A novel secure H.264 transcoder using selective encryption

DW Redmill, Nithin M Thomas, D Lefol, David Bull

Research output: Contribution to conferenceConference Abstract

31 Citations (Scopus)
467 Downloads (Pure)


In digital broadcast TV systems, video data is normally encrypted before transmission. For in-home redistribution, it is often necessary to transcode the bitstream to achieve optimum utilization of available bandwidth. If a signal is decrypted before transcoding and re-encrypted, this may lead to a security loophole. This paper presents a solution in the form of a novel H.264 selective encryption algorithm that encrypts sign bits of transform coefficients and motion vectors to allow secure transcoding without decryption. The performance of this system is compared with I-frame encryption. The results show that sign encryption is more secure than I-frame encryption and has a lower complexity. A hybrid system using a modified transcoder and sign encryption is found to give an optimal compromise between security and transcoding performance.
Original languageEnglish
PagesIV-85 - IV-88
Publication statusPublished - Sept 2007

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Name of Conference: International Conference on Image Processing
Venue of Conference: San Antonio, USA


  • TV broadcasting
  • video coding
  • security
  • cryptography


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