Skycoin

Skycoin is a next-generation cryptocurrency.

Skycoin was written from scratch and designed over four years to realize the ideal of Bitcoin and represents the apex of cryptocurrency design. Skycoin is not designed to add features to Bitcoin, but rather improves Bitcoin by increasing simplicity, security and stripping out everything non-essential.

Some people have hyped the Skycoin Project as leading into "Bitcoin 3.0". The coin itself is not "Bitcoin 3.0", but is rather "Bitcoin 1.0". Bitcoin is a prototype crypto-coin. Skycoin was designed to be what Bitcoin would look like if it were built from scratch, to remedy the rough edges in the Bitcoin design.

no duplicate coin-base outputs
enforced checks for hash collisions
simple deterministic wallets
no transaction malleability
no signature malleability
removal of the scripting language
CoinJoin and normal transactions are indistinguishable
elimination of edge-cases that prevent independent node implementations
<=10 second transaction times
elimination of the need for mining to achieve blockchain consensus

Links

skycoin.net
Skycoin Blog
Skycoin Docs
Skycoin Blockchain Explorer
Skycoin Development Telegram Channel
Skycoin Github Wiki

Changelog

CHANGELOG.md

Installation

Skycoin supports go1.10+.

Go 1.10+ Installation and Setup

Golang 1.10+ Installation/Setup

Go get skycoin

go get github.com/skycoin/skycoin/...

This will download github.com/skycoin/skycoin to $GOPATH/src/github.com/skycoin/skycoin.

You can also clone the repo directly with git clone https://github.com/skycoin/skycoin, but it must be cloned to this path: $GOPATH/src/github.com/skycoin/skycoin.

Run Skycoin from the command line

cd $GOPATH/src/github.com/skycoin/skycoin
make run

Show Skycoin node options

cd $GOPATH/src/github.com/skycoin/skycoin
make run-help

Run Skycoin with options

Example:

cd $GOPATH/src/github.com/skycoin/skycoin
make ARGS="--launch-browser=false -data-dir=/custom/path" run

Docker image

This is the quickest way to start using Skycoin using Docker.

$ docker volume create skycoin-data
$ docker volume create skycoin-wallet
$ docker run -ti --rm \
    -v skycoin-data:/data/.skycoin \
    -v skycoin-wallet:/wallet \
    -p 6000:6000 \
    -p 6420:6420 \
    skycoin/skycoin

This image has a skycoin user for the skycoin daemon to run, with UID and GID 10000. When you mount the volumes, the container will change their owner, so you must be aware that if you are mounting an existing host folder any content you have there will be own by 10000.

The container will run with some default options, but you can change them by just appending flags at the end of the docker run command. The following example will show you the available options.

docker run --rm skycoin/skycoin -help

Access the dashboard: http://localhost:6420.

Access the API: http://localhost:6420/version.

Building your own images

Building your own images.

Development image

The skycoin/skycoindev-cli docker image is provided in order to make easy to start developing Skycoin. It comes with the compiler, linters, debugger and the vim editor among other tools.

API Documentation

REST API

REST API.

JSON-RPC 2.0 API

Deprecated, avoid using this

JSON-RPC 2.0 README.

Skycoin command line interface

CLI command API.

Integrating Skycoin with your application

Skycoin Integration Documentation

Contributing a node to the network

Add your node's ip:port to the peers.txt file. This file will be periodically uploaded to https://downloads.skycoin.net/blockchain/peers.txt and used to seed client with peers.

Note: Do not add Skywire nodes to peers.txt. Only add Skycoin nodes with high uptime and a static IP address (such as a Skycoin node hosted on a VPS).

Creating a new coin

See the newcoin tool README

Running with a custom coin hour burn factor

The coin hour burn factor is the denominator in the ratio of coinhours that must be burned by a transaction. For example, a burn factor of 2 means 1/2 of hours must be burned. A burn factor of 10 means 1/10 of coin hours must be burned.

The coin hour burn factor can be configured with a COINHOUR_BURN_FACTOR envvar. It cannot be configured through the command line.

COINHOUR_BURN_FACTOR=999 ./run.sh

URI Specification

Skycoin URIs obey the same rules as specified in Bitcoin's BIP21. They use the same fields, except with the addition of an optional hours parameter, specifying the coin hours.

Example Skycoin URIs:

skycoin:2hYbwYudg34AjkJJCRVRcMeqSWHUixjkfwY
skycoin:2hYbwYudg34AjkJJCRVRcMeqSWHUixjkfwY?amount=123.456&hours=70
skycoin:2hYbwYudg34AjkJJCRVRcMeqSWHUixjkfwY?amount=123.456&hours=70&label=friend&message=Birthday%20Gift

Development

We have two branches: master and develop.

develop is the default branch and will have the latest code.

master will always be equal to the current stable release on the website, and should correspond with the latest release tag.

