Harpocrates: Giving Out Your Secrets and Keeping Them Too
Proceedings of The Third ACM/IEEE Symposium on Edge Computing (SEC) 2018.
Content Distribution Networks (CDNs) offer websites and web services the ability to host content on servers that are near the edge of the network, close to users. Benefits of this arrangement include low latency, scalability, and resistance to Denial of Service attacks. Traditionally, CDNs have hosted primarily static content, but increasingly, there is an interest in pushing active computation to the edge as well. This active computation, which is similar in style to the "serverless" computing becoming popular in clouds, offers a wealth of new opportunities for web services to become faster and more scalable. With this opportunity, however, comes a much greater exposure to security threats. One is leakage of secret materials (such as keys, identities, etc.) that are accessed by these functions. Another is the possibility that sensitive calculations are not executed faithfully in the CDN; e.g. a modified version of the customer's code is run.