A novel secure H.264 transcoder using selective encryption

NM Thomas, D Lefol, DR Bull, DW Redmill

Research output: Chapter in Book/Report/Conference proceedingConference Contribution (Conference Proceeding)


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.
Translated title of the contributionA novel secure H.264 transcoder using selective encryption
Original languageEnglish
Title of host publicationIEEE International Conference on Image Processing (ICIP 2007), San Antonio
PublisherInstitute of Electrical and Electronics Engineers (IEEE)
Pages85 - 88
Number of pages4
ISBN (Print)9781424414369, 9781424414376
Publication statusPublished - 16 Sep 2007


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