Secure Scalable Multimedia Streaming

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Secure Scalable Multimedia Streaming

• Karl MartinMultimedia LabDept. of Electrical
  and Computer Eng. University of Toronto

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I. Introduction

• Communications becoming more multimedia in nature
  images, video, and text
• The key to Universal Multimedia Access (UMA) is
  content scalability
• Efficient content streaming is achieved via a
  transcoding server which scales the content to
  meet user needs and network conditions

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I. Introduction
PossiblyUntrusted
Scalable Content
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I. Introduction

• Problem
• How do we maintain scalability while keeping the
  content confidential?
• Scalability has traditionally been seen to be in
  fundamental conflict with security
• Can we encrypt the content and subsequently have
  a transcoding server scale it without knowledge
  of the decryption key?

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II. Secure Scalable Multimedia Streaming (SSMS)

• Structure the content using XML (MPEG-21 Digital
  Item)
• Structure matches the packetized scalability
  components of the content
• Separately encrypt scalability components using
  progressive encryption
• Include unencrypted metadata hint tracks which
  instruct the transcoder how to scale the content
  without decryption

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II. SSMS Video Example
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II. SSMS Video Example

• Scalability modalities frame-rate, distortion,
  resolution, etc.
• Hint tracks allow transcoding server to truncate
  and remove appropriate packets without decryption

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II. SSMS Generic Media

• Concept to be extended to images(e.g., JPEG
  2000) and documents
• XML-based documents (e.g., MS Office Open XML,
  OpenDocument Format)
• Document schema used to determine supported
  scaling modalities
• Content pre-analysis used to determine discrete
  scaling points (e.g., levels of summarization)
• SSMS scheme will also enable implementation of
  complex security policies