Copay is an easy-to-use, open-source, multiplatform, multisignature, secure bitcoin wallet platform for both individuals and companies.

Copay uses Bitcore-Wallet-Service (https://github.com/bitpay/bitcore-wallet-service) for peer synchronization and bitcore network interfacing.

Binary versions of Copay are available for download at Copay.io

Installation

Bitcore Wallet Service

Copay depends on Bitcore Wallet Service (BWS) for blockchain information, networking and copayer synchronization. BWS can be run within minutes or you can use a public instance. Switch between BWS instances is very simple and can be done with a click from Copay. BWS also allows Copay to interoperate with others wallet like Bitcore-Wallet CLI https://github.com/bitpay/bitcore-wallet.

Alternativelly, public BWS instances (like https://bws.bitpay.com) can be used.

Copay 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
npm start

Then visit localhost:3000 in your browser.

When running Copay as a web page, and a browser extension is enabled, the browser extension could have access to Copay internal data, and compromise the user's private key and more.

Build Copay App Bundles

Android

• Install Android SDK
• Run make android

iOS

• Install XCode
• Run make ios-prod

Windows Phone

• Install Visual Studio 2013 (or newer)
• Run make wp8-prod

Desktop versions (Windows, OSX, Linux)

Copay uses NW.js (also know as node-webkit) for its desktop version. NW.js an app runtime based on Chromium and node.js.

• Install NW.js in your system from nw.js
• Run grunt desktop (*)

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.

Translations

Copay uses standart gettext PO files for tranlations. It is currently translated to spanish, japanese, french, german and portuguese thank to community contributions. See https://github.com/bitpay/copay/pull/2880 as an example pull request for adding translations.

Translation Credits: Japanese: @dabura667, French: @kirvx, Portuguese: @pmichelazzo, Spanish: @cmgustavo, German: @saschad. Gracias totales!

About Copay

General

Copay implements a multisig wallet using p2sh addresses. It supports multiple wallet, with with its own configuration, 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 extended 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.

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.

Bitcore

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

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 customer to the server are not supported (i.e. there is no place to write messages to the server in the current UX)