Anthropic Releases FlashProve for Cryptographic AI Inference Proofs

Anthropic released FlashProve on November 2, 2026: an open-source research prototype that uses cryptographic proofs to show a language-model response came from committed weights without revealing them. The company reported proof generation at 110 tokens per second for Meta’s Llama 4 Maverick. The work addresses a verification gap in hosted AI. A high-quality answer does not establish which model produced it: a routing service could substitute another system, an evaluator could receive a different model from the one intended for testing, or an attacker could alter the token stream.

Checking by rerunning the model is impractical for users when weights are private and the hardware requirements are substantial. FlashProve uses a zero-knowledge succinct argument of knowledge, or zkSNARK, in a software-only design rather than depending on trusted hardware. During an offline phase, the provider publishes a short commitment that identifies one exact set of weights while keeping them secret.

For completed prompt-and-response pairs, the system produces a proof that the output tokens are the committed model’s output. Anyone holding the commitment, prompt and reply can check the proof without access…