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Sameer Wagh — privacy researcher and founder of SecretBit Ventures. Applied cryptography, secure computation, and privacy-preserving machine learning.

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Latest posts

Coin Parity with a Balance Scale

You have 2ⁿ visually identical coins, each weighing 0 or 1 gram. In at most n weighings on a balance scale, you can always determine whether the count of zero-weight coins is even or odd. The key is a binary search over a swap path.

A novel method for input privacy from LLMs

The Stained Glass Transform is a transformer-based network trained to scramble token embeddings while preserving their utility under LLM inference. The output is somewhat magical: the model still produces coherent output but the original prompt is unrecoverable.

Can an LLM solve this combinatorics problem?

Sixteen cards, four binary properties, and an LLM agent left alone with a machine and its weekends -- chasing D(16), the fewest probes that always pin down a hidden arrangement. It walked the best-known strategy down 64 → 60 → 49 → 47 → 46, one probe above the information floor, where an old ghost from sorting is waiting.

Do the math where it’s easy

Fast private lookup tables, explained through one idea you already know — Parseval's theorem. A dot product is the same in the signal domain and the wavelet domain, so compute it wherever it's cheapest.

Secure enclaves for AI evaluation

Evaluating a frontier model on sensitive data when neither side wants to trust the other — work with Anthropic and the UK AI Safety Institute, on the OpenMined blog.

Should we swap numbers? A secret way to find out

Using card-based cryptography to show how two people can compute the AND of their private answers using nothing but a handful of playing cards, and why that little trick is the seed of an entire field called secure multiparty computation.

Training a neural network in the dark

Piranha was the first to train a neural network end-to-end under secure computation. The hard part wasn't speed — it was knowing why a run failed when you can't see a single value.

Schwartz–Zippel over rings and open conjectures

The Schwartz–Zippel lemma is the workhorse behind countless protocols — over fields. Pika carries it to rings, where zero divisors get in the way, and leaves a crisp open question: how small can the slack constant be?

Why private AI belongs on a GPU

For years, secure multi-party computation chased fewer rounds of communication. FALCON asked what happens at ML scale — and the answer flips the optimization target from network to silicon.

+ and × is all you need

Private ML normally juggles two secret-sharing types — arithmetic for linear layers, Boolean for the rest — bridged by a costly conversion. SecureNN does the hard parts with just + and ×, and skips the bridge entirely.