Anthropic Unveils FlashProve for Proving Which Model Answered You

The research prototype proves about 110 tokens per second on a 400B-parameter model, using the same family of hash-based proofs behind Ethereum's ZK rollups. Anthropic's Frontier Red Team released FlashProve , an Apache-licensed library that lets an AI provider cryptographically prove a response came from a specific set of model weights, without revealing the weights. It leans on the same family of hash-based proofs that power Ethereum L2s like Starknet. The problem: When you query an AI API, you can't tell whether the model you paid for actually answered, or whether a router quietly swapped in a cheaper one.