| 摘要 |
<p>PROBLEM TO BE SOLVED: To cipher and decipher data fast without spoiling the feature of high-speed transfer of a hologram memory. SOLUTION: Ciphered object light is generated by exclusively ORing transmitted data to be ciphered and secret key data for ciphering and recorded as a hologram in an optical recording medium 10. For its read, the optical recording medium 10 is irradiated with the same readout light 12 as the reference light for the recording and a reproduced image 11 is diffracted from the hologram to the optical path of the object light. At the same time, a secret key image 13 having a polarization direction orthogonal to the polarization direction of the reproduced image 11 is generated, transmitted through the optical recording medium 10, and imaged on the optical path of the reproduced image 11 to interfere with the reproduced image 11. A polarizer 42 is arranged on the common optical path of the reproduced image 11 and secret key image 13 and the direction of its transmission axis is made orthogonal to the direction of the composite vector of the polarized light of the reproduced image 11 and the polarized light of the secret key image 13. Consequently, a ciphered data image of exclusive OR between the reproduced image 11 and secret key image 13 is obtained as light having been transmitted through the polarizer 42.</p> |
