The present invention reduces the storage capacity of encrypted search assist data used in a process of complete-match search for encrypted data to be searched. A search assist data storage device (10) is provided with an encryption start point array storage unit (11) and an encryption search result array storage unit (12). The encryption start point array storage unit (11) stores encryption keyword information and encryption start point information in correlation. The encryption keyword information is information in which a keyword is encrypted. The encryption start point information is information in which the data identifier of a start point in the data identifier list (search result list) of data to be searched that completely matches the keyword is encrypted. The encryption search result array storage unit (12) stores encryption preceding/following identifier information and encryption preceding/following identifier key information in correlation. The encryption preceding/following identifier information is information in which each data identifier in the search result list and data identifiers preceding and following the same are encrypted by preceding/following identifier key information. The encryption preceding/following identifier key information is information in which preceding/following identifier key information is encrypted.
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