| 摘要 |
PROBLEM TO BE SOLVED: To permit decryption by an encryption system privileged person, only when needed. SOLUTION: An encryption data generating apparatus 1 generates encryption data, by generating session key pre-information that is information specifying a session, generating a session key on the basis of a set of the generated session key pre-information and user public key generated, on the basis of a privilege public key Ppub; using the session key pre-information and the privilege public key; generating decryption information that is information required for generating the session key, on the basis of a decryption possibility/impossibility information that is a designation signal indicating whether to permit decryption by the privileged person, encrypting electronic data by means of the session key, and imparting the decryption information to the encrypted electronic data. COPYRIGHT: (C)2009,JPO&INPIT
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