A new key generation method for frequency-domain speech scramblers
Raymond W. M. Woo, Cyril Leung · IEEE Transactions on Communications · 1997
This paper describes a method which uses "derangement" permutations as scrambling keys in a frequency-domain speech scrambling system. Subjective tests based on the number test confirm that such keys produce scrambled speech with virtually no residual intelligibility. A new derangement generation algorithm is introduced for key generation. This algorithm maps each integer g, in the range of 0/spl les/g<(n-1)!, to a distinct derangement of 2 elements,.