Bae Eun Jung
On the Chikazawa-Inoue ID based key system
In this paper, we show that Chikazawa-Inoue ID-based key system is insecure by collusion, where Chikazawa-Inoue ID-based key system means the key parameters established during the initiation phase. We describe an algorithm factorizing a public key of Trust Center. Since our attack is based on only the key system and has no relation with specific key sharing protocols, it can be applied to all variant protocols of Chikazawa-Inoue ID based key sharing protocol. From this analysis, we obtain conclusions that Chikazawa-Inoue ID-based key system cannot be used any more for any application protocols.