A secure, publisher-centric Web caching infrastructure

The current Web caching infrastructure, though it has a number of performance benefits for clients and network providers, does not meet publishers' requirements. We argue that to satisfy these requirements, caches should be enhanced in both the data and control planes. In the data plane, caches will dynamically generate content for clients by running code provided by publishers. In the control plane, caches will return logs of client accesses to publishers. In this paper, we introduce Gemini, a system which has both of these capabilities, and discuss two of its key components: security and incremental deployment. Since Gemini caches are deeply involved in content preparation and logging, ensuring that they perform correctly is vital. Traditional end-to-end security mechanisms are not sufficient to protect clients and publishers, so we introduce a new security model which consists of two pieces: an authorization mechanism and a verification mechanism. The former allows a publisher to authorize a set of caches to run its code and serve its content, while the latter allows clients and publishers to probabilistically verify that authorized caches are operating correctly. Because it is unrealistic to assume that Gemini caches will be deployed everywhere simultaneously, we have designed the system to be incrementally deployable and to coexist with legacy clients, caches, and servers. Finally, we describe our implementation of Gemini and present preliminary performance results.