METHOD AND APPARATUS FOR CIPHERTEXT INDEXING AND SEARCHING

摘要

PPROBLEM TO BE SOLVED: To provide a method and apparatus for creating and using indices of multiple levels which provide good security and privacy and enable easy and convenient updating. PSOLUTION: The present invention provides a method and apparatus for ciphertext indexing and searching. Indices of multiple levels are created for the encrypted files. Each item in the primary index includes a primary index item identifier and the ciphertext of the primary indexing information of the related file. The primary indexing information each includes an identifier(s) of the related secondary index item identifier(s) and the corresponding decryption information. Each item in the secondary index includes a secondary index item identifier and the ciphertext of the secondary indexing information. Information necessary for obtaining a file is included in the corresponding secondary indexing information. With the decryption information of the secondary indexing information included in the decrypted primary indexing information, the ciphertext of the related secondary indexing information is decrypted to obtain information such as the decryption key of the file. PCOPYRIGHT: (C)2010,JPO&INPIT