| 摘要 |
PCT No. PCT/GB84/00106 Sec. 371 Date Nov. 20, 1984 Sec. 102(e) Date Nov. 20, 1984 PCT Filed Mar. 28, 1984 PCT Pub. No. WO84/04013 PCT Pub. Date Oct. 11, 1984.A method of encrypting a television signal having in each ruster scan line a digital section of information and chrominance and luminance sections of information comprising cutting either or both of the chrominance and luminance sections and rotating the cut sections within a normal line period. If one of the sections is uncut, it may be translated in time with respect to the line period by having one of the rotated cut sections placed before the uncut section and one placed after the uncut section. The cutting point or points are determined by a pseudo random number generator. Receiving apparatus for receiving such an encrypted signal is also disclosed in which a complementary pseudo random number generator is used responsive to receipt of an encryption key to control addressing of a descrambling store in order to reconstitute the original signal.
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