Is there a human behind this GitHub account?

passportsign answers that, cryptographically, without revealing who.

A maintainer scans their passport with the ZKPassport mobile app and proves the chip is genuine. They prove control of a GitHub account by publishing a one-time nonce in a public gist. The resulting attestation lands in the public Sigstore Rekor transparency log as an in-toto statement with predicate type https://passportsign.dev/personhood/v1. Anyone — skeptic, bot, employer, downstream consumer — can re-verify it from scratch, with no need to trust passportsign.dev itself.

It is Sigstore-adjacent, in the same way that gitsign is. gitsign signs Git commits with OIDC identity and logs to Rekor — but it doesn’t establish personhood. An AI agent with a GitHub account passes gitsign trivially. passportsign fills that gap.

See it live

The first real-passport bind, shipped 2026-05-25:

passportsign verified · CAN · 2026-05-25

Binds @cynarlab — the maintainer of debugmcp/mcp-debugger — to a passport-holding human, disclosing only Canadian citizenship. Click through to read the entry on Rekor; nothing about who they are beyond that ever touches a server.

What the badge claims, and what it doesn’t

The full claim, no more:

At time T, a human holding a valid government-issued passport (and optionally: a citizen of country X, if the subject chose to disclose) was in control of the GitHub account @username.

The badge does not claim:

Overclaiming is the failure mode that kills trust services. The badge is evidence for an accountability claim plus optional attested attributes, not a substitute for any broader judgement. See the spec §1 for the full statement and §8 for the explicit Sybil-resistance limits.

Try it

You’ll need Node 22+, the ZKPassport mobile app (or Android) with an NFC e-passport loaded, and a GitHub account you can create a public gist on.

git clone https://github.com/debugmcp/passportsign.git
cd passportsign
pnpm install
pnpm --filter @passportsign/cli exec tsx src/index.ts bind <your-github-username> --country

The CLI walks four steps — gist → QR scan → Rekor submit → bundle & badge written to your working directory. Detailed flow in the repo README.

Verify someone else’s binding

pnpm --filter @passportsign/cli exec tsx src/index.ts verify ./binding.passportsign.json

Four checks, zero dependency on a passportsign.dev operator:

  1. The statement bytes hash to the Rekor entry’s recorded payloadHash.
  2. The Merkle inclusion proof verifies against the captured root.
  3. The captured root is consistent with the current witnessed root (no log rewrite that orphans the entry).
  4. The zkPassport SDK accepts the proof, and the unique identifier it produces matches the statement.

--no-rekor-refetch skips the online checks for purely offline verification; --gist-recheck adds a liveness signal by re-fetching the captured gist URL.

How it works

Layer What it does Who provides it
zkPassport SDK Generates and verifies the zero-knowledge proof from the passport’s NFC chip docs.zkpassport.id
GitHub gist One-time nonce posted publicly under the bound username, proving GitHub-side control github.com
in-toto statement Canonical attestation: the gist + proof + scope + (optional) disclosed country in-toto.io
Sigstore Rekor Append-only, witnessed, transparency log — the trust anchor docs.sigstore.dev
passportsign Glues the four together; ships the CLI + verifier this project

The skeptic’s full re-derivation: fetch the entry from public Rekor, run the zkPassport SDK on the embedded proof, re-hash the statement, walk the Merkle path. No passportsign-controlled service required at any step.

Status & roadmap

Version Scope Status
v0 CLI proof-of-concept: bind, verify, badge generation shipped 2026-05-25
v1 Next.js web app: hosted badge service at passportsign.dev/badge/<user>.svg, /verify/<user> static verifier, REST API planned (~3–4 weeks)
v1.5 Slack/Discord bot mention-resolvers, federated operators, reference standalone verifier CLI planned
v2 Federated operators, org-level bindings, additional witness recruitment planned

The full v0 acceptance walkthrough — six criteria, all PASS or deliberately deferred to v1 — is in docs/v0-acceptance.md.

Why this exists

It was built to answer one specific question, asked publicly on debugmcp/mcp-debugger#77: “Who are the key humans behind debugmcp and mcp-debugger?”. The maintainer wrote passportsign and bound their own GitHub account to a passport-holding human as the response. That whole chain — question → product → response — is public and verifiable.

Source & links