Copay is an easy-to-use, open-source, multiplatform, multisignature, secure bitcoin wallet platform for both individuals and companies. With Copay, now everyone using bitcoin can enjoy a wallet with corporate-level security!

When friends or company executives join a Copay wallet, more than one person must sign every transaction. If your computer is ever compromised and your private keys are stolen, the bitcoins are still safe if you used the multi-signature feature. This feature is in addition to state-of-the-art encrypted storage and communication.

Before you start

Note: Please check the Copay Known Issues before using Copay with real Bitcoins.

Installation

git clone https://github.com/bitpay/copay.git
cd copay

Install bower and grunt if you haven't already:

npm install -g bower
npm install -g grunt-cli

Build Copay:

bower install
npm install
grunt

For production environments:

grunt prod

Open Copay:

npm start

Then visit localhost:3000 in your browser.

Tests

Open test/index.html in your browser to test models. Install mocha and karma to test the services and controllers.

npm install mocha
npm install karma-cli

Run all tests:

mocha
karma start

Configuration

The default configuration can be found in the config.js file - see config.js for more info. This configuration could be partially overridden with the options set at the "Settings" tab.

Troubleshooting

Building on Ubuntu 14.04, gyp, Python

If you are using Ubuntu and encounter this error (or one similar):

gyp_main.py: error: no such option: --no-parallel
gyp ERR! configure error 
gyp ERR! stack Error: `gyp` failed with exit code: 2

This is because Ubuntu 14.04 and 14.10 have Python 2.7 installed by default but gyp requires Python 2.6. See: (http://stackoverflow.com/questions/21155922/error-installing-node-gyp-on-ubuntu)

One solution to this issue is to use Copay with a Python version manager and install 2.6. For example, if you have pyenv installed:

pyenv install 2.6.9
pyenv global 2.6.9

Development

Google Chrome App

To build Copay's Chrome App, run:

npm run-script chrome

On success, the chrome extension will be located at: browser-extensions/chrome/copay-chrome-extension

To install it go to chrome://extensions/ in your Chrome browser and ensure you have the 'developer mode' option enabled in the settings. Then click on "Load unpacked chrome extension" and choose the directory mentioned above.

Firefox Add-on

The CoPay Firefox Extension has been deprecated and is no longer supported.

QA and Bug Reporting

In the interest of improving bug reporting, for each bug that you find and want to create a ticket about, please refer to a form that contains:

• A brief description of the bug
• Steps required to reproduce it
• The platform in which you are testing
• Any screenshots, if possible
• The expected behaviour

For example, a really useful bug report should look like:

Problem: The application fails at login.

To reproduce:
1. Launch the app with `npm run start`
2. Click on "Join a Wallet"
3. Type an nonexistent username
4. The app stops working and throws an "Unhandled exception" error.

Expected: The app should login to the home screen after clicking login and show no errors.

Platform: Android 4.3, Android 4.4, iOS

About Copay

General

Copay implements a multisig wallet using p2sh addresses. It supports multiple wallet configurations, such as 3-of-5 (3 required signatures from 5 participant peers) or 2-of-3. To create a multisig wallet shared between multiple participants, Copay requires the public keys of all the wallet participants. Those public keys are then incorporated into the wallet configuration and combined to generate a payment address where funds can be sent into the wallet. Conversely, each participant manages their own private key and that private key is never transmitted anywhere.

To unlock a payment and spend the wallet's funds, a quorum of participant signatures must be collected and assembled in the transaction. The funds cannot be spent without at least the minimum number of signatures required by the wallet configuration (2 of 3, 3 of 5, 6 of 6, etc). Once a transaction proposal is created, the proposal is distributed among the wallet participants for each to sign the transaction locally. Once the transaction is signed, the last signing participant will broadcast the transaction to the Bitcoin network using a public API (defaults to the Insight API).

Copay also implements BIP32 to generate new addresses for peers. The public key that each participant contributes to the wallet is a BIP32 extended public key. As additional public keys are needed for wallet operations (to produce new addresses to receive payments into the wallet, for example) new public keys can be derived from the participants' original extended public keys. Once again, it's important to stress that each participant keeps their own private keys locally - private keys are not shared - and are used to sign transaction proposals to make payments from the shared wallet.

For more information regarding how addresses are generated using this procedure, see: Structure for Deterministic P2SH Multisignature Wallets.

Security model

Copay peers encrypt and sign each message using the hybrid Elliptic Curve Integrated Encryption Scheme (ECIES).

The identity key is an ECDSA public key derived from the participant's extended public key using a specific BIP32 branch. This special public key is never used for Bitcoin address creation and should only be known by members of the WR. In Copay this special public key is named copayerId. A hash of the copayerId named peerId is used to register with a peerjs server. For more information on this hash value, please refer to the Bitcoin Wiki page entitled Identity protocol v1.

Registering with a hash avoids disclosing the copayerId to parties outside of the WR. Peer discovery is accomplished using only the hashes of the WR members' copayerIds. All members of the WR know the full copayerId's of all the other members of the WR.

Bitcore

Copay uses the powerful and feature-rich Bitcore Javascript library for Bitcoin-related functions. Bitcore should be built this way:

var cmd = `node util/build_bitcore.js`
cd <BITCORE_HOME>
node $cmd

Payment Protocol

Copay currently supports BIP70 (Payment Protocol), with the following limitations:

• Only one output is allowed. Payment requests that are more that one output are not supported.
• Only standard Pay-to-pubkeyhash and Pay-to-scripthash scripts are supported (on payment requests). Other script types will cause the entire payment request to be rejected.
• Memos from the custormer to the server are not supported (i.e. there is no place to write messages to the server in the current UX)