A KEM/DEM-Based Construction for Secure and Anonymous Communication

Public key infrastructure has been widely used, but its certificate must be removed when a corresponding public key is sent via an anonymous communication channel in order to maintain anonymity. It is because the certificate contains information of the key holder, and that contradicts anonymity. A secure and anonymous communication protocol was proposed to address this issue, where end-to-end encryption and anonymous authentication are achieved simultaneously. It applies identity-based encryption (IBE) for packet encryption. However, because IBE requires heavy pairing computations, this protocol is inefficient and approximately 20 times slower than that of SSL communications. In this paper, we propose a more efficient, secure, and anonymous communication protocol, which achieves the same security level as the IBE-based protocol does. The protocol is exempted from pairing computation for establishing a secure channel by applying hybrid encryption instead of IBE. We implement the protocol and show that it is more efficient (overall approximately 1.2 times faster) than the IBE-based protocol. In particular, the decryption algorithm of our protocol is several hundred times faster than that of the IBE-based protocol.