Copay is an easy-to-use, open-source, multiplatform, multisignature, secure bitcoin wallet platform for both individuals and companies. Copay uses Bitcore Wallet Service (BWS) for peer synchronization and network interfacing.

Binary versions of Copay are available for download at Copay.io. Copay Binaries are signed with the key copay@bitpay.com See here for details

Main Features

• Multiple wallet creation and management in-app
• Intuitive, multisignature security for personal or shared wallets
• Easy spending proposal flow for shared wallets and group payments
• BIP32 Hierarchical deterministic (HD) address generation and wallet backups
• Device-based security: all private keys are stored locally, not in the cloud
• Support for Bitcoin testnet wallets
• Synchronous access across all major mobile and desktop platforms
• Payment protocol (BIP70-BIP73) support: easily-identifiable payment requests and verifiable, secure bitcoin payments
• Support for over 150 currency pricing options and unit denomination in BTC or bits
• Email notifications for payments and transfers
• Customizable wallet naming and background colors
• Multiple languages supported
• Available for iOS, Android, Windows Phone, Chrome App, Linux, Windows and OS X devices

Installation

Clone the source:

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.

Note: Other browser extensions could have access to Copay internal data and compromise the user's private key when running Copay as a web page. For optimal security, you should disable all third-party browser extensions when using Copay in this manner.

Build Copay App Bundles

Android

• Install Android SDK
• Run make android

iOS

• Install Xcode 6.1 (or newer)
• Run make ios-prod

Windows Phone

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

Desktop versions (Windows, OS X, 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 nwjs.io
• Run grunt desktop

Google 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 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.

About Copay

General

Copay implements a multisig wallet using p2sh addresses. It supports multiple wallets, each 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. Finally, when 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.

Copay Backups and Recovery

Copay v1.2 use BIP39 mnemonics for backing up wallets. The standard BIP44 is used for wallet address derivation. Multisig wallets uses P2SH address, while non multisig wallets use P2PKH.

Information about Backup and recovery procedures is available at https://github.com/bitpay/copay/blob/master/backupRecovery.md

Previous versions of Copay use files as backups. See the following section.

It is possible to recover funds from a Copay Wallet without using Copay or the Wallet Service, check the Copay Recovery Tool

Wallet Export format

Copay encrypts the backup with the Stanford JS Crypto Library. To extract the private key of your wallet you can use https://bitwiseshiftleft.github.io/sjcl/demo/, copy the backup to 'ciphertext' and enter your password. The resulting JSON will have a key named: xPrivKey, that is the extended private key of your wallet. That information is enough to sign any transaction from your wallet, so be careful when handling it!

The backup also contains the key publicKeyRing that holds the extended public keys of the Copayers. Using a tool like Bitcore PlayGround, and following BIP45 it is possible to generate all wallet address. Note that addresses generated at BWS use the 'shared cosigner index' (2147483647) so Copay address indexes look like: m/45'/2147483647/0/x for main addresses and m/45'/2147483647/1/y for change addresses, where x and y are integers starting from 0. The maximum values of x and y depend on the wallet usage, and in a restore procedure, the generated addresses are scanned on the blockchain for transactions (this is the 'scan' procedure that you can see inside the Copay App settings). To generate the wallet addresses, the required number of Copayers also need to be specified (backup key m).

Bitcore Wallet Service

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

Translations

Copay uses standard gettext PO files for translations and Crowdin as the front-end tool for translators. To join our team of translators, please create an account at Crowdin and translate the Copay documentation and application text into your native language.

To download and build using the latest translations from Crowdin, please use the following commands:

cd i18n
node crowdin_download.js

This will download all partial and complete language translations while also cleaning out any untranslated ones.

Translation Credits:

• Japanese: @dabura667
• French: @kirvx
• Portuguese: @pmichelazzo
• Spanish: @cmgustavo
• German: @saschad
• Russian: @vadim0

Gracias totales!

Release schedules

Copay uses the MAJOR.MINOR.BATCH convention for versioning. Any release that adds features should modify the MINOR or MAJOR number.

Bug Fixing Releases

We release bug fixes as soon as possible for all platforms. Usually around a week after patches, a new release is made with language translation updates (like 1.1.4 and then 1.1.5). There is no coordination so all platforms are updated at the same time.

Minor and Major releases

• t+0: tag the release 1.2 and "text lock" (meaning only non-text related bug fixes. Though this rule is sometimes broken, it's good to make a rule.)
• t+7: testing for 1.2 is finished, translation is also finished, and 1.2.1 is tagged with all translations along with bug fixes made in the last week.
• t+7: iOS is submitted for 1.2.1. All other platforms are submitted with auto-release off.
• t + (~17): All platforms 1.2.1 are released when Apple approves the iOS application update.

How to verify Copay signatures

1. Download copay@bitpay.com public key (gpg --recv-keys 1112CFA1)
2. Download Copay binary ($FILENAME) and signature file ($FILENAME.sig)
3. Check it by running:

$ gpg --verify \
 $FILENAME.sig \
 $FILENAME

# If should say:
 "Good signature from "Copay (visit copay.io) <copay@bitpay.com>"

Public Key for Copay binaries

Instead of importing the public key from a public server (like gnu's) you can grab it from here:

-----BEGIN PGP PUBLIC KEY BLOCK-----
Version: SKS 1.1.5
Comment: Hostname: pgp.mit.edu
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=tKra
-----END PGP PUBLIC KEY BLOCK-----

Save that text to /tmp/key, and then import it as follows:

gpg --import /tmp/key

(Thanks @pzkpfwVI and @mika-mitzahlen for this section, taken from Gist.

Support

• BitPay Labs
  • Post a question in our discussion forums
• GitHub Issues
  • Open an issue if you are having problems with this project
• Email Support
  • Our dedicated support team is always ready to help

License

Copay is released under the MIT License. Please refer to the LICENSE file that accompanies this project for more information including complete terms and conditions.