Patent ID: 7526645

Claim:
An electronic document redacting system comprising: a first electronic calculator executing a first program embodied in a storage medium, which creates a disclosure object electronic document including at least an original electronic document comprising a plurality of constituent elements and authenticity assurance data; and a second electronic calculator executing a second program embodied in a storage medium, which creates a disclosure electronic document by implementing a redacting process to the disclosure object electronic document, wherein the first electronic calculator implements the first program and executes a series of processes comprising: (a) a process which creates additional redacted control data with respect to each of the constituent elements of the original electronic document and calculates a hash value by means of an input of the additional redacted control data as a cryptographic hash function as well as calculating a hash value by means of an input of the constituent element as a cryptographic hash function; (b) a process which creates one electronic signature of the disclosure object electronic document creator by means of the hash values calculated by the process (a); (c) a process which creates the authenticity assurance data including the additional redacted control data created by the process (a) and the electronic signature, and (d) a process which creates the disclosure object electronic document including the original electronic document and the authenticity assurance data; and wherein the second electronic calculator implements the second program and executes a series of processes comprising: (e) according to the plurality of the constituent elements constituting the original electronic document, a process which checks a presence of any redacted constituent element which is made redacted and a disclosure constituent element which is prohibited to be an additional redacted process; (f) according to each of the redacted constituent elements, a process which calculates a hash value by means of an input of the redacted constituent element as the cryptographic hash function as well as calculating a hash value by means of an input of the additional redacted control data of the authenticity assurance data corresponding to each of disclosure elements which prohibits the additional redacted process; (g) a process which creates a second authenticity assurance data, which is an updated version of the authenticity assurance data, by including the hash value calculated in accordance with the redacted constituent element into the authenticity assurance data and substituting the additional redacted control data of the authenticity assurance data corresponding to disclosure constituent element which prohibits the additional redacted process into the corresponding calculated hash value, and (h) a process which creates a disclosure electronic document including the constituent element of the original electronic document except the redacted constituent element and the second authenticity assurance data.