Modules

api - REST API interface
api/webrpc - JSON-RPC 2.0 API [deprecated]
cipher - cryptographic library
cli - CLI library
coin - blockchain data structures
daemon - top-level application manager, combining all components (networking, database, wallets)
daemon/gnet - networking library
daemon/pex - peer management
visor - top-level blockchain database layer
visor/blockdb - low-level blockchain database layer
visor/historydb - low-level blockchain database layer for historical blockchain metadata
wallet - wallet file management

Client libraries

Skycoin implements client libraries which export core functionality for usage from other programming languages.

lib/cgo/ - libskycoin C client library ( overview, API reference )

For further details run make docs to generate documetation and read the corresponding README and API references.

Running Tests

make test

Running Integration Tests

There are integration tests for the CLI and HTTP API interfaces. They have two run modes, "stable" and "live.

The stable integration tests will use a skycoin daemon whose blockchain is synced to a specific point and has networking disabled so that the internal state does not change.

The live integration tests should be run against a synced or syncing node with networking enabled.

Stable Integration Tests

make integration-test-stable

or

./ci-scripts/integration-test-stable.sh -v -w

The -w option, run wallet integrations tests.

The -v option, show verbose logs.

Live Integration Tests

The live integration tests run against a live runnning skycoin node, so before running the test, we need to start a skycoin node:

./run-daemon.sh

After the skycoin node is up, run the following command to start the live tests:

./ci-scripts/integration-test.live.sh -v

The above command will run all tests except the wallet related tests. To run wallet tests, we need to manually specify a wallet file, and it must have at least 2 coins and 256 coinhours, it also must have been loaded by the node.

We can specify the wallet by setting two environment variables: WALLET_DIR and WALLET_NAME. The WALLET_DIR represents the absolute path of the wallet directory, and WALLET_NAME represents the wallet file name.

Note: WALLET_DIR is only used by the CLI integration tests. The GUI integration tests use the node's configured wallet directory, which can be controlled with -wallet-dir when running the node.

If the wallet is encrypted, also set WALLET_PASSWORD.

export WALLET_DIR="$HOME/.skycoin/wallets"
export WALLET_NAME="$valid_wallet_filename"
export WALLET_PASSWORD="$wallet_password"

Then run the tests with the following command:

make integration-test-live

or

./ci-scripts/integration-test-live.sh -v -w

Debugging Integration Tests

Run specific test case:

It's annoying and a waste of time to run all tests to see if the test we real care is working correctly. There's an option: -r, which can be used to run specific test case. For exampe: if we only want to test TestStableAddressBalance and see the result, we can run:

./ci-scripts/integration-test-stable.sh -v -r TestStableAddressBalance

Update golden files in integration testdata

Golden files are expected data responses from the CLI or HTTP API saved to disk. When the tests are run, their output is compared to the golden files.

To update golden files, use the -u option:

./ci-scripts/integration-test-live.sh -v -u
./ci-scripts/integration-test-stable.sh -v -u

We can also update a specific test case's golden file with the -r option.

Test coverage

Coverage is automatically generated for make test and integration tests run against a stable node. This includes integration test coverage. The coverage output files are placed in coverage/.

To merge coverage from all tests into a single HTML file for viewing:

make check
make merge-coverage

Then open coverage/all-coverage.html in the browser.

Test coverage for the live node

Some tests can only be run with a live node, for example wallet spending tests. To generate coverage for this, build and run the skycoin node in test mode before running the live integration tests.

In one shell:

make run-integration-test-live-cover

In another shell:

make integration-test-live

After the tests have run, CTRL-C to exit the process from the first shell. A coverage file will be generated at coverage/skycoin-live.coverage.out.

Merge the coverage with make merge-coverage then open the coverage/all-coverage.html file to view it, or generate the HTML coverage in isolation with go tool cover -html

Formatting

All .go source files should be formatted goimports. You can do this with:

make format

Code Linting

Install prerequisites:

make install-linters

Run linters:

make lint

Profiling

A full CPU profile of the program from start to finish can be obtained by running the node with the -profile-cpu flag. Once the node terminates, a profile file is written to -profile-cpu-file (defaults to cpu.prof). This profile can be analyzed with

go tool pprof cpu.prof

The HTTP interface for obtaining more profiling data or obtaining data while running can be enabled with -http-prof. The HTTP profiling interface can be controlling with -http-prof-host and listens on localhost:6060 by default.

See https://golang.org/pkg/net/http/pprof/ for guidance on using the HTTP profiler.

Some useful examples include:

go tool pprof http://localhost:6060/debug/pprof/profile?seconds=10
go tool pprof http://localhost:6060/debug/pprof/heap

A web page interface is provided by http/pprof at http://localhost:6060/debug/pprof/.

Dependencies

Rules

Dependencies must not require cgo. This means dependencies cannot be wrappers around C libraries. Requiring cgo breaks cross compilation and interferes with repeatable (deterministic) builds.

