  Software services are increasingly migrating to the cloud, requiring trust in
actors with direct access to the hardware, software and data comprising the
service. A distributed datastore storing critical data sits at the core of many
services; a prime example being etcd in Kubernetes. Trusted execution
environments can secure this data from cloud providers during execution, but it
is complex to build trustworthy data storage systems using such mechanisms. We
present the design and evaluation of the Ledger-backed Secure Key-Value
datastore (LSKV), a distributed datastore that provides an etcd-like API but
can use trusted execution mechanisms to keep cloud providers outside the trust
boundary. LSKV provides a path to transition traditional systems towards
confidential execution, provides competitive performance compared to etcd, and
helps clients to gain trust in intermediary services. LSKV forms a foundational
core, lowering the barriers to building more trustworthy systems.
