On the use of a frequency domain vector codebook for the cryptanalysis of analog speech scramblers
B. Goldburg, Sridha Sridharan, Ed Dawson · 1991
The authors present a novel application for a frequency domain codebook, similar to that used in the vector quantization of speech. It is shown that such a codebook can be used to cryptanalyze commonly used analog speech scramblers such as the bandsplitter and DFT (discrete Fourier transform) based encryption systems. In each case intelligible speech can be recovered using about three seconds of encrypted speech.>