KIANOOSH MOKHTARIAN SCHOOL OF COMPUTING SCIENCE SIMON FRASER UNIVERSITY 3/24/2008 Secure Multimedia Streaming.

KIANOOSH MOKHTARIAN

SCHOOL OF COMPUTING SCIENCESIMON FRASER UNIVERSITY

3/24/2008

Secure Multimedia Streaming

Motivation

Multimedia streaming: a great source of revenue Its market will grow from $900 mln in 2005 to $6 bln in 2011

Motivation


Affecting our daily lives

Motivation


Affecting our daily lives

Security of multimedia systems

Overview

Desired security aspects

Conventional authentication methods

Requirements for a media authentication scheme

Previous works Stream authentication Typical video authentication Scalable video authentication

Conclusion and future research directions

What Security Aspects?


Authentication

Data integrity

Access control

Data confidentiality

Non-repudiation

Availability of service


Authentication

Data integrity

Access control

Data confidentiality

Non-repudiation

Availability of service

An Example

The Olympic games $$!

An Example

The Olympic games

The network is by default UNSECURE Anyone can listen, capture, and replace the traffic.

Conventional Authentication: Preliminaries

Digital signature Publicly verifiable Message dependant Not repudiatable

Conventional Authentication: Preliminaries

Digital signature Publicly verifiable Message dependant Not repudiatable

One-way hash functions Fixed length output Easy to compute y = H(x) for everyone Infeasible to compute x given the value of H(x) Infeasible to find x1 and x2 such that H(x1) = H(x2)

if H(x) is authentic, then x is authentic

Conventional Auth’: the Case of Multimedia

Treating the entire media as a file:Sign ( Hash(media) ) and Verify ( Hash(media) )


Treating the entire media as a file:Sign ( Hash(media) ) and Verify ( Hash(media) ) Cannot produce the media online Cannot verify the media online Sensitive to any loss or adaptation on the media


Treating the entire media as a file:Sign ( Hash(media) ) and Verify ( Hash(media) ) Cannot produce the media online Cannot verify the media online Sensitive to any loss or adaptation

Signing each frame



Signing each frame Computationally expensive




Using Message Authentication Codes (MAC) y = MACK (x) = Hash (x || K)




Using Message Authentication Codes (MAC) y = MACK (x) = Hash (x || K) Cannot go beyond single-sender single-receiver case

Requirements

Requirements

Security!

Requirements

Security!Online production, online verification

Requirements

Security!Online production, online verificationComputational cost

Requirements

Security!Online production, online verificationComputational costCommunication overhead

Requirements

Security!Online production, online verificationComputational costCommunication overheadBuffer needed for authentication purposes

Requirements

Security!Online production, online verificationComputational costCommunication overheadBuffer needed for authentication purposesRobustness against adaptations on the media

Whether to get the proxies involved or not

Requirements


Whether to get the proxies involved or notTolerability of packet losses in network

Requirements


Whether to get the proxies involved or notTolerability of packet losses in networkSupported scenarios

Stream Authentication

Hash chaining

Packet 2 Packet nDigital Signature

Hash

H(pkt3)

Packet 1

H(pkt2)

StreamSignature


Hash chaining

No online production of the authenticated stream


Hash

H(pkt3)

Packet 1

H(pkt2)

StreamSignature


Hash chaining

No online production of the authenticated stream Sensitive to any packet loss


Hash

H(pkt3)

Packet 1

H(pkt2)

StreamSignature


One-time signature Based on conventional (symmetric) cryptographic functions

One-time signature chaining

Packet nDigital

SignatureOne-time signature

Packet 1

Signature on pkt n

StreamSignature

Public key to verify pkt 2

Packet 2

Signature on pkt 2





High communication overhead

Packet nDigital


Packet 1

Signature on pkt n

StreamSignature


Packet 2

Signature on pkt 2





High communication overhead Sensitive to any packet loss

Packet nDigital


Packet 1

Signature on pkt n

StreamSignature


Packet 2

Signature on pkt 2



SAIDA: Signature Amortization using IDA (Information Dispersal Algorithms)

Hash

IDA coding

Packet m

Partial auth info

Packet 2

Partial auth info

Packet 1

Partial auth info

HashHash

Digital Signature


SAIDA: Signature Amortization using IDA (Information Dispersal Algorithms)

Tradeoff between verification delay and overheads

Hash

IDA coding

Packet m

Partial auth info

Packet 2

Partial auth info

Packet 1

Partial auth info

HashHash

Digital Signature

Video Authentication: The General Case

Exploiting the strong correlation between consecutive video frames To reduce overheads To increase robustness

Extract key frames in a video sequence Extract and authenticate key features of such frames Authenticate non-key frames based on key frames

Scalable Video Authentication: Recall

Scalable video To support heterogeneous receivers A base layer and a number of enhancement layers

Base layer

Enhancement layer 1

Enhancement layer 2

Enhancement layer 3

Enhancement layer 4

Frame 1

Base layer

Enhancement layer 1

Enhancement layer 2

Enhancement layer 3

Enhancement layer 4

Frame 2

Base layer

Enhancement layer 1

Enhancement layer 2

Enhancement layer 3

Enhancement layer 4

Frame 3

Base layer

Enhancement layer 1

Enhancement layer 2

Enhancement layer 3

Enhancement layer 4

Frame 4

Base layer

Enhancement layer 1

Enhancement layer 2

Enhancement layer 3

Enhancement layer 4

Frame 5

Scalable Video Authentication

Any number of enhancement layers may be dropped Non-scalable video/stream auth schemes do not work


Any number of enhancement layers may be dropped Non-scalable video/stream auth schemes do not work

Authenticating only the base layer Not enough


Extending the hash chaining to 2D

Base layer

Enhancement layer 1

Enhancement layer 2

Frame 1 Frame 2

Hash

Hash

Base layer

Enhancement layer 1

Enhancement layer 2

Hash

Hash

Hash


Extending the hash chaining to 2D Erasure Correction

Codes (ECC)can be usedfor toleratingpacket loss

Base layer

Enhancement layer 1

Enhancement layer 2

Frame 1 Frame 2

Hash

Hash

Base layer

Enhancement layer 1

Enhancement layer 2

Hash

Hash

Hash




No online production Base layer

Enhancement layer 1

Enhancement layer 2

Frame 1 Frame 2

Hash

Hash

Base layer

Enhancement layer 1

Enhancement layer 2

Hash

Hash

Hash




No online production

Communicationoverhead

Base layer

Enhancement layer 1

Enhancement layer 2

Frame 1 Frame 2

Hash

Hash

Base layer

Enhancement layer 1

Enhancement layer 2

Hash

Hash

Hash

Conclusion

No previous scheme meets all of the requirements

Conclusion

No previous scheme meets all of the requirements

Future research directions Multimedia-devoted hash functions

Support for modern video coding standards FGS, MGS

The case of P2P streaming Taking advantage of distribution of peers

Thank You

Any Questions?

Main References

Stallings, W., “Cryptography and network security: principles and practices,” 4th Edition, Prentice Hall, 2006.

“Streaming media, iptv, and broadband transport: Telecommunications carriers and entertainment services 2006-2011,” The Insight Research Corporation, Technical Report, April 2006, http://www.insight-corp.com/execsummaries/iptv06execsum.pdf.

Gennaro, R., and Rohatgi, P., “How to sign digital streams,” in Advances in Cryptology (CRYPTO’97), Santa Barbara, CA, August 1997, LNCS vol. 1294, pp. 180–197.

Park, J., Chong, E. and Siegel, H., “Efficient multicast stream authentication using erasure codes,” ACM Transaction on Information and System Security (TISSEC), vol. 6, no. 2, pp. 258–285, May 2003.

Li, W., “Overview of fine granularity scalability in MPEG-4 video standard,” IEEE Transactions on Circuits and Systems for Video Technology, vol. 11, no. 3, pp. 301–317, March 2001.

Wu, Y., and Deng, R., “Scalable authentication of MPEG-4 streams,” IEEE Transactions on Multimedia, vol. 8, pp. 152–161, February 2006.

KIANOOSH MOKHTARIAN SCHOOL OF COMPUTING SCIENCE SIMON FRASER UNIVERSITY 3/24/2008 Secure Multimedia Streaming.

Documents

hashmedia slide

entire media

frame slide

repudiatable slide

expensive slide

authentic slide

sign hashmedia

case of multimedia