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

Changelog

CHANGELOG.md

Installation

Skycoin supports go1.14+.

Go 1.14+ Installation and Setup

Golang 1.14+ Installation/Setup

Go get skycoin

$ go get github.com/SkycoinProject/skycoin/cmd/...

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

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

Run Skycoin from the command line

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

Show Skycoin node options

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

Run Skycoin with options

Example:

$ cd $GOPATH/src/github.com/SkycoinProject/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 \
    SkycoinProject/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 SkycoinProject/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 SkycoinProject/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.

The SkycoinProject/skycoindev-dind docker image comes with docker installed and all tools available on SkycoinProject/skycoindev-cli:develop docker image.

Also, the SkycoinProject/skycoindev-vscode docker image is provided to facilitate the setup of the development process with Visual Studio Code and useful tools included in SkycoinProject/skycoindev-cli.

API Documentation

REST API

REST API.

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.com/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

Daemon CLI Options

See the Skycoin Daemon CLI options

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

Additonally, if no skycoin: prefix is present when parsing, the string may be treated as an address:

2hYbwYudg34AjkJJCRVRcMeqSWHUixjkfwY

However, do not use this URI in QR codes displayed to the user, because the address can't be disambiguated from other Skyfiber coins.

Wire protocol user agent

Wire protocol user agent description

Offline transaction signing

Before doing the offline transaction signing, we need to have the unsigned transaction created. Using the skycoin-cli tool to create an unsigned transaction in hot wallet, and copy the hex encoded transaction to the computer where the cold wallet is installed. Then use the skycoin-cli tool to sign it offline.

Create an unsigned transaction

The skycoin-cli tool replys on the APIs of the skycoin node, hence we have to start the node before running the tool.

Go to the project root and run:

$ ./run-client.sh -launch-browser=false

Once the node is started, we could use the following command to create an unsigned transaction.

$ skycoin-cli createRawTransactionV2 $WALLET_FILE $RECIPIENT_ADDRESS $AMOUNT --unsign

Note: Don't forget the --unsign flag, otherwise it would try to sign the transaction.

View Output

b700000000e6b869f570e2bfebff1b4d7e7c9e86885dbc34d6de988da6ff998e7acd7e6e14010000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000010000007531184ad0afeebbff2049b855e0921329cb1cb74d769ac57c057c9c8bd2b6810100000000ed5ea2ca4fe9b4560409b50c5bf7cb39b6c5ff6e50690f00000000000000000000000000

Copy and save the generated transaction string. We will sign it with a cold wallet offline in the next section.

Sign the transaction

The skycoin node needs to have the most recently DB so that the user would not lose much coin hours when signing the transaction. We could copy the full synchronized data.db from the hot wallet to the computer where the cold wallet is installed. And place it in $HOME/.skycoin/data.db. Then start the node with the network disabled.

$ ./run-client.sh -launch-browser=false -disable-networking

Run the following command to sign the transaction:

$ skycoin-cli signTransaction $RAW_TRANSACTION

The $RAW_TRANSACTION is the transaction string that we generated in the hot wallet.

If the cold wallet is encrypted, you will be prompted to enter the password to sign the transaction.

View Output

b700000000e6b869f570e2bfebff1b4d7e7c9e86885dbc34d6de988da6ff998e7acd7e6e14010000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000010000007531184ad0afeebbff2049b855e0921329cb1cb74d769ac57c057c9c8bd2b6810100000000ed5ea2ca4fe9b4560409b50c5bf7cb39b6c5ff6e50690f00000000000000000000000000

Once the transaction is signed, we could copy and save the signed transaction string and broadcast it in the hot wallet.

$ skycoin-cli broadcastTransaction $SIGNED_RAW_TRANSACTION

A transaction id would be returned and you can check it in the explorer.

Deploy a public Skycoin API node with HTTPS

We recommend using caddy server to deploy a public Skycoin API node on a Linux server. The public API node should have the HTTPS support, which could be handled automatically by the caddy server. But we need to have a domain and create a DNS record to bind the server ip address to it.

Suppose we're going to deploy a Skycoin API node on apitest.skycoin.com, and we have already bound the server's IP to it. Follow the steps below to complete the deployment.

Install and run a skycoin api node

# Create a skycoin folder so that the files could be isolated
$ mkdir $HOME/skycoin && cd $HOME/skycoin
# Download the skycoin binary file
$ wget https://downloads.skycoin.com/wallet/skycoin-0.26.0-gui-standalone-linux-x64.tar.gz
$ tar -zxvf skycoin-0.26.0-gui-standalone-linux-x64.tar.gz
$ cd skycoin-0.26.0-gui-standalone-linux-x64
$ ./skycoin -web-interface-port=6420 -host-whitelist=$DOMAIN_NAME -enable-api-sets="READ,TXN"

Note: we should running the skycoin node with -host-whitelist flag, otherwise it would throw 403 Forbidden error.

Install the caddy server

# Create a caddy folder
$ mkdir $HOME/caddy && cd $HOME/caddy
# Download the caddy server binary file
$ wget https://github.com/caddyserver/caddy/releases/download/v1.0.4/caddy_v1.0.4_linux_amd64.tar.gz
$ tar -zxvf caddy_v1.0.4_linux_amd64.tar.gz
$ cd caddy_v1.0.4_linux_amd64

The caddy tool would be exist in the folder, let's create a Caddyfile to define the reverse proxy rules now.

cat <<EOF >Caddyfile
apitest.skycoin.com {
   proxy / localhost:6420 {
      transparent
   }
}
EOF

Then run the caddy server

$ ./caddy

You will be prompted to enter an email address to receive the notifications from let's Encrypt. That's all about the deployment, check the https://apitest.skycoin.com/api/v1/version to see if the Skycoin API node is working correctly.

