| 摘要 |
PROBLEM TO BE SOLVED: To process a Vernam cipher at a high speed with pseudo random numbers setting data of a picture to be a seed signal as a ciphering key. SOLUTION: Polarizing plates 381 and 382, liquid crystal panels (LCP) 401-403 and diffraction elements(DE) 561-564 in a ciphering key generation part 44 constitute an optical exclusive OR arithmetic unit calculating three bits of respective pixels in LCP. DE guide the correspondence of the respective picture elements, which is to be calculated. A pattern corresponding to an initial value vector (seed signal at first) is displayed on LCP 401. Random bit strings corresponding to the pixels of LCP can be obtained as the ciphering keys by image- picking up output light from the polarizing plate 388 and A/D-converting it. The keys are displayed on LCP 404 of the optical exclusive OR arithmetic unit consisting of the polarizing plates 383 and 384 and LCP 404 and 405 in a ciphering part 46, and digital data which is to be ciphered is displayed on LCP 405. Output light from the polarizing plate 384 is image-picked up, is A/D- converted and is outputted as the Vernam cipher. |
