Semaphore

Semaphore is a zero-knowledge gadget which allows users to prove their membership of a set without revealing their original identity. At the same time, it allows users to signal their endorsement of an arbitrary string. It is designed to be a simple and generic privacy layer for Ethereum dApps. Use cases include private voting, whistleblowing, mixers, and anonymous authentication.

For more information, refer to the documentation.

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Quick start

Semaphore has been tested with Node 11.14.0. It will run with Node 12 LTE but we highly recommend using Node 11.14.0 if you wish to develop on its source code, as one of its dependencies, script, cannot compile when if you use Node 12.

Use nvm to manage your Node version.

Clone this repository, install dependencies, and build the source code:

git clone git@github.com:kobigurk/semaphore.git && \
cd semaphore && \
npm i && \
npm run bootstrap && \
npm run build

Note: we use lerna to manage the circuits, config, and contracts subpackages. Do not run npm install within any of these directories. Instead, just run npm run bootstrap in the main directory.

Next, either download the compiled zk-SNARK circuit, proving key, and verification key (note that these keys are for testing purposes, and not for production, as there is no certainty that the toxic waste was securely discarded).

To download the circuit, proving key, and verification key, run:

# Start from the base directory

./circuits/scripts/download_snarks.sh

To generate the above files locally instead, run:

# Start from the base directory

./circuits/scripts/build_snarks.sh

This process should take about 45 minutes.

Build the Solidity contracts:

# Start from the base directory

cd contracts && \
npm run compileSol

Run tests while still in the contracts/ directory:

# Open another terminal and start Ganache
npm run ganache

# The first command tests the Merkle tree contract and the second
# tests the Semaphore contract

npm run test-semaphore && \
npm run test-mt

Rinkeby

Semaphore Base: 0x17f99103f31Ff357ad59e28BF445b985b3Db5D29 Semaphore Voting Base: 0x0e7376E92A9326Fc1c290c89d6D998dFAf94F45c Wallet Base: 0x5599CF80A76eC5a34628e0c605a194152952F4d8 Proxy Factory: 0x17B77172270f0c74853c0a2bC12687E47D3eE156