FcashApp is a secure bitcoin wallet platform for both desktop and mobile devices. FcashApp uses Fcash Wallet Service (FWS) for peer synchronization and network interfacing.

Binary versions of FcashApp are available for download at Fcash.cash. FcashApp Binaries are signed with the key [email protected] – See the section How to Verify FcashApp Signatures for details.

This project was created by Fcash Inc, and it is maintained by Fcash and houndreds of contributors. There is a Fcash branded version of FcashApp at mobile phone stores, Fcash Wallet, which features integration with the Fcash Visa Debit Card, as its main difference.

For a list of frequently asked questions please visit the FcashApp FAQ.

Main Features

• Fcash and Fcash Cash coin support
• 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 Fcash 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
• Mnemonic (BIP39) support for wallet backups
• Paper wallet sweep support (BIP38)
• Email notifications for payments and transfers
• Push notifications (only available for ios and android versions)
• Customizable wallet naming and background colors
• Multiple languages supported
• Available for iOS, Android, Windows Phone, Chrome App, Linux, Windows and OS X devices

Testing in a Browser

Note: This method should only be used for development purposes. When running FcashApp in a normal browser environment, browser extensions and other malicious code might have access to internal data and private keys. For production use, see the latest official releases.

Clone the repo and open the directory:

git https://github.com/fcash-js/fcashpay.git
cd fcashpay

Ensure you have Node installed, then install and start FcashApp:

npm install
npm run apply:fcashpay
npm run start

Visit localhost:8100 to view the app.

Unit & E2E Tests (Karma & Protractor)

To run the tests, run:

 npm run test

Testing on Real Devices

It's recommended that all final testing be done on a real device – both to assess performance and to enable features that are unavailable to the emulator (e.g. a device camera).

Android

Follow the Cordova Android Platform Guide to set up your development environment.

When your developement enviroment is ready, run the start:android package script.

npm run apply:fcashpay
npm run prepare:fcashpay
npm run start:android

iOS

Follow the Cordova iOS Platform Guide to set up your development environment.

When your developement enviroment is ready, run the start:ios package script.

npm run apply:fcashpay
npm run prepare:fcashpay
npm run start:ios

Build FcashApp App Bundles

Before building the release version for a platform, run the clean-all command to delete any untracked files in your current working directory. (Be sure to stash any uncommited changes you've made.) This guarantees consistency across builds for the current state of this repository.

The final commands build the production version of the app, and bundle it with the release version of the platform being built.

Android

npm run clean-all
npm run apply:fcashpay
npm run prepare:fcashpay
npm run final:android

iOS

npm run clean-all
npm run apply:fcashpay
npm run prepare:fcashpay
npm run final:ios

Configuration

Enable External Services

To enable external services, set the FCASH_EXTERNAL_SERVICES_CONFIG_LOCATION or FCASH_EXTERNAL_SERVICES_CONFIG_LOCATION environment variable to the location of your configuration before running the apply task.

FCASH_EXTERNAL_SERVICES_CONFIG_LOCATION="~/.fcash/externalServices.json" npm run apply:fcashpay
# or
FCASH_EXTERNAL_SERVICES_CONFIG_LOCATION="~/.fcash/externalServices.json" npm run apply:fcash

About FcashApp

General

FcashApp implements a multisig wallet using p2sh addresses. It supports multiple wallets, each 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, FcashApp 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 Fcash network.

FcashApp 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.

FcashApp Backups and Recovery

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

Information about backup and recovery procedures is available at: https://github.com/fcash-js/fcashpay/blob/master/backupRecovery.md

Previous versions of FcashApp used files as backups. See the following section.

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

Wallet Export Format

FcashApp encrypts the backup with the Stanford JS Crypto Library. To extract the private key of your wallet you can go to settings, choose your wallet, click in "more options", then "wallet information", scroll to the bottom and click in "Extended Private Key". 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 FcashApp. Depending on the key derivationStrategy, addresses are derived using BIP44 or BIP45. Wallets created in FcashApp v1.2 and forward always use BIP44, all previous wallets use BIP45. Also note that since FcashApp version v1.2, non-multisig wallets use address types Pay-to-PublicKeyHash (P2PKH) while multisig wallets still use Pay-to-ScriptHash (P2SH) (key addressType at the backup):

| FcashApp Version | Wallet Type | Derivation Strategy | Address Type | | ------------- | ------------------------- | ------------------- | ------------ | | <1.2 | All | BIP45 | P2SH | | ≥1.2 | Non-multisig | BIP44 | P2PKH | | ≥1.2 | Multisig | BIP44 | P2SH | | ≥1.5 | Multisig Hardware wallets | BIP44 (root m/48’) | P2SH |

Using a tool like Fcash PlayGround all wallet addresses can be generated. (TIP: Use the Address section for P2PKH address type wallets and Multisig Address for P2SH address type wallets). For multisig addresses, the required number of signatures (key m on the export) is also needed to recreate the addresses.

BIP45 note: All addresses generated at FWS with BIP45 use the 'shared cosigner index' (2147483647) so FcashApp address indexes look like: m/45'/2147483647/0/x for main addresses and m/45'/2147483647/1/y for change addresses.

Since version 1.5, FcashApp uses the root m/48' for hardware multisignature wallets. This was coordinated with Ledger and Trezor teams. While the derivation path format is still similar to BIP44, the root was in order to indicate that these wallets are not discoverable by scanning addresses for funds. Address generation for multisignature wallets requires the other fcashpay extended public keys.

Fcash Wallet Service

FcashApp depends on Fcash Wallet Service (FWS) for blockchain information, networking and FcashApp synchronization. A FWS instance can be setup and operational within minutes or you can use a public instance like https://fws.fcash.cash. Switching between FWS instances is very simple and can be done with a click from within FcashApp. FWS also allows FcashApp to interoperate with other wallets like Fcash Wallet CLI.

Translations

FcashApp 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 FcashApp 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

FcashApp 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 FcashApp Signatures

1. Download the [email protected] public key (gpg --recv-keys 1112CFA1)
2. Download FcashApp binary ($FILENAME) and signature file ($FILENAME.sig)
3. Verify the signature by running:

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

# It should return:
Good signature from "FcashApp (visit Fcash.cash) <[email protected]>"

Public Key for FcashApp 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.

Contributing to this project

Anyone and everyone is welcome to contribute. Please take a moment to review the guidelines for contributing.

• Bug reports
• Feature requests
• Pull requests

Current Active Developers GPG keys ID

• 15EDAD8D9F2EB1AF @cmgustavo

• FC283098DA862864 @gabrielbazan7

• DD6D7EAADE12280D @Gamboster

• D87947CC8A32D91C @msalcala11

• 612C9C4DDAC47B61 @rastajpa

• F8FC1D9B1B46486D @matiu

Support

Please see Support requests

License

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