Provided is a technology with which an electronic document including a plurality of elements such as texts and images may be partially encrypted and decrypted. An encryption-processing control unit receives a selection of electronic data included in an electronic document and a selection of an encryption key for encrypting the electronic data from among encryption keys stored in a storing unit. The encryption-processing control unit generates encrypted area data including partially encrypted data obtained by encrypting the selected electronic data with the selected encryption key, positional information for specifying a position of the selected electronic data in the electronic document, and decryption information including information that may specify a decryption key with which the partially encrypted data may be decrypted, and adds the encrypted area data to the electronic document.