Patent Document ID: 8218188
Application ID: 11153418

Base Claim:
1. An electronic document storage apparatus for storing an electronic document, comprising: an electronic document storage unit for storing a registered electronic document for a specified period of time; an electronic document management unit for storing at least a status, a date of registration and an access history of the registered electronic document; a transfer process unit for transferring to an archive media an electronic document registered prior to a defined date from among electronic documents stored in the electronic document storage unit by referring to information stored in the electronic document management unit; and a key management unit decodes reference history information encoded by an electronic document reference apparatus and stored in the archive media, by using a write key paired with a read key used for encoding the reference history information, where the reference history information indicates reference to the electronic document, and wherein the transfer process unit calculates a hash value of the electronic document, and after encoding the calculated hash value using the write key used when the key management unit encodes the electronic document, stores the encoded hash value in the archive media, the electronic document reference apparatus calculates a hash value of the electronic document stored in the archive media, and decodes the electronic document stored in the archive media using the read key stored in a for-reference management information emigration media when the calculated hash value matches a hash value obtained by decoding the hash value stored in the archive media using the read key stored in the for-reference management information emigration media, the write key and the read key are configured to be changed at a specified timing, and the electronic document reference apparatus decodes the electronic document stored in the archive media by using the read key paired with the write key used when the electronic document was transferred by the transfer process unit.

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Claim 4:
4. The electronic document storage apparatus according to claim 1 , wherein the key management unit, includes: an encryption key creation unit for creating a pair of keys made up of encryption keys by a public key encryption system, and a for-management key table for managing the pair of keys being created by the encryption key creation unit through assigning key ID as a load key for one of the pair of keys and a read key for the other thereof, for enciphering by using the load key when there is a request for enciphering, wherein said transfer process unit requests the key management unit for enciphering an electronic document as the object of transfer followed by transferring the aforementioned electronic document to an archive media.