Patent ID: 11902418
Assignee: MITSUBISHI ELECTRIC CORPORATION
Field: Digital communication (Electrical engineering)
Classification: CPC H  G | IPC G  H

Claim 1:
2. The search operation device according to claim 1,
wherein the processing circuitry is further configured to:
transmit the search query and receives an encrypted search result including ciphertext data matching the search query; and
decode the ciphertext data included in the encrypted search result into plaintext by using a user data key included in the user key,
wherein the user data key has a plurality of flag values based on the plurality of attribute values and one or more data attribute keys based on one or more aggregate values generated by aggregating the plurality of attribute values, and
wherein the processing circuitry is further configured to:
generate a decoding-purpose aggregate flag indicating one or more aggregate values each configured of one or more flag values, by aggregating the plurality of flag values included in the user data key,
generate, by using the decoding-purpose aggregate flag, decoding position information which identifies one or more attribute elements for use in decoding among a plurality of attribute elements included in the ciphertext data in the encrypted search result, and
decode the ciphertext data included in the encrypted search result into the plaintext by using the one or more data attribute keys included in the user data key and the decoding position information.