On Improved Efficiency and Forward Security of 0-RTT Key Exchange for SDP

The Transport Layer Security (TLS) protocol has been widely used in software-defined perimeter (SDP) to establish secure, encrypted connections between distributed SDP components. To improve communication efficiency of its handshake protocol, the latest TLS standard (i.e., TLS 1.3) introduces a zero round-trip-time (0-RTT) handshake. However, traditional 0-RTT handshake protocols lack a forward secure key exchange scheme, so encrypted data that have already been transmitted could be potentially leaked to attackers after the pre-shared key (PSK) is compromised. To achieve secure TLS handshake with minimal communication cost, several forward secure 0-RTT key exchange schemes based on puncturable encryption were proposed. However, they are not applicable to real world SDP environments, because they either need to pre-store a large number of secret keys in the host onboard phase, or require a large number of complex cryptography operations (e.g., bilinear-pairing) in the access phase. Therefore, to avoid high computational overhead while still maintaining communication efficiency and forward security, a novel 0-RTT key exchange scheme based on efficient puncturable key encapsulation mechanism is proposed in this paper. Experimental results show that, with reasonable (and configurable) memory consumption, the latency performance of the proposed scheme is about 30% better than FFDHE3072, which is a practical 1-RTT key exchange scheme in TLS 1.3.