@cryptkeeperzk/semaphore-proof

Semaphore proof

A library to generate and verify Semaphore proofs.

👥 Contributing   |   🤝 Code of conduct   |   🔎 Issues   |   🗣️ Chat & Support

This library provides utility functions to generate and verify Semaphore proofs compatible with the Semaphore circuits. Generating valid zero-knowledge proofs requires files that can only be obtained in an attested trusted-setup ceremony. For a complete list of ready-to-use files visit trusted-setup-pse.org.

🛠 Install

npm or yarn

Install the @cryptkeeperzk/semaphore-proof package and its peer dependencies with npm:

npm i @cryptkeeperzk/semaphore-identity@cryptkeeperzk/semaphore-group @cryptkeeperzk/semaphore-proof

or yarn:

yarn add @cryptkeeperzk/semaphore-identity@cryptkeeperzk/semaphore-group @cryptkeeperzk/semaphore-proof

📜 Usage

# generateProof( identity: Identity, group: Group | MerkleProof, externalNullifier: BytesLike | Hexable | number | bigint, signal: BytesLike | Hexable | number | bigint, snarkArtifacts?: SnarkArtifacts ): Promise<SemaphoreFullProof>

import { Identity } from "@cryptkeeperzk/semaphore-identity"
import { Group } from "@cryptkeeperzk/semaphore-group"
import { generateProof } from "@cryptkeeperzk/semaphore-proof"
import { utils } from "ethers"

const identity = new Identity()
const group = new Group()
const externalNullifier = utils.formatBytes32String("Topic")
const signal = utils.formatBytes32String("Hello world")

group.addMembers([...identityCommitments, identity.generateCommitment()])

const fullProof = await generateProof(identity, group, externalNullifier, signal, {
    zkeyFilePath: "./semaphore.zkey",
    wasmFilePath: "./semaphore.wasm"
})

// You can also use the default zkey/wasm files (it only works from browsers!).
// const fullProof = await generateProof(identity, group, externalNullifier, signal)

# verifyProof(fullProof: FullProof, treeDepth: number): Promise<boolean>

import { verifyProof } from "@cryptkeeperzk/semaphore-proof"

await verifyProof(fullProof, 20)

# calculateNullifierHash( identityNullifier: bigint | number | string, externalNullifier: _BytesLike | Hexable | number | bigint ): bigint

import { Identity } from "@cryptkeeperzk/semaphore-identity"
import { calculateNullifierHash } from "@cryptkeeperzk/semaphore-proof"

const identity = new Identity()
const externalNullifier = utils.formatBytes32String("Topic")

const nullifierHash = calculateNullifierHash(identity.nullifier, externalNullifier)