| 摘要 |
PROBLEM TO BE SOLVED: To allocate a medium specific number to a medium, to provide approval for executing software to the medium specific number, to store the medium specific number in a normal medium, and to execute only the approved software. SOLUTION: An electronic data protection system is provided with a medium 1 for storing ciphered electronic data 14 and a medium specific number 12 specified to the medium 1 itself and a medium 2 for storing approval information 13 and constituted so as to generate a medium specific key on the basis of the specific number 12 of the medium 1, cipher an electronic data deciphering key by the medium specific key and write the ciphered key in the medium 2 as the approval information 13 on the approve side and so as to generate a medium specific key on the basis of the medium specific number 12 read out from the medium 1, generate electronic data deciphering key by deciphering the approval information 13 read out by the medium specific key and decipher the read ciphered electronic data 14 by the electronic data deciphering key to obtain plaintext electronic data on the user side. |
