The use of P2P networks for multimedia distribution has spread out globally in recent years. Therefore, there is a strong need for a content distribution mechanism over P2P networks that do not pose security and privacy threats to the copyright holders or to end users, respectively. The existent systems for copyright and privacy protection employ cryptographic mechanisms at a cost of high computational burden which makes these systems impractical for distributing large files. In this presentation, the authors (Amna Qureshi, David Megías, Helena Rifà-Pous) propose and analyse a P2P content distribution system which allows efficient distribution of large-sized content while preserving the security and privacy of merchants and buyers, respectively. The experimental results confirm that the framework provides an efficient solution to copyright infringement issues over P2P networks, while protecting the end users’ privacy.

1. Framework for Preserving Security
and Privacy in Peer-to-Peer
Content Distribution Systems
Amna Qureshi, David Megías and Helena Rifà-Pous
KISON-IN3
1
11th February, 2015UOC Research Showcase
Framework for Preserving Security and Privacy in Peer-to-Peer Content Distribution
Systems

2. • Introduction
• State-of-the-Art
• Secure and Privacy-Preserving Content Distribution Framework
• Experimental and Simulation Results
• Conclusions and Future Work
Outline
2
Framework for Preserving Security and Privacy in Peer-to-Peer Content Distribution
Systems

3. • Multimedia producers
o Protection of copyright
3
Introduction
Content Protection
Framework for Preserving Security and Privacy in Peer-to-Peer Content Distribution
Systems
• End users
o Protection of user-related information
Privacy Protection

4. Introduction
4
Framework for Preserving Security and Privacy in Peer-to-Peer Content Distribution
Systems
Copyright Infringement in P2P Content Distribution Systems

5. • Conflict between content providers and end users:
o Reconciliation of user privacy with content protection.
• Trade-off between watermarking properies:
o Robustness, transparency and capacity.
• Harmonization between accountability and anonymity:
o Revocable privacy for an end user.
• Merging collusion-resistant fingerprinting and secure embedding scheme.
• Computational and distribution efficiency:
o Low computational and communicational burdens for the content providers and the end
users.
5
Introduction
Framework for Preserving Security and Privacy in Peer-to-Peer Content Distribution
Systems
Research Challenges

6. 6
State-of-the-Art
Security Properties for Content Providers
Framework for Preserving Security and Privacy in Peer-to-Peer Content Distribution
Systems
Copyright
protection
Data
privacy
Traceablity
Data
integrity
Copy
prevention
Resistance
against
attacks
User privacy
Protection of real
identity
Unlinkability
Resistance
against de-
anonymization
attacks
Data privacy
Available to
authorized users
only
Protection
against
malicious
attacks
Privacy Properties for End users

7. 7
State-of-the-Art
Framework for Preserving Security and Privacy in Peer-to-Peer Content Distribution
Systems
P2P
Systems
Content
Protection
Privacy
Protection
Revocable
PrivacyCopyright
Protection
Traceability User Data
Megías
(2014)
Yes Yes Yes Yes Yes
Megías & Domingo-Ferrer
(2014)
Yes Yes Yes Yes Yes
Domingo-Ferrer & Megías
(2013)
Yes Yes Yes Yes Yes
P2P
Systems
Robustness and Security against Attacks
Signal
Processing
Attacks
Collusion Attacks
Communication
AttacksContent Protection
Systems
Privacy
Protection
Systems
Megías
(2014)
Yes Yes Yes Yes
Megías & Domingo-Ferrer
(2014)
Yes Yes Yes Yes
Comparative Analysis of Secure and Privacy-Preserving P2P Content Distribution Systems

8. 8
Security and Privacy-Preserving Content
Distribution Framework
Overview of the Framework
Framework for Preserving Security and Privacy in Peer-to-Peer Content Distribution
Systems
P2P
network
Trust
infrastructures
Building
blocks
Hybrid P2P Public key support Embedding domain
Trusted third
parties with limited
services
Embedding algorithm
Collusion-resistant
fingerprinting codes
Public key
cryptosystem
PseudoTrust model

9. 9
Security and Privacy-Preserving Content
Distribution Framework
Overview of the Framework
Framework for Preserving Security and Privacy in Peer-to-Peer Content Distribution
Systems
Parties
involved
Merchant
General
assumptions
Security
assumptions
Assumptions
Design
requirements
Threat
model
Buyer
Super peer
Monitor
Judge
Certification
authority
Security
requirements
Privacy
requirements
Watermarking
attacks
Collusion attacks
Framing attacks
Communication
attacks

10. 10
Protocols of the Framework
File Partitioning Protocol
Framework for Preserving Security and Privacy in Peer-to-Peer Content Distribution
Systems
Merchant Multimedia
content
DWT
Transform
Approximation coefficients
Detail coefficients
Monitor
Fingerprint
generation
Embed fingerprint into
approximation coefficients
Base file
Supplementary file

11. 11
Protocols of the Framework
Base File Distribution Protocol
Framework for Preserving Security and Privacy in Peer-to-Peer Content Distribution
Systems
9. Buyer decrypts
EK*pBi(BF) using
secret key
Merchant
Monitor
Buyer
4. fi Generation
5. fi Encryption with K*pBi
7. Embedding EK*pBi (f)
into EK*pBi (X)
EK*pBi (X)
EKpB(X)EKpB(f) => EK*pBi(BF)
EK*pBi (f)
10. Fingerprinted BF

