A Note on Secure Key Issuing in ID-based Cryptography.
Chunxiang Xu, Junhui Zhou, Zhiguang Qin · IACR Cryptology ePrint Archive · 2005
Most recently, Lee B. et al proposed a key issuing protocol for ID-based cryptography to solve the key escrow problem. However in this letter, we show that a malicious key generation center (KGC) can successfully attack the protocol to obtain users’ private keys. This means that in the protocol, the key escrow problem isn’t really removed.