dcrwallet

dcrwallet

dcrwallet is a daemon handling Decred wallet functionality. All interaction with the wallet is performed over RPC.

Public and private keys are derived using the hierarchical deterministic format described by BIP0032. Unencrypted private keys are not supported and are never written to disk. dcrwallet uses the m/44'/<coin type>'/<account>'/<branch>/<address index> HD path for all derived addresses, as described by BIP0044.

Due to the sensitive nature of public data in a BIP0032 wallet, dcrwallet provides the option of encrypting not just private keys, but public data as well. This is intended to thwart privacy risks where a wallet file is compromised without exposing all current and future addresses (public keys) managed by the wallet. While access to this information would not allow an attacker to spend or steal coins, it does mean they could track all transactions involving your addresses and therefore know your exact balance. In a future release, public data encryption will extend to transactions as well.

dcrwallet provides two modes of operation to connect to the Decred network. The first (and default) is to communicate with a single trusted dcrd instance using JSON-RPC. The second is a privacy-preserving Simplified Payment Verification (SPV) mode (enabled with the --spv flag) where the wallet connects either to specified peers (with --spvconnect) or peers discovered from seeders and other peers. Both modes can be switched between with just a restart of the wallet. It is advised to avoid SPV mode for heavily-used wallets which require downloading most blocks regardless.

Not all functionality is available when running in SPV mode. Some of these features may become available in future versions, but only if a consensus vote passes to activate the required changes. Currently, the following features are disabled or unavailable to SPV wallets:

• Voting

• Revoking tickets before expiry

• Determining exact number of live and missed tickets (as opposed to simply unspent).

Wallet clients interact with the wallet using one of two RPC servers:

1. A legacy JSON-RPC server inspired by the Bitcoin Core rpc server

   The JSON-RPC server exists to ease the migration of wallet applications from Core, but complete compatibility is not guaranteed. Some portions of the API (and especially accounts) have to work differently due to other design decisions (mostly due to BIP0044). However, if you find a compatibility issue and feel that it could be reasonably supported, please report an issue. This server is enabled by default as long as a username and password are provided.

2. A gRPC server

   The gRPC server uses a new API built for dcrwallet, but the API is not stabilized. This server is enabled by default and may be disabled with the config option --nogrpc. If you don't mind applications breaking due to API changes, don't want to deal with issues of the legacy API, or need notifications for changes to the wallet, this is the RPC server to use. The gRPC server is documented here.

Installation and updating

Binaries (Windows/Linux/macOS)

Binary releases are provided for common operating systems and architectures:

https://github.com/decred/decred-binaries/releases

Build from source (all platforms)

Building or updating from source requires the following build dependencies:

• Go 1.10 or 1.11

  Installation instructions can be found here: https://golang.org/doc/install. It is recommended to add $GOPATH/bin to your PATH at this point.

• Vgo (Go 1.10 only)

  The GO111MODULE experiment is used to manage project dependencies and provide reproducible builds. The module experiment is provided by the Go 1.11 toolchain, but the Go 1.10 toolchain does not provide any module support. To perform module-aware builds with Go 1.10, vgo (a drop-in replacement for the go command) must be used instead.

To build and install from a checked-out repo, run go install in the repo's root directory. Some notes:

• Set the GO111MODULE=on environment variable if using Go 1.11 and building from within GOPATH.

• Replace go with vgo when using Go 1.10.

• The dcrwallet executable will be installed to $GOPATH/bin. GOPATH defaults to $HOME/go (or %USERPROFILE%\go on Windows) if unset.

Docker

All tests and linters may be run in a docker container using the script run_tests.sh. This script defaults to using the current supported version of go. You can run it with the major version of go you would like to use as the only arguement to test a previous on a previous version of go (generally decred supports the current version of go and the previous one).

./run_tests.sh 1.10

To run the tests locally without docker:

./run_tests.sh local

Getting Started

The following instructions detail how to get started with dcrwallet connecting to a localhost dcrd. Commands should be run in cmd.exe or PowerShell on Windows, or any terminal emulator on *nix.

• Run the following command to start dcrd:

dcrd -u rpcuser -P rpcpass

• Run the following command to create a wallet:

dcrwallet -u rpcuser -P rpcpass --create

• Run the following command to start dcrwallet:

dcrwallet -u rpcuser -P rpcpass

If everything appears to be working, it is recommended at this point to copy the sample dcrd and dcrwallet configurations and update with your RPC username and password.

PowerShell (Installed from source):

PS> cp $env:GOPATH\src\github.com\decred\dcrd\sample-dcrd.conf $env:LOCALAPPDATA\Dcrd\dcrd.conf
PS> cp $env:GOPATH\src\github.com\decred\dcrwallet\sample-dcrwallet.conf $env:LOCALAPPDATA\Dcrwallet\dcrwallet.conf
PS> $editor $env:LOCALAPPDATA\Dcrd\dcrd.conf
PS> $editor $env:LOCALAPPDATA\Dcrwallet\dcrwallet.conf

Linux/BSD/POSIX (Installed from source):

$ cp $GOPATH/src/github.com/decred/dcrd/sample-dcrd.conf ~/.dcrd/dcrd.conf
$ cp $GOPATH/src/github.com/decred/dcrwallet/sample-dcrwallet.conf ~/.dcrwallet/dcrwallet.conf
$ $EDITOR ~/.dcrd/dcrd.conf
$ $EDITOR ~/.dcrwallet/dcrwallet.conf

Issue Tracker

The integrated github issue tracker is used for this project.

License

dcrwallet is licensed under the liberal ISC License.