Encrypted communication system, encrypted communication method, encrypting device, and decrypting device

Abstract

To allow viewers to view a plain document depending on levels of the authorized powers of the viewers without inserting identifiers into the plain document. An encrypting device includes devices for: storing encrypting role information which includes encrypting keys and key IDs of the encrypting keys; grasping the encrypting range of the plain document, and creating an encrypted part by encrypting the encrypting range using the encrypting key in the encrypting role information; creating the encrypting information configured with one, two, or more record(s) containing the front position and rear position of the encrypted part, the key ID corresponding to the encrypting key that is applied for the encrypted part, and the processing order of the encrypted part; creating the encrypted document by combining an encrypted document main body configured with a document containing the encrypted part with the encrypting information; and storing the encrypted document to a prescribed medium.