Scorex, the Modular Blockchain Framework

Bitcoin Summer School
Scorex, the Modular Blockchain Framework
Alexander Chepurnoy
(aka kushti)
@chepurnoy
IOHK Research

Section 1. „Scorex In General“

Use Cases
● Implement new consensus protocol and plug it easily into
a prototypical blockchain system to run a system against a
testbed
● In the same way, implement and spread a proof-of-concept
impl. for anew transactional language

Use Cases
● Proof-of-Stake protocols
● Permacoin implementation

The Problem
● Bitcoin(reference impl): > 80K lines of C++ code
● EthereumJ: > 55K of Java code
● Nxt: > 40K lines of Java code
● Every codebase is highly optimized for a concrete
production environment

The Problem
● It is hard to locate, inject, swap functionalities
● Hard to make experiments/prototypes

Scorex in General
● Find fast where to inject
● Modular stacked design
● Externalised cryptography(scrypto)
● One testnet application atm(Lagonaki)

Scorex in General, pt 2
● Everything is open-sourced immediately
● CC0 license
● Maintained by IOHK Research

Competitors
Intel's „Sawtooth Lake“
(https://github.com/IntelLedger)
„a highly modular platform for building, deploying and
running distributed ledgers" (Intel Corp.)

Intel's „Sawtooth Lake“
● Consensus / „transaction family“
● Proof of Elapsed Time (Intel SGX)
● Assets marketplace
● Python
● Apache License 2.0

Section 2. „Scorex In Details“

Scorex is in Scala
● Functional language, strict static typing
● JVM
● Could be enhanced with any JVM language(Java, Clojure,
Kotlin, Groovy, Jython, Frege etc)

Development Philosophy
● Flexible design could be hard to understand
● Simple code could be not flexible or error-prone
● We need to find a balance!
● Give a maximum for free!

Design In General
● Compact core – always for free
● Consensus module - implement or take ready
● Transactional module - implement or take ready
● Network protocols – partly for free
● API – partly for free
● Application – lean!
● Wallet, configs – partly for free

A Module
● Writes and reads certain block parts
● Implements corresponding interface

Code Quality
● Compact code, strict types
● Good test coverage(70-80%)
● Continuous integration

Getting Started
● Docs on GitHub:
https://github.com/ScorexProject/Scorex/wiki/Getting-started
● Java 8 SDK
● sbt is recommended for Scala

Adding Modules
libraryDependencies ++= Seq(
"org.consensusresearch" %% "scorex-basics" % "1.+",
"org.consensusresearch" %% "scorex-consensus" % "1.+",
"org.consensusresearch" %% "scorex-transaction" % "1.+"
)
scorex-basics -core
scorex-consensus - two Proof-of-Stake consensus protocols
scorex-transaction – simplest transactions

Adding Modules
libraryDependencies ++= Seq(
"org.consensusresearch" %% "scorex-basics" % "1.+",
"org.consensusresearch" %% "scorex-perma" % "1.+",
"org.consensusresearch" %% "scorex-transaction" % "1.+"
)
scorex-perma – Permacoin consensus protocol implementation

Application - modules
class MyApplication(val settingsFilename: String) extends Application {
// Your application config
override val applicationName = "my cool application"
override val appVersion = ApplicationVersion(0, 1, 0)
override implicit lazy val settings = new Settings with
TransactionSettings {
override val filename: String = settingsFilename
}
// Define consensus and transaction modules of your application
override implicit lazy val consensusModule = new
NxtLikeConsensusModule()
override implicit lazy val transactionModule = new
SimpleTransactionModule()(settings, this)

Application - API
// Define API routes of your application
override lazy val apiRoutes = Seq(
BlocksApiRoute(this),
TransactionsApiRoute(this),
NxtConsensusApiRoute(this),
WalletApiRoute(this),
PaymentApiRoute(this),
UtilsApiRoute(this),
PeersApiRoute(this),
AddressApiRoute(this)
)
// API types are required for swagger support
override lazy val apiTypes = Seq(
typeOf[BlocksApiRoute],
typeOf[TransactionsApiRoute],
typeOf[NxtConsensusApiRoute],
typeOf[WalletApiRoute],
typeOf[PaymentApiRoute],
typeOf[UtilsApiRoute],
typeOf[PeersApiRoute],
typeOf[AddressApiRoute]
)

Application – network protocols
// Create your custom messages and add them to additionalMessageSpecs
override lazy val additionalMessageSpecs =
TransactionalMessagesRepo.specs
// Start additional actors
actorSystem.actorOf(Props(classOf[UnconfirmedPoolSynchronizer], this))
}

Launch The Application
object MyApplication extends App {
// Provide filename by command-line arguments
val filename = args.headOption.getOrElse("settings.json")
// Create application instance
val application = new MyApplication(filename)
// Run it
application.run()
// Generate account in your wallet
if (application.wallet.privateKeyAccounts().isEmpty)
application.wallet.generateNewAccounts(1)
}

Settings
https://github.com/ScorexProject/Scorex/wiki/Settings
{
"p2p": {
"bindAddress": "0.0.0.0",
"upnp": false,
"upnpGatewayTimeout": 7000,
"upnpDiscoverTimeout": 3000,
"port": 9084,
"knownPeers": [
"23.94.190.226:9185"
],
"maxConnections": 10
},
"walletDir": "/tmp/scorex/wallet",
"dataDir": "/tmp/scorex/data",
"rpcPort": 9085,
"rpcAllowed": [],
"maxRollback": 100,
"blockGenerationDelay": 0,
"genesisTimestamp": 1460952000000,
"apiKeyHash": "GmVvcpx1BRUPDZiADbZ7a6zgQV3Sgj2GhNoEiTH9Drdx",
"cors": false
}

Lagonaki
● Permacoin implementation
● Simplest transactional module, account-2-account
payments

Launch Lagonaki
● docker run -i -p 9085:9085 "scorex/lagonaki:1.2.7"
● debian package
● https://github.com/ScorexProject/Lagonaki

Lagonaki Block Explorer
http://cryptorevolution.me/

Run own network
● src/main/resources/lagonaki.conf
app {
product = "Scorex"
release = "Lagonaki"
version = "1.2.7"
consensusAlgo = "perma"
}

1.2.7 → 1.3.0
● Flexible state models(now account-based)
● Flexible signing schemes(now EdDSA-25519 only)

Ergaki
● Blockchain for protocols
● Rollerchain implementation: safely prunable fullblocks
● Σ-coin implementation: wide class of NIZKPoK for DLOG
statements
● Rent-a-Box fee model
● Improved difficulty adjustment

Scrypto
● Еncoding functions(Base16/58/64)
● Hash functions(Blake2, Keccak etc)
● 25519 from WhisperSystems
● Authenticated data structures(Merkle trees, authenticated
skiplists coming in next release)

Contribution
● Comments
● Todos (search for „todo:“)
● Documentation
● Bugs
● Bitcoin UTXO model implementation (BitcoinJ)
● EVM implementation (EthereumJ)

Reach Us
● Maillist https://scorex-dev.groups.io/g/main
● GitHub https://github.com/ScorexProject
● https://iohk.io/team/

Questions?
https://github.com/ScorexProject/Scorex

Scorex, the Modular Blockchain Framework

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