Security Analysis of Server-Aided Public Key Generation Protocols on Low-Power Devices for Ad-Hoc Networks

In ITST2006, Chen et al. presented two server-aided public key generation protocols for low-power devices and claimed that their protocols secure against collusion attack. In this paper, we point that if the servers collude with each other, those servers could obtain low-power devices' secret information, and they can get the plaintext from any ciphertext. We also present an improved server-aided standard RSA key generation protocol against the collusion attack.