@kashscript/identity-zkp

Zero-knowledge primitives for did:kash. Selective disclosure via Merkle commitments + a Web-Worker-dispatched prover/verifier for Groth16 / PLONK circuits.

⚠ Partial Schedule B. The Merkle / selective-disclosure layer is permissive. The SNARK prover is a Commercial component requiring a paid Plan for Production Use. See LICENSE.

bun add @kashscript/identity-zkp @kashscript/identity-core
# optional: snarkjs as a peer dep for the prover
bun add snarkjs

Two layers, two licences

| Layer | Licence | Purpose | |---------------------------------|---------------|------------------------------------------------------| | Selective disclosure (Merkle) | Permissive | Prove one field of a DID Document without revealing the rest | | SNARK prover (Groth16 / PLONK) | Commercial | Generate succinct proofs of arbitrary predicates over identity data |

Most apps need only the Merkle layer; the SNARK prover is for compliance attestations, age-gating, KYC-once-prove-many flows, and similar high-assurance use cases.

Quickstart — selective disclosure

import { commitDocument, openCommitment } from "@kashscript/identity-zkp/disclosure";

// Holder: commit to the full DID Document, share only the commitment
const commitment = commitDocument(myDidDocument);

// Verifier: ask for a specific field
const proof = openCommitment(myDidDocument, commitment, ["country"]);

// Verifier: verify just that field
const ok = verifyOpening(commitment, proof);   // true iff country was in the original doc

The verifier learns only the requested field + a proof of inclusion in the original document — nothing about any other field.

Quickstart — SNARK proving (Commercial)

import { Worker } from "node:worker_threads";
import { ProverClient } from "@kashscript/identity-zkp/prover";

const prover = new ProverClient({
  worker: new Worker(new URL("@kashscript/identity-zkp/worker", import.meta.url)),
});

const proof = await prover.prove("age-over-18", { dob: "1992-05-14" });

The worker dispatch is mandatory: SNARK proving is CPU-expensive and must not block the main thread. The worker uses snarkjs under the hood (peer dep, optional install).

What's in the box

| Subpath | Purpose | |----------------------------------------|----------------------------------------------------| | @kashscript/identity-zkp | Default — re-exports Merkle + prover | | @kashscript/identity-zkp/merkle | Merkle tree primitives | | @kashscript/identity-zkp/disclosure | Selective-disclosure commit / open / verify | | @kashscript/identity-zkp/prover | SNARK prover client (Commercial) | | @kashscript/identity-zkp/verifier | SNARK verifier — permissive | | @kashscript/identity-zkp/worker | Web-Worker entry point for the prover | | @kashscript/identity-zkp/circuits | Bundled circuits (age-over-18, country-in-set, …) | | @kashscript/identity-zkp/errors | Typed error classes |

Licensing

See LICENSE. The licence file inlines the SSLA Schedule B terms that apply to the SNARK prover. The Merkle layer is at-least-as- permissive as Apache-2.0.