CIPHER COMMUNICATION SYSTEM, TERMINAL DEVICE, AND SECRET KEY GENERATING METHOD, AND PROGRAM

摘要

<P>PROBLEM TO BE SOLVED: To enable a transmitting side terminal device to generate a cipher text by using the ID of a receiving side terminal device and a public parameter, and further to avoid escrow properties. Ž<P>SOLUTION: A key generation device 10 uses a master secret key and public ID information corresponding to any user, generates a first secret key of a hierarchical ID-based encryption method using the public ID information as an ID, and outputs the first secret key. A terminal device 30 uses the first secret key and secret ID information and generates a second secret key of the hierarchical ID-based encryption method using a set of the public ID information and the secret ID information as an ID. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž