A digital secure speech communication system realized on DSP

摘要

As speech communications become more widely used and even more vulnerable, the problems of providing some form of privacy or, in some cases, a high level of security is dramatically increasing in importance. Both analogue scramblers and digital scramblers can provide secure speech communication on different security levels. This paper introduces a new 256-bit randomised block cipher and illustrates how to realize it on a Digital Signal Processor (DSP) that provides high level secure speech communication. Since all speech security systems reduce the audio quality of the voice transmission, it is important that we ensure that the level of degradation is not too high. A high audio quality of Mean Opinion Score 4 was obtained when we employed International Telecommunications Union (ITU) G.726 as the vocoder in our case study.