Patent Document ID: 7882083
Application ID: 11985101

Base Claim:
1. A computer-readable recording medium storing therein an information retrieval program to retrieve information from content that includes a plurality of files and causing a computer to execute: generating compression information of the content including character data extracted from the content, an occurrence frequency of each of the character data in the content, and presence/absence information concerning a presence/absence of each of the character data in each of the files, wherein when the character data includes combined character data representing a predetermined sequential phonogram string, the combined character data is substituted by supplementary character data; compressing the content to form a plurality of compressed files based on the occurrence frequency; extracting a target file from among the compressed files based on the presence/absence information; and decompressing the target file, wherein when the supplementary character data is included in the target file, the supplementary character data is substituted by the combined character data.

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Claim 9:
9. The computer-readable recording medium according to claim 1 , wherein the computer program further causes the computer to execute encrypting the compression information.