIA SYSTEMS
IREK DEFEE
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
MULTIMEDIA SYSTEMS
IREK DEFEE
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 the
network means that the
content has to be protected
against 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
ENCRYPTION
ALGORITHM
DECRYPTION
ALGORITHM
CONTENT
• BUT SUCH SYSTEM HAS PROBLEMS
1. IF ALGORITHM IS KNOWN,
EVERYBODY WILL USE IT
2. 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
CONDITIONAL ACCESS
CONTENT
ENCRYPTION
ALGORITHM
DECRYPTION
ALGORITHM
CONDITIONAL ACCESS CAN BE A CARD GIVEN
TO 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
RECEIVER FOR DIGITAL TELEVISION
CAM MODULE
SUBSCRIPTION CARD
• 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
Legacy Format
Standard Definition
CSS
= Content Scramble System
DVD
Advanced Format
High Definition
AACS
= Advanced Access Content System
Blu-ray Disc
Other
formats
DVD Content HD BR is a new system with much
Protection is improved protection and
broken
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 fixedfunction 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
Licenced Player
Content Owner
Licensing Entity
AACS: System overview – pre-recorded video
CONTENT OWNER
SERVCE PROVIDER
Content
Usage rules
LICENCED REPLICATOR
Device revocation data
[MEDIA KEY BLOCK]
Content revocatio list [CRL]
Content sertificate
PRE-RECORDED VIDEO
Title keys
- Encrypted content
- Usage rules of content
Enhanced uses enabled via
online authentication
LICENCED PLAYER
-Content certificate
-Content hash
-Device revocation data [MKB]
-Content revocation list [CRL]
-Sequence key block
Device keys
(unique for the device /application)
Entity public keys
Sequence Key Block
Secret keys
(to check the content revocation data
and content sertificate)
LICENSING ENTITY
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 this
movie 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 disabled
or 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 – 21
Standard
MULTIMEDIA SYSTEMS
IREK DEFEE
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.
MULTIMEDIA SYSTEMS
IREK DEFEE
MPEG-21 – The vision
• A future where every human on the earth is
potentially an element of a network involving
billions of
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content providers
value adders
packagers
service providers
consumers
resellers
• To make this future real we need an infrastructure
enabling electronic commerce of digital content
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MPEG-21 - Method of work
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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
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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.
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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
Transaction / Use / Relationship
 Digital Item 
 Authorization / Value Exchange 
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User B
Example of Digital Item
“music compilation”
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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
• ...
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What Users can do?

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Create content
Provide content
Archive content
Rate content
Enhance/deliver content
Aggregate content
Syndicate content
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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
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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.
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The seven key elements defined
in MPEG-21
1.
2.
3.
Digital Item Declaration - a uniform and flexible
abstraction and interoperable scheme for declaring
Digital Items;
Digital Item Identification and Description - a
framework for identification and description of any
entity regardless of its nature, type or granularity;
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;
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The seven key elements defined
in MPEG-21
4.
5.
6.
7.
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;
Terminals and Networks - the ability to provide
interoperable and transparent access to content across
networks and terminals;
Content Representation - how the media resources are
represented;
Event Reporting - the metrics and interfaces that enable
Users to understand precisely the performance of all
reportable events within the framework;
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Example:
”Container” ”Item”
”Resource”
Metrics & Interfaces
Example:
Encription
Authentification
Watermarking
Example:
Unique Identifiers
Content Descriptors
Transaction / Use / Relationship
 Digital Item 
 Authorization / Value Exchange 
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Event Reporting
User A
Event Reporting
Example:
Storage Management
Content Personalisations
Metrics & Interfaces
The MultimediaFramework
User B
Example:
Resource Abstraction
Resource 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.
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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.
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The following sections describe the semantic “meaning” of
the principle elements of the Digital Item Declaration Model:
1. Container
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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
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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
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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.
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The following sections describe the semantic “meaning” of
the principle elements of the Digital Item Declaration Model:
4. Anchor
–
An anchor binds descriptors to a fragment, which corresponds to a specific location or range
within a resource.
5. Descriptor
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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
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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).
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The following sections describe the semantic “meaning” of
the principle elements of the Digital Item Declaration Model:
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.
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The following sections describe the semantic “meaning” of
the principle elements of the Digital Item Declaration Model:
13.
Statement
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14.
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.
Predicate
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A predicate is an unambiguously identifiable Declaration that can be true, false or undecided.
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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.
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Part 3
Digital 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.
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Relationship between Digital Item Declaration and Digital
Item Identification & Description
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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.
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•
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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.
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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.
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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.
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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)
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