Abstract: Method and apparatus for encrypting and subsequently decrypting an analog or digital signal are disclosed. During encryption the signal waveform is transformed by a substantially continuous non-linear complex function of frequency. The transformation is characterized in that the time duration of a transformed impulse signal is substantially increased. Decryption requires transformation of the encrypted signal by substantially the complex inverse of the encryption function. The transformations may vary in time during encryption/decryption of a signal.
Type:
Grant
Filed:
January 16, 1990
Date of Patent:
March 31, 1992
Assignees:
Cardinal Encryption Systems Ltd., Joseph Alfred Webb