Zero-Knowledge AI Matching: Binarized Embeddings + Hamming Distance

Part 3 of a series on building a privacy-first dating platform for HIV-positive communities. Building a Zero-Knowledge Dating Platform for HIV-Positive Communities covers the architecture. Matching in the Dark: Zero‑Knowledge Filtering Using 32‑Bit Bitmasks covers bitmask filtering. Bitmasks got us far. Two people can match on gender, region, marital status, and relationship intent — all without the server understanding any of it. That's the hard filter layer, and it works beautifully. But here's what bitmasks can't tell you: whether two people will actually connect. Someone can check every categorical box and still be a terrible match. The things that create real compatibility — how someone writes about themselves, what they care about, how they think about life — are too rich, too nuanced, too human to reduce to a set of switches. So how do you compute soft compatibility when the server isn't allowed to read a single word of anyone's profile? This is the second half of the matching e