ID based public key cryptosystems based on Okamoto and Tanaka´s ID based one way communication scheme

With a slight modification to Okamoto and Tanaka´s ID based one way communication scheme (see IEEE J. Select. Areas Commun., vol.7, no.4, p.481-5, 1989), two identity based public key cryptosystems are proposed. These systems do not possess the conspiracy problem and can withstand certain key attack common to most public key cryptosystems.