KIANOOSH MOKHTARIAN SCHOOL OF COMPUTING SCIENCE SIMON 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 Multimedia streaming: a great source of revenue  Its market will grow from $900 mln in 2005 to $6 bln in 2011 Affecting our daily lives

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

What Security Aspects? 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 x 1 and x 2 such that H(x 1 ) = H(x 2 )  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) )

Conventional Auth’: the Case of Multimedia 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

Conventional Auth’: the Case of Multimedia 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

Conventional Auth’: the Case of Multimedia 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  Computationally expensive

Conventional Auth’: the Case of Multimedia 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  Computationally expensive Using Message Authentication Codes (MAC)  y = MAC K ( x ) = Hash ( x || K )

Conventional Auth’: the Case of Multimedia 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  Computationally expensive Using Message Authentication Codes (MAC)  y = MAC K ( x ) = Hash ( x || K )  Cannot go beyond single-sender single-receiver case

Requirements

Security!

Requirements Security! Online production, online verification

Requirements Security! Online production, online verification Computational cost

Requirements Security! Online production, online verification Computational cost Communication overhead

Requirements Security! Online production, online verification Computational cost Communication overhead Buffer needed for authentication purposes

Requirements Security! Online production, online verification Computational cost Communication overhead Buffer needed for authentication purposes Robustness against adaptations on the media  Whether to get the proxies involved or not

Requirements Security! Online production, online verification Computational cost Communication overhead Buffer needed for authentication purposes Robustness against adaptations on the media  Whether to get the proxies involved or not Tolerability of packet losses in network

Requirements Security! Online production, online verification Computational cost Communication overhead Buffer needed for authentication purposes Robustness against adaptations on the media  Whether to get the proxies involved or not Tolerability of packet losses in network Supported scenarios

Stream Authentication Hash chaining

Stream Authentication Hash chaining  No online production of the authenticated stream

Stream Authentication Hash chaining  No online production of the authenticated stream  Sensitive to any packet loss

Stream Authentication One-time signature  Based on conventional (symmetric) cryptographic functions One-time signature chaining

Stream Authentication One-time signature  Based on conventional (symmetric) cryptographic functions One-time signature chaining  High communication overhead

Stream Authentication One-time signature  Based on conventional (symmetric) cryptographic functions One-time signature chaining  High communication overhead  Sensitive to any packet loss

Stream Authentication SAIDA: Signature Amortization using IDA (Information Dispersal Algorithms)

Stream Authentication SAIDA: Signature Amortization using IDA (Information Dispersal Algorithms)  Tradeoff between verification delay and overheads

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

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

Scalable Video Authentication Any number of enhancement layers may be dropped  Non-scalable video/stream auth schemes do not work Authenticating only the base layer  Not enough

Scalable Video Authentication Extending the hash chaining to 2D

Scalable Video Authentication Extending the hash chaining to 2D  Erasure Correction Codes (ECC) can be used for tolerating packet loss

Scalable Video Authentication Extending the hash chaining to 2D  Erasure Correction Codes (ECC) can be used for tolerating packet loss  No online production

Scalable Video Authentication Extending the hash chaining to 2D  Erasure Correction Codes (ECC) can be used for tolerating packet loss  No online production  Communication overhead

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, “Streaming media, iptv, and broadband transport: Telecommunications carriers and entertainment services ,” The Insight Research Corporation, Technical Report, April 2006, 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 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 Wu, Y., and Deng, R., “Scalable authentication of MPEG-4 streams,” IEEE Transactions on Multimedia, vol. 8, pp. 152–161, February 2006.