A file editing system that provides a high file content secrecy, a file version management and an asynchronous editing is disclosed. For a high file content secrecy, the block data of files managed by a file management server device are enciphered in units of blocks, and a client device obtains the block...http://www.google.de/patents/US7631185?utm_source=gb-gplus-sharePatent US7631185 - File editing system and shared file editing system with file content secrecy, file version management, and asynchronous editing
