| 摘要 |
PURPOSE: An apparatus for protecting data of a digital magnetic recording and playback system is provided to reinforce encryption of recorded data and improve the security of the recorded data. CONSTITUTION: An encryption part(14) enciphers an input video signal ECC(Error Correction Code) encoded after being converted into a digital signal and then compressed. A key generating part(17) generates a secret key by using identification information of a smart card for encryption of the encryption part, public information which is common information to all users, and first and second random numbers. The smart card(16) generates the secret key, connecting with the key generating part, and keeps the generated secret key. A deciphering part(19) deciphers reproduced data by using the secret key in reproducing the enciphered data.
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