PERCEPTION-BASED SELECTIVE ENCRYPTION OF G.719 SPEECH
Antonio Servetn, Corso Duca · 2002
Mobile multimedia applications, the focus of many forth coming wireless services , increasingly demand low -power techniques impl ementin g content protection and customer privacy. In this paper a low -complexity, perception-based partial encryption scheme for telephone-bandwidth speech is presented. Speech compressed by a widely-used speech coding algorithm, ITU- T G.729 CS-ACELP at 8 kbls, is par titioned in two classes, one, the most perceptually relevant, to be encrypted, the other, to be left unprotected. Encryp tion of about 45% of the bitstream achieves content protec tion equivalent to full encryption of the bitstrea m, as verified by both objecti ve measures and formal listening tests. Low power, portable devices can, therefore, implement very high levels of speech-content protection at a fraction of the com putational load of current techniq ues, freeing resources for other tasks and enabling longer battery life.