| 摘要 |
PURPOSE:To realize the picture scramble device able to attain data compression and immune to attack to a known plain sentence with respect to the picture scramble device for ciphering communication of a picture data subject to digital coding. CONSTITUTION:An input data is rearranged at random at a signal rearrangement device under the condition that preceding and succeeding picture elements are converted into any of upper/lower/left/right picture element at all times, the result is compression-coded at an orthogonal transformation coder 2 and processed by an equal length signal processing unit 3 and a transposition processing unit 4, then a scramble signal is generated. Thus, the object is attained and also block distortion caused by compression coding is not visually remarkable. |
