zPass

Anonymous membership for Zcash communities. Prove "I hold a zkSNARK" (or any Zcash-community credential) to unlock chats, votes and perks, without revealing which item, which address or who you are.

• Address-independent passes. Enrol once with a memo challenge. Your pass keeps working when you rotate addresses or change wallets.
• Zero-knowledge proofs in the browser. Semaphore v4 membership proofs with scope-specific nullifiers: one use per poll, chat or app, and no cross-app tracking.
• Zcash-anchored root beacon. Every group root is posted in a shielded memo to a beacon address whose viewing key is public, so anyone can audit the root history and the issuer can't equivocate.
• The issuer can't link usage. The issuer knows who enrolled, but not which member produced which proof. The issuer and verifier databases are separated by role, and the proof hides the leaf.
• Integrations out of the box. Telegram gate bot, anonymous one-vote-per-item polls, "Sign in with zPass", and @zpass/verify for any app in ~15 lines.

Built for the Zecathon Wildcard track (Oct 6–28, 2026).

Status: scaffold. The build follows docs/06-IMPLEMENTATION-PLAN.md.

Architecture

Browser (apps/web: Next.js PWA)
  enrol · identity vault (IndexedDB) · prover (Web Worker) · polls · sign-in · beacon explorer
        │ commitment only        │ proof + scope + message
        ▼                        ▼
  issuer (Hono)             verifier (Hono) ◀── telegram-bot (grammY)
  holder DB, challenges,    proofs, nullifiers,
  members, epochs           polls, OIDC
        │                        ▲
        │ zpass-beacon post      │ zpass-beacon scan (public viewing key)
        ▼                        │
     Zcash: shielded memo  ZP1:<group>:<epoch>:<root>:<size>  ──┘
        │
  Postgres: [issuer schema]   [verifier schema]   (separate roles, no cross-grants)

Details: docs/02-TRD.md §2.6.

Threat model (summary)

Adversary	Protected?	How / caveat
Verifier / app (Telegram, poll)	✅	A proof reveals only "member of group G at root R" + a scope nullifier. No item ID, no address
Issuer (even a malicious one)	✅ for usage, ⚠️ for enrolment	The issuer knows commitment ↔ account at enrolment, but a proof doesn't reveal which commitment was used. Batched epochs + a minimum anonymity set blunt timing attacks
Cross-app tracking	✅	Nullifiers are scope-specific
Double voting / sharing	✅ / ⚠️	Nullifiers prevent double use within a scope. Lending a secret can't be prevented by any credential system
Transfer correlation	⚠️	Leaf changes at sale time are batched per epoch
Root equivocation	✅	Verifiers accept only roots from the public Zcash beacon

Full version: docs/PRODUCT.md.

Repository layout

apps/web/            Next.js 16 PWA: enrol, passes, prover, polls, sign-in, beacon explorer
apps/issuer/         Hono service: holder DB, memo challenges, members, epoch batcher
apps/verifier/       Hono service: /v1/verify, nullifiers, polls, Sign in with zPass
apps/telegram-bot/   grammY gate bot
packages/sdk/        @zpass/sdk: identities, per-item derivation, proving helpers
packages/verify/     @zpass/verify: proof + beacon root + anon set + nullifier checks
packages/db/         Drizzle schema (issuer + verifier), migrations, roles/grants, seed
crates/zpass-beacon/ Rust CLI: post roots, send challenges, scan the beacon
infra/               docker compose (Postgres, Zebra, Zaino, services, Caddy)
docs/                Product description, PRD, TRD, app flow, UI brief, schema, plan

Quickstart (development)

Requirements: Node 22, pnpm 9, Rust 1.89 (via rust-toolchain.toml), Docker.

git clone https://github.com/Udoka-AM/zPass && cd zPass
cp .env.example .env
pnpm install
docker compose -f infra/docker-compose.yml up -d postgres
pnpm db:migrate && pnpm db:seed
pnpm dev   # web on :3000

Checks run in CI:

pnpm lint && pnpm typecheck && pnpm test && pnpm build
cargo fmt --all --check && cargo clippy --workspace --all-targets -- -D warnings && cargo test --workspace

Integrate (preview)

import { verify } from "@zpass/verify";

const result = await verify(proof, {
  group: "zksnarks",
  scopeId: "poll:42",
  scopeHash,
  minAnonSet: 100,
  roots,       // reads roots from the Zcash beacon
  nullifiers,  // your nullifier store
});
if (!result.ok) throw new Error(result.code);

Docs

Product description	PRD
TRD	App flow
UI/UX brief	Backend schema
Implementation plan	Pinned versions

Licence

Dual-licensed under MIT or Apache-2.0, at your option.