PhD Dissertation Proposal: Fadhil Kurnia, Flexible and Secure Replication of Blackbox Stateful Services at the Edge
Content
Speaker:
Abstract:
Edge computing promises to bring stateful services closer to users for lower latency and higher availability, but replicating these services across untrusted and heterogeneous environments remains challenging. Existing replication systems either demand intrusive code changes or provide correctness only under restrictive, expensive strong consistency. This dissertation presents a new foundation for flexible and secure replication of blackbox stateful services at the edge, through three complementary systems: ReFlex, XDN, and OPaxos.
ReFlex introduces a framework for replicating unmodified stateful web services with flexible consistency. It builds on a new abstraction, the Coordinated State Machine (CSM), which models a service as a durable, crash-consistent, request–response module. ReFlex enables developers to choose among diverse consistency levels, ranging from linearizable to eventual consistency, without modifying application code while eliminating sequential execution bottlenecks, efficiently capturing safety-critical state, and enabling reconfiguration of diverse protocols. XDN extends ReFlex to make stateful service distribution practical at the edge. It automatically places replicas across geographically distributed nodes, optimizing for latency, load, and cost under given consistency and availability goals. XDN’s placement optimizer dynamically adjusts consistency policies and replication strategies to match network conditions and workload locality, achieving up to 67% lower average latency than static approaches.
Finally, Oblivious Paxos (OPaxos) and its optimized variant Fast Oblivious Paxos (Fast OPaxos) address privacy and security in replication across untrusted infrastructure. These protocols combine consensus with secret sharing to ensure that replicas can agree on state updates without revealing sensitive data. This allows strongly consistent replication even when some nodes are only semi-trusted, achieving high throughput with minimal cryptographic overhead. Together, these three systems form a cohesive architecture for flexible, efficient, and privacy-preserving replication of blackbox stateful services at the edge. The dissertation advances the state of the art in edge computing by reconciling flexibility, performance, and security, bringing us closer to a world where stateful services can be deployed and replicated as effortlessly as static content in conventional Content Delivery Networks (CDNs).
Advisor:
Arun Venkataramani