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
cipher - cryptographic library (key generation, addresses, hashes)
cipher/base58 - Base58 encoding
cipher/encoder - reflect-based deterministic runtime binary encoder
cipher/encrypt - at-rest data encryption (chacha20poly1305+scrypt)
cipher/go-bip39 - BIP-39 seed generation
cli - CLI library
coin - blockchain data structures (blocks, transactions, unspent outputs)
daemon - top-level application manager, combining all components (networking, database, wallets)
daemon/gnet - networking library
daemon/pex - peer management
params - configurable transaction verification parameters
readable - JSON-encodable representations of internal structures
skycoin - core application initialization and configuration
testutil - testing utility methods
transaction - methods for creating transactions
util - miscellaneous utilities
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.

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

$ ./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:

$ make integration-test-live

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:

API_WALLET_ID, which is the filename (without path), that is loaded by the daemon to test against. This is the "id" field in API requests. It is used by the API integration tests. The wallet directory that the daemon uses can be controlled with the -wallet-dir option.
CLI_WALLET_FILE, which is the filename (with path), to be used by the CLI integration tests

If the wallet is encrypted, also set WALLET_PASSWORD.

Example of running the daemon with settings for integration tests:

$ export API_WALLET_ID="$valid_wallet_filename"
$ export CLI_WALLET_FILE="$HOME/.skycoin/wallets/$valid_wallet_filename"
$ export WALLET_PASSWORD="$wallet_password"
$ make run-integration-test-live

Then run the tests with the following command:

$ make integration-test-live-wallet

There are two other live integration test modes for CSRF disabled and networking disabled.

To run the CSRF disabled tests:

$ export API_WALLET_ID="$valid_wallet_filename"
$ export CLI_WALLET_FILE="$HOME/.skycoin/wallets/$valid_wallet_filename"
$ export WALLET_PASSWORD="$wallet_password"
$ make run-integration-test-live-disable-csrf

$ make integration-test-live-disable-csrf

To run the networking disabled tests, which require a live wallet:

$ export API_WALLET_ID="$valid_wallet_filename"
$ export CLI_WALLET_FILE="$HOME/.skycoin/wallets/$valid_wallet_filename"
$ export WALLET_PASSWORD="$wallet_password"
$ make run-integration-test-live-disable-networking

Then run the tests with the following command:

$ make integration-test-live-wallet

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 example: 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 provided make command:

$ make update-golden-files

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

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

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 controlled 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/.

Fuzzing

Fuzz tests are run with go-fuzz. Follow the instructions on the go-fuzz page to install it.

Fuzz tests are written for the following packages:

base58

To fuzz the cipher/base58 package,

$ make fuzz-base58

encoder

To fuzz the cipher/encoder package,

$ make fuzz-encoder

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 go modules.

We still use the vendor folder to store our dependencies in case any of the them are removed from the internet in the future.

When the main module contains a top-level vendor directory and its go.mod file specifies go 1.14 or higher, the go command now defaults to -mod=vendor for operations that accept that flag.

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

Translations

You can find information about how to work with translation files in the Translations 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
Make sure the translations are up to date. See the i18n README for instructions on how to update translations and how to check if they are up to date.
Compile the src/gui/static/dist/ to make sure that it is up to date (see Wallet GUI Development README)
Update version strings to the new version in the following files: electron/package-lock.json, electron/package.json, electron/skycoin/current-skycoin.json, src/cli/cli.go, src/gui/static/src/current-skycoin.json, src/cli/integration/testdata/status*.golden, template/coin.template, README.md files .
If changes require a new database verification on the next upgrade, update src/SkycoinProject/skycoin.go's DBVerifyCheckpointVersion value
Update CHANGELOG.md: move the "unreleased" changes to the version and add the date
Update the files in https://github.com/skycoin/repo-info by following the metadata update procedure,
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.

Check the translations

Run make check-lang to check if the translation files of the UI are updated. If there is any error running that command, one or more translation files may need to be updated. For more information, check the translations section.

Pre-release testing

Performs these actions before releasing:

make check
make integration-test-live
make integration-test-live-disable-networking (requires node run with -disable-networking)
make integration-test-live-disable-csrf (requires node run with -disable-csrf)
make intergration-test-live-wallet (see live integration tests) 6 times: with an unencrypted and encrypted wallet for each wallet type: deterministic, bip44 and collection
go run cmd/skycoin-cli/skycoin-cli.go checkdb against a fully synced database
go run cmd/skycoin-cli/skycoin-cli.go checkDBDecoding against a fully synced database
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
For both the Android and iOS mobile wallets, configure the node url to be https://staging.node.skycoin.com and test all operations to ensure it will work with the new node version.

Creating release builds

Create Release builds.

Release signing

Releases are signed with this PGP key:

0x913BBD5206B19620

The fingerprint for this key is:

pub   ed25519 2019-09-17 [SC] [expires: 2023-09-16]
      98F934F04F9334B81DFA3398913BBD5206B19620
uid           [ultimate] iketheadore skycoin <luxairlake@protonmail.com>
sub   cv25519 2019-09-17 [E] [expires: 2023-09-16]

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

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: iketheadore.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/iketheadore/6485585ce2d22231c2cb3cbc77e1d7b7

Responsible Disclosure

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

PGP Key for signing:

Key ID: 0x913BBD5206B19620