Entros is a proof-of-personhood protocol on Solana, a fast, private, and portable identity layer. As agents come to drive most on-chain activity, a wallet still cannot say whether a person is behind it, and every identity system built so far asks for something permanent like a document, an iris, or a palm print, then checks it once. Entros checks what a snapshot cannot carry. Subtle varitions in Voice, motion and touch inputs, and the temporal coupling between them form a behavioural baseline, and each verification proves the same person returned. The protocol never learns a name, a face or a document, and any Solana program reads the result on chain for free. Live on devnet with three Anchor programs, an open-source SDK and a published research paper. Ahead: a multi-party trusted setup ceremony, an external security audit, mainnet, and a permissionless validator network secured by $ENTROS.