| 摘要 |
PROBLEM TO BE SOLVED: To prevent information leakage from secret data for identifying other users present near a specific user.SOLUTION: First data for identifying a block which includes a time of day and a position identified by time of day and position data among a plurality of time and space blocks that can be obtained by splitting a time and a space by a prescribed unit and second data for identifying a relative time of day and position inside the block are extracted from the time of day and position data, secrecy processing is performed to the first data, and a data block including a user ID, the first data after the secrecy processing is performed, and the second data is stored. When relative time of day and position inside the block that are identified by the second data are within a predetermined range from a boundary of the block, a data block about an adjacent block having a similar data format is generated and stored. Then, the stored data block is transmitted to a computer at random. |
