IBE and Digital Signature Apparatus and Method, and Server for Providing Secret key

摘要

PURPOSE: An apparatus and method for identity based encryption and digital signature and a secret key issuing server and method are provided to recognize a security file with the naked eye using an ID, which is used in the ID base encryption, as a file extension. CONSTITUTION: Screen generation parts(251,351) generate a screen for receiving an ID of a receiver who receives a first file from a user. Encryption parts(252,352) encrypt the first file by using the receiver ID, which is inputted in the generated screen, as a public key. The encryption part uses the receiver ID as a file extension for the encrypted first file. The encryption part hierarchically encrypts the first file by successively using a plurality of IDs. The encryption part uses the plurality of IDs as the extension for the encrypted first file. [Reference numerals] (250) First ID base processing module; (251) First screen generation part; (252) First encryption part; (253) First decryption part; (254) First digital signature part; (255) First verification part; (350) Second ID base processing module; (351) Second screen generation part; (352) Second encryption part; (353) Second decryption part; (354) Second digital signature part; (355) Second verification part