Title :
Speech privacy for modern mobile communication systems
Author :
De Andrade, José F., Jr. ; De Campos, Marcello L R ; Apolinário, José A., Jr.
Author_Institution :
Electr. Eng. Program, Fed. Univ. of Rio de Janeiro, Rio de Janeiro
fDate :
March 31 2008-April 4 2008
Abstract :
Speech privacy techniques are used to scramble clear speech into an unintelligible signal in order to avoid eavesdropping. Some analog speech-privacy equipments (scramblers) have been replaced by digital encryption devices (comsec), which have higher degree of security but require complex implementations and large bandwidth for transmission. However, if speech privacy is wanted in a mobile phone using a modern commercial codec, such as the AMR (adaptive multirate) codec, digital encryption may not be an option due to the fact that it requires internal hardware and software modifications. If encryption is applied before the codec, poor voice quality may result, for the vocoder would handle digitally encrypted signal resembling noise. On the other hand, analog scramblers may be placed before the voice encoder without causing much penalty to its performance. Analog scramblers are intended in applications where the degree of security is not too critical and hardware modifications are prohibitive due to its high cost. In this article we investigate the use of different techniques of voice scramblers applied to mobile communications vocoders. We present our results in terms of LPC and cepstral distances, and PESQ values.
Keywords :
cryptography; data privacy; linear predictive coding; mobile communication; mobile handsets; speech processing; telecommunication security; vocoders; cepstral distance; digital encryption device; linear predictive coding; mobile communication system; mobile phone; perceptual evaluation of speech quality; speech privacy; unintelligible speech signal; vocoder; voice scrambler; Application software; Bandwidth; Communication system security; Cryptography; Hardware; Mobile communication; Mobile handsets; Privacy; Speech codecs; Vocoders; AMR; Speech privacy; adaptive multirate codec; mobile communications; scramblers;
Conference_Titel :
Acoustics, Speech and Signal Processing, 2008. ICASSP 2008. IEEE International Conference on
Conference_Location :
Las Vegas, NV
Print_ISBN :
978-1-4244-1483-3
Electronic_ISBN :
1520-6149
DOI :
10.1109/ICASSP.2008.4517975