Patent ID: 7043496

Claim:
A data managing system, comprising: a client unit which a user uses to request for data; an agent unit which saves encrypted document data and attributes information; a document managing unit which executes user authentication, access control and document image edition by means of decrypting of encrypted document data; wherein each said unit has a processing function and an interface function which are independent of each other, and are connected via a communication network, and wherein when document data have an output image in which a plurality of lines of particulars data are described between a predetermined page header and page footer, a necessary multi-layer hierarchical index file is constructed which contains a lowest-order index file formed by said page header, said page footer and storing location data of said particulars data, a higher-order index file formed by index keys, index items and said storing location data of said lowest-order index file by blocking said lowest-order index file, and a further higher-order index file formed by blocking said upper index file, and in response to a data request from said client unit, lower-order index files are sequentially specified from said higher-order index file by means of transactions between said client unit and said document managing unit, whereby data requested by a user are specified and provided.