CODEX (COrnell Data EXchange) stores secrets for subsequent access by authorized clients. It also is a vehicle for exploring the generality of a relatively new approach to building distributed services that are both fault-tolerant and attack-tolerant. Elements of that approach include: embracing the asynchronous (rather than synchronous) model of computation, use of Byzantine quorum systems for storing state, and employing proactive secret sharing with threshold cryptography for implementing confidentiality and authentication of service responses. Besides explaining the CODEX protocols, experiments to measure their performance are discussed.