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Carousel scores a billion encrypted vectors without client index state

Original title: CAROUSEL: GPU-Accelerated Private Vector Search via Homomorphic Sketching

arXiv cs.CRby Sohaib ()1 min read
AI summary · x-ai/grok-4.7Summaries by Vani AI

On BIGANN SIFT1B it reports recall@100 of 0.9715; 100 million vectors take 3.735 seconds on one GPU.

Carousel is a homomorphic private vector-search design that scores the full corpus under encryption and compresses results for client-side ranking. The server raises encrypted scores to a power that preserves order and suppresses most values, then packs the sparse result with homomorphic additions. The paper says clients hold no database-dependent state, so inserts and deletes apply after one vector write, and reports no recall loss from discarding candidates.

Key facts
  • It searches 1 billion BIGANN SIFT1B vectors across multiple GPUs.
  • Recall@100 is 0.9715 on that billion-vector corpus.
  • At 100 million SIFT vectors, recall@100 is 0.9845.
  • That smaller search takes 3.735 seconds on a single GPU.
  • Compression uses homomorphic additions into a logarithmic number of ciphertexts.
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From the original article

1 min read at arxiv.org

Vector search on untrusted infrastructure exposes the \emph{query embedding}, a faithful summary of the user's intent. Fully homomorphic encryption can hide the query, but existing approaches still require a full scan followed by ranking of encrypted scores.

arXiv cs.CR

By Sohaib · arxiv.org

Read the full article at arXiv cs.CR

A short excerpt; the article and its images belong to the publisher. Summary, key facts and assessment above are AI-written from the article and can be wrong.