| 摘要 |
PURPOSE:To reduce management information even at the time of enciphering plural files by different keys by giving a hierarchical reference permission to a user, in the sharing method of a ciphered file. CONSTITUTION:In a wide area distributed type data processor in which plural data processors are mutually connected by a network, and the files are shared by the plural users while each privacy is kept, a file F is ciphered by a cipher key, the ciphered file is stored in a directory ID having a hierarchical tree structure, the same cipher key is assigned to each directory, and the file having the same access attribute is ciphered by the same key, in the data processor being a file server S. Then, the ciphered file is transferred on a network N, and a local deciphering or ciphering is operated by a ciphering and deciphering part 1 at the user side. |
