Addra: Metadata-private voice communication over fully untrusted infrastructure
Talkat 15th USENIX Symposium on Operating Systems Design and Implementation (OSDI '21) · 2021-07-14..07-16·
summary
Addra implements a mailbox architecture where senders deposit outgoing packets to a fixed mailbox and receivers retrieve them with two-hop mailbox assignment, breaking sender–receiver links while tolerating compromise of routers, switches, or servers. It builds a new PIR called FastPIR (homomorphic batching plus optimized rotations) and runs on an 80-node AWS cluster, scaling to 32K users with 99th-percentile message latency 726 ms—about 7× faster than the best prior system in the same threat model.
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chapters (9)
- 0:00Introduction
- 1:43Metadata
- 4:45Challenges
- 6:07Private Information Retrieval
- 7:01Architecture
- 8:46Advantages
- 9:39Scaling
- 13:58Performance comparison
- 14:37Summary
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