> Plain-language definitions: Know Your Agent (KYA), agent KYC, zero-knowledge presentations, reusable KYC, holder binding, x402, Web Bot Auth and the MintID network roles. Glossary # The vocabulary of verifiable agent identity Fourteen terms, defined the way the protocol uses them. Each entry is self-contained: what the term means, why it exists, and how MintID implements it. Link to any definition directly with its anchor. [§](#know-your-agent)Know Your Agent (KYA) Know Your Agent (KYA) is the practice of verifying that an autonomous AI agent is operated by a known, accountable party — the agent-era counterpart to Know Your Customer (KYC). A KYA check answers one question before an agent is allowed to transact: if this agent causes harm, is there a real, liable human or organisation behind it? MintID implements KYA with zero-knowledge credentials, so the answer is provable without revealing who that human is. [§](#agent-kyc)Agent KYC Agent KYC is MintID’s protocol-level implementation of Know Your Agent: an AI agent carries a credential derived from its operator’s real KYC, issued by an approved issuer, and proves with a zero-knowledge presentation that an accountable, KYC-verified human backs it — without disclosing the human’s identity. It is specified in SPEC-2 and works on the same rail as human credentials. [§](#zero-knowledge-kya)Zero-knowledge KYA · privacy-preserving KYA Zero-knowledge KYA (privacy-preserving Know Your Agent) is agent verification where the counterparty learns exactly one bit — "this agent is backed by an accountable, KYC-verified principal" — and nothing else: no name, no passport, no persistent handle that tracks the operator across services. It resolves the accountability-versus-privacy binary that plaintext agent registries and transferable agent NFTs cannot: accountability exists, surveillance does not. [§](#zero-knowledge-presentation)Zero-knowledge presentation A zero-knowledge presentation is a cryptographic proof, generated by a credential holder, that convinces a verifier a claim is true (over 18, valid credential, agent backed by a verified human) without revealing the underlying data or creating a linkable identifier. In MintID, presentations are bound to the verifier’s challenge, expire in about ten seconds, and are never logged on-chain. [§](#reusable-kyc)Reusable KYC Reusable KYC means completing identity verification once, with an approved issuer, and then proving facts from it anywhere, any number of times, without repeating the check or re-exposing documents. One verification backs many proofs — and, through agent credentials, many agents. It replaces the per-service KYC cycle, where every counterparty re-collects and re-stores the same passports and selfies. [§](#verifiable-credential)Verifiable credential A verifiable credential is a digitally signed attestation — an issuer vouching that facts about a subject are true — that third parties can check cryptographically without contacting the issuer. In MintID, credentials live with the holder (never on-chain), and what circulates are zero-knowledge presentations derived from them. [§](#anonymous-credential)Anonymous credential An anonymous credential is a verifiable credential designed so that using it does not identify the holder: each presentation is unlinkable to previous ones and to the issuance event. The verifier learns the proven claim and nothing else. This is the cryptographic primitive (BBS-family signatures and successors) that lets accountability and privacy coexist. [§](#selective-disclosure)Selective disclosure Selective disclosure is revealing only the specific attributes a transaction needs — an age bound, an assurance grade, a spending limit — while keeping every other attribute of the credential hidden. MintID applies it to authorisation too: an agent’s scope is proven axis by axis, so a merchant learns the limit that matters, not the whole mandate. [§](#holder-binding)Holder binding Holder binding is the cryptographic link between a credential and the only key that can use it. The holder keeps that private key; issuers cannot use the credential on the holder’s behalf, and a stolen credential file is useless without the key. In MintID, agent credentials are additionally bound to their controlling principal’s credential, forming an auditable chain of accountability. [§](#issuer)Issuer An issuer is an approved KYC organisation that verifies people once, off-chain, and then issues reusable credentials to them. MintID issuers publish signed status roots, lock a slashable bond as skin in the game, and never see where holders later present their credentials. The chain records issuer approvals and status roots — never the KYC files. [§](#verifier)Verifier A verifier is any service — an exchange, a marketplace, an API, a merchant checkout — that requests a zero-knowledge presentation before acting. Verifiers check a ten-second proof against the issuer’s published status root, keep a minimal decision record, and never receive, store or forward personal data. Integration is through the MintID verifier SDKs. [§](#validator)Validator A validator is a node operator staking on MintID’s permissionless proof-of-stake consensus (CometBFT). Validators order transactions and check cryptographic evidence — signatures, bonds, status roots. They never process passports, biometrics or KYC files, because none of that ever touches the chain. [§](#status-root)Status root A status root is a small cryptographic commitment an issuer publishes on-chain that summarises the validity state of every credential it has issued — without listing them. A presentation proves membership of the current root in zero knowledge, so revocation works (including holder self-revocation) while the chain learns nothing about individual credentials. [§](#x402)x402 x402 is an open payment protocol that puts the dormant HTTP 402 "Payment Required" status to work: a server quotes a price in the 402 response, the client pays (typically in stablecoins, wallet to wallet), and retries with proof of payment. It is the settlement rail of the emerging pay-per-use agentic web — including Cloudflare’s Monetization Gateway — and it prices requests without identifying buyers, which is exactly the gap zero-knowledge KYA fills when a seller needs accountability too. [§](#mcp)Model Context Protocol (MCP) The Model Context Protocol (MCP) is an open protocol by which an AI agent discovers and calls external capabilities as "tools" — a uniform listing-and-invocation surface that agent frameworks speak natively. It is becoming the consumption unit of the agentic web, which is why identity verification has to be reachable as a tool: MintID publishes an MCP server that exposes the three operations of its frozen verifier-service contract, run inside the verifier’s own perimeter against the verifier’s own service. [§](#web-bot-auth)Web Bot Auth Web Bot Auth is an emerging IETF standard (built on HTTP Message Signatures, RFC 9421) by which a bot or agent cryptographically signs its requests so origins can verify which operator is calling. It authenticates the agent’s software identity — this is Anthropic’s or OpenAI’s crawler. It does not, by itself, say anything about the accountability of the principal behind an autonomous agent; that is the layer KYA credentials add. ## See the vocabulary at work Agent KYC is the protocol’s home for these ideas: how an AI agent proves an accountable human stands behind it — in zero knowledge, on a sovereign Layer-1. [Agent KYC, explained](/en/agent-kyc)[What is Know Your Agent?](/en/blog/what-is-know-your-agent) --- Source: https://mintid.net/en/glossary · Glossary — Know Your Agent (KYA) & zero-knowledge identity terms — MintID