| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a system capable of performing scrambling/descrambling with high security, a scramble circuit and a descramble circuit. <P>SOLUTION: The scramble circuit 3 sets a filter coefficient temporally changing to an FIR filter 1 and scrambles an original video signal on the basis of the set filter coefficient, and superimposes an inverse filter coefficient on a scrambled video signal to provide an output of a transmission / storage video signal. The descramble circuit 4 extracts the inverse filter coefficient from the transmission / storage video signal, sets the inverse filter coefficient to a descramble FIR filter 2, and descrambles the transmission / storage video signal to obtain a decrypted video signal. Since a prescribed filter characteristic cannot be obtained through the circuit analysis by using the filter coefficient that temporally varies, the scramble security can be enhanced. <P>COPYRIGHT: (C)2004,JPO</p> |