Critical cryptographic dependencies used by code in package cipher are archived inside the cipher folder, rather than in the vendor folder. This prevents a user of the cipher package from accidentally using a different version of the cipher dependencies than were developed, which could have catastrophic but hidden problems.

Management

Dependencies are managed with dep.

To install dep for development:

go get -u github.com/golang/dep/cmd/dep

dep vendors all dependencies into the repo.

If you change the dependencies, you should update them as needed with dep ensure.

Use dep help for instructions on vendoring a specific version of a dependency, or updating them.

When updating or initializing, dep will find the latest version of a dependency that will compile.

Examples:

Initialize all dependencies:

dep init

Update all dependencies:

dep ensure -update -v

Add a single dependency (latest version):

dep ensure github.com/foo/bar

Add a single dependency (more specific version), or downgrade an existing dependency:

dep ensure github.com/foo/bar@tag

Configuration Modes

There are 4 configuration modes in which you can run a skycoin node:

Development Desktop Daemon
Server Daemon
Electron Desktop Client
Standalone Desktop Client

Development Desktop Client Mode

This mode is configured via run-client.sh

$ ./run-client.sh

Server Daemon Mode

The default settings for a skycoin node are chosen for Server Daemon, which is typically run from source. This mode is usually preferred to be run with security options, though -disable-csrf is normal for server daemon mode, it is left enabled by default.

$ ./run-daemon.sh

To disable CSRF:

$ ./run-daemon.sh -disable-csrf

Electron Desktop Client Mode

This mode configures itself via electron-main.js

Standalone Desktop Client Mode

This mode is configured by compiling with STANDALONE_CLIENT build tag. The configuration is handled in cmd/skycoin/skycoin.go

Wallet GUI Development

The compiled wallet source should be checked in to the repo, so that others do not need to install node to run the software.

Instructions for doing this:

Wallet GUI Development README

Releases

Update the version

If the master branch has commits that are not in develop (e.g. due to a hotfix applied to master), merge master into develop
Compile the src/gui/static/dist/ to make sure that it is up to date (see Wallet GUI Development README)
Update all version strings in the repo (grep for them) to the new version
If changes require a new database verification on the next upgrade, update src/skycoin/skycoin.go's dbVerifyCheckpointVersion value
Update CHANGELOG.md: move the "unreleased" changes to the version and add the date
Update files in docker/images/mainnet/repo-info/remote/, adding a new file for the new version and adjusting any configuration text that may have changed
Merge these changes to develop
Follow the steps in pre-release testing
Make a PR merging develop into master
Review the PR and merge it
Tag the master branch with the version number. Version tags start with v, e.g. v0.20.0. Sign the tag. If you have your GPG key in github, creating a release on the Github website will automatically tag the release. It can be tagged from the command line with git tag -as v0.20.0 $COMMIT_ID, but Github will not recognize it as a "release".
Make sure that the client runs properly from the master branch
Release builds are created and uploaded by travis. To do it manually, checkout the master branch and follow the create release builds instructions.

If there are problems discovered after merging to master, start over, and increment the 3rd version number. For example, v0.20.0 becomes v0.20.1, for minor fixes.

Pre-release testing

Performs these actions before releasing:

make check
make integration-test-live (see live integration tests) both with an unencrypted and encrypted wallet, and once with -networking-disabled
go run cmd/cli/cli.go checkdb against a synced node
On all OSes, make sure that the client runs properly from the command line (./run-client.sh and ./run-daemon.sh)
Build the releases and make sure that the Electron client runs properly on Windows, Linux and macOS.
- Use a clean data directory with no wallets or database to sync from scratch and verify the wallet setup wizard.
- Load a test wallet with nonzero balance from seed to confirm wallet loading works
- Send coins to another wallet to confirm spending works
- Restart the client, confirm that it reloads properly

Creating release builds

Create Release builds.

Release signing

Releases are signed with this PGP key:

0x5801631BD27C7874

The fingerprint for this key is:

pub   ed25519 2017-09-01 [SC] [expires: 2023-03-18]
      10A7 22B7 6F2F FE7B D238  0222 5801 631B D27C 7874
uid                      GZ-C SKYCOIN <token@protonmail.com>
sub   cv25519 2017-09-01 [E] [expires: 2023-03-18]

Keybase.io account: https://keybase.io/gzc

Follow the Tor Project's instructions for verifying signatures.

If you can't or don't want to import the keys from a keyserver, the signing key is available in the repo: gz-c.asc.

Releases and their signatures can be found on the releases page.

Instructions for generating a PGP key, publishing it, signing the tags and binaries: https://gist.github.com/gz-c/de3f9c43343b2f1a27c640fe529b067c

Responsible Disclosure

Security flaws in skycoin source or infrastructure can be sent to security@skycoin.net. Bounties are available for accepted critical bug reports.

PGP Key for signing:

Key ID: 0x5801631BD27C7874