Content security
Ecole d’été RESCOM 2006
DIEHL
Eric
Technology, Corporate Research, Security Domain Manager
12 June 2006
What is content security about?
Mitigate
Identify
Protect
theft of
source
content
leakage
Eight laws to rule
I
II
III
IV
V
VI
VII
VIII
Law 1: Pirates will always find a way

Examples
– DeCSS unprotected DVD since 1999
– Sony Key2Audio and the lethal pen
– Pay TV cards have always been broken

Design with mandatory renewability
– Smart card

Find the hole
– Track illegal activity
– Watermark
CP
Law 2: Know the assets to protect

Examples
– Wrong asset
– Useless protection

Threat analysis
– What to protect
– Who are the attackers
– Identify the attacks, the consequences and the risk
Law 3: No security through obscurity

Example
– Walmart’s cart
– Selection process of AES
Sound cryptography
 Kerckoff’s law

– Security should rely on the secrecy of keys and not
on secrecy of algorithms
Law 4: Trust no one

Example
– ATT report
 2/3

of content leakage done by insiders!
Simplify the trust model
– The less you need to trust, the more secure you are
BYERS S., et al., Analysis of security vulnerabilities in the movie production and distribution
process, ATT Labs, September 2003 available at http://lorrie.cranor.org/pubs/drm03.html
Law 5: Si vis pacem, para bellum

Example
– DirecTV counter attacks
If you want peace,
prepare war
Know your enemy
 Change the target
 Multiple defenses

– Combination of encryption and watermark
– Physical security and encryption
Law 6: You are the weakest link

Examples:
– Password jeopardy
– Phishing

Social Engineering
–

MITNICK K., The art of deception, WILEY, 2002
Security must be transparent
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Law 7: Security is not stronger than the
weakest link

Example
– High robustness security locks on a thin wooden
door
– Constant failure of Copy Protection for CD-A
– Side Channel Attacks
Design of security from the start
 Strengthen the weakest element

Law 8: Security is a process, not a
product

Examples
– Day-to-day patching process
– Best firewall with default admin password

Security is global
– Secure system A + secure system B is not a secure
system
Security policy is mandatory
 Certainty is a weakness

An example: NexGuard™
Encrypt
content
Decrypt &
watermark
content
Create &
encrypt
licence
Decrypt
licence
An example: NexGuard

Si vis pacem, para bellum
– Encryption, and watermark
– Possible revocation of every element

You are the weakest link
– Transparent for user

No security through obscurity
– Use of proven cryptography (AES, RSA)
– Keys are stored in secure cards

Trust no one
– A very limited set of assumptions
An example: NexGuard

Pirates will always find a way
– Smart card allows renewability

Know the assets to protect
– Only protect content

Security is not stronger than the weakest link
– Special effort in the design of the product

Security is a process, not a product
– Help the customer to design its security policy
 Best
practices, guidelines, …
Conclusions

Piracy is a reality

BUT

A toolbox already exists

Many fields open for academic/industrial research
– Cryptography
– Watermark
– Fingerprint
– Smart cards
– Policy enforcement and definition
– Formal proof of security
–
…
Thank you for your attention
This document is for background informational purposes only. Some points
may, for example, be simplified. No guarantees, implied or otherwise, are
intended