Anthropic releases FlashProve, an open-source zkSNARK system for provable LLM inference

Anthropic released FlashProve, an open-source prototype that uses zkSNARKs to prove a response came from a committed model without revealing its weights. On Llama 4 Maverick (400B-parameter MoE, 4-bit weights), a single H100 generates proofs at about 110 tokens/second with ~19 MB proofs per 1,024-token request, roughly 70-95x the GPU time vLLM needs for the same work. The release includes executable prover and verifier code, a C++ fast verifier, a Lean verifier with machine-checked completeness, soundness and zero-knowledge statements, and a technical report, all under Apache 2.0.