12. 12
Protocols of the Framework
Supplementary File Distribution Protocol
Framework for Preserving Security and Privacy in Peer-to-Peer Content Distribution
Systems
Merchant
Certification
Authority
P2P Network
Pseudonyms
and
signed
certificate
acquisation

13. 13
Protocols of the Framework
Traitor-Tracing and Dispute Resolution Protocol
Framework for Preserving Security and Privacy in Peer-to-Peer Content Distribution
Systems
Merchant
Monitor
Judge
Certification
Authority
Multimedia
content
Collusion
attack
Set of
colluders

14. 14
Security and Privacy-Preserving Content
Distribution Framework
Security Analysis of BF Distribution Protocol
Framework for Preserving Security and Privacy in Peer-to-Peer Content Distribution
Systems
• Buyer frameproofness
• Non-repudiation
• Revocable privacy
• Anonymity
• Traceability
• Collusion resistance
• Unlinkability
Security Analysis of SF Distribution Protocol
• Impersonation
• Man-in-the-middle attack
• Replay attack
• Leakage of a secret number
used in pseudo-idenity
generation

15. 15
Security and Privacy-Preserving Content
Distribution Framework
Security against Collusion Attacks
Framework for Preserving Security and Privacy in Peer-to-Peer Content Distribution
Systems
No. of
Colluders
No. of Colluders Detected for Attacks in the
Framework for a Video File
U Average Minimum Maximum Median
2 2 2 2 2
3 3 3 3 3
4 4 4 4 4
5 5 4 4 5

16. 16
Experimental and Simulation Results
Details of Audio Files
Framework for Preserving Security and Privacy in Peer-to-Peer Content Distribution
Systems
Loopy
Music
Huge
wav
Aasan
Nai
Yahan
Duration
(min:secs)
00:10 00:17 03:34
Original Size
(MB)
0.89 2.97 36.01
Base File
Size (MB)
0.52 0.88 9.80
Supplement-
ary File Size
(MB)
1.79 5.94 72.16
ODG Value -0.48 -0.98 -1.20
Details of Video Files
Traffic Dragon Breaking
Bad
Duration
(min:secs)
00:10 23:00 50:00
Original Size
(MB)
0.19 51.10 305.00
Base File
Size (MB)
0.08 9.21 11.80
Supplement-
ary File Size
(MB)
0.18 69.40 216.00
PSNR Value
(dB)
44.00 42.00 41.00

17. 17
Experimental and Simulation Results
Robusntess of an Audio File
Framework for Preserving Security and Privacy in Peer-to-Peer Content Distribution
Systems
Robustness of a Video File
Attacks Parameters BER NC
Re-
quantization
16-8-16
bits
0.07 0.951
Re-sampling
44.1-22.05-
44.1 KHz
0.11 0.902
MP3
Compression
256 kbps 0.09 0.912
AWGN 18 dB 0.13 0.882
Attacks Parameters BER NC
Median
filter
[3 x 3] 0.09 0.912
Re-sizing
320-640-320
pixels
0.06 0.972
H.264
Compression
768 kbps 0.09 0.912
AWGN 20 dB 0.14 0.856

18. 18
Experimental and Simulation Results
Computational Time of Audio Files
Framework for Preserving Security and Privacy in Peer-to-Peer Content Distribution
Systems
Computational Time of Video Files
CPU Time in secs
Process Loopy
Music
Huge
Wav
Aasan
Nai
Yahan
Fingerprint
generation
6.01 6.01 6.01
Base file
generation
14.08 31.15 181.39
Supplementary
file
generation
0.03 0.18 1.19
Total time 20.13 37.34 188.60
CPU Time in secs
Process Traffic Dragon Breaking
Bad
Fingerprint
generation
6.01 6.01 6.01
Base file
generation
14.08 31.15 181.39
Supplementary
file
generation
0.03 0.18 1.19
Total time 20.13 37.34 188.60

19. 19
Experimental and Simulation Results
CommunicationTime of an Audio File
Framework for Preserving Security and Privacy in Peer-to-Peer Content Distribution
Systems
Communication Time of a Video File
Communication time in secs
File
name
BF
delivery
SF
delivery
File
Recon-
struction
Total
time
Loopy
Music
8.01 10.00 3.89 21.90
Communication time in secs
File
name
BF
delivery
SF
delivery
File
Recon-
struction
Total
time
Break-
ing Bad
184.00 657.29 595.05 1436.34
Cryptographic Algorithms
CPU time in
secs
Public-key cryptography 5.73
Anonymous key exchange 9.62
AES encryption/decryption 1.89
Total 17.24
Cryptographic Costs of an Audio File Cryptographic Costs of a Video File
Cryptographic Algorithms
CPU time in
secs
Public-key cryptography 8.80
Anonymous key exchange 9.62
AES encryption/decryption 0.11
Total 18.53

20. 20
Conclusions and Future Work
Conclusions
Future Work
• A P2P content distribution system which allows efficient distribution of large-sized
content while preserving the security and privacy of content providers and end
users.
• The security and performance analysis demonstrates the security and efficiency
of the proposed framework.
• The framework is able to resolve the problems of piracy tracing, buyer
frameproofness, collusion resistance, accountability, dispute resolution and
buyer’s privacy.
• Reduce the size of the base file through losless compression techniques.
• Develop a prototype of the proposed framework and test it in a real-world scenario.
Framework for Preserving Security and Privacy in Peer-to-Peer Content Distribution
Systems

21. 21
Thank you!
Framework for Preserving Security and Privacy in Peer-to-Peer Content Distribution
Systems