Client-side caching for TLS

Abstract

We propose two new mechanisms for caching handshake information on TLS clients. The "fast-track" mechanism provides a client-side cache of a server's public parameters and negotiated parameters in the course of an initial, enabling handshake. These parameters need not be resent on subsequent handshakes. Fast-track reduces both network traffic and the number of round trips, and requires no additional server state. These savings are most useful in high-latency environments such as wireless networks. The second mechanism, "client-side session caching," allows the server to store an encrypted version of the session information on a client, allowing a server to maintain a much larger number of active sessions in a given memory footprint. Our design is fully backward-compatible with TLS: extended clients can interoperate with servers unaware of our extensions and vice versa. We have implemented our fast-track proposal to demonstrate the resulting efficiency improvements.