Bitcoin-S-Sidechains

This is a base implementation for a sidechain in Scala. There are currently two branches under development on this repository

Mainchain - this is a slightly modified version of bitcoin to support the validation of SPV proofs. This is a soft fork change as described in section 3.2 in the sidechains whitepaper
Alpha - this is the actual sidechain implementation where all new op codes, experimental features etc. happen

What are sidechains?

Sidechains are a blockchain that is pegged to another blockchain. An example of this could be a sidechain designed to facilitate sports betting that is pegged to the bitcoin blockchain. For more information on the design of sidechains please see the whitepaper.

Goal

This implementation of a sidechain is designed to be a base implementation for which other sidechains (and their features) can be built off of. For the most part, it is going to mirror the elements project. This project aims to provide a solid base implementation on the JVM.

TODO:

Implement verification of SPV proofs inside of the mainchain branch
Implement REORGPROOFVERIFY & WITHDRAWPROOFVERIFY
Implement disabled op codes in Bitcoin (OP_OR, OP_AND, OP_XOR...)
Signed blocks
Deterministic Pegs

Examples from Bitcoin-S-Core

Bitcoin-S-Sidechains is a fork of Bitcoin-S-Core. Here are examples of how Bitcoin-S-Core works and how to run the test cases.

chris@chris:~/dev/bitcoins-core-chris$ sbt console

scala> import org.bitcoins.protocol.transaction._
import org.bitcoins.protocol.transaction._

scala> import org.bitcoins.protocol.script._
import org.bitcoins.protocol.script._

scala> val simpleRawTransaction = "0100000001ccf318f0cbac588a680bbad075aebdda1f211c94ba28125b0f627f9248310db3000000006b4830450221008337ce3ce0c6ac0ab72509f889c1d52701817a2362d6357457b63e3bdedc0c0602202908963b9cf1a095ab3b34b95ce2bc0d67fb0f19be1cc5f7b3de0b3a325629bf01210241d746ca08da0a668735c3e01c1fa02045f2f399c5937079b6434b5a31dfe353ffffffff0210335d05000000001976a914b1d7591b69e9def0feb13254bace942923c7922d88ac48030000000000001976a9145e690c865c2f6f7a9710a474154ab1423abb5b9288ac00000000"
simpleRawTransaction: String = 0100000001ccf318f0cbac588a680bbad075aebdda1f211c94ba28125b0f627f9248310db3000000006b4830450221008337ce3ce0c6ac0ab72509f889c1d52701817a2362d6357457b63e3bdedc0c0602202908963b9cf1a095ab3b34b95ce2bc0d67fb0f19be1cc5f7b3de0b3a325629bf01210241d746ca08da0a668735c3e01c1fa02045f2f399c5937079b6434b5a31dfe353ffffffff0210335d05000000001976a914b1d7591b69e9def0feb13254bace942923c7922d88ac48030000000000001976a9145e690c865c2f6f7a9710a474154ab1423abb5b9288ac00000000

scala> val tx = Transaction(simpleRawTransaction)
tx: org.bitcoins.protocol.transaction.Transaction = TransactionImpl(1,List(TransactionInputImpl(TransactionOutPointImpl(b30d3148927f620f5b1228ba941c211fdabdae75d0ba0b688a58accbf018f3cc,0),P2PKHScriptSignatureImpl(4830450221008337ce3ce0c6ac0ab72509f889c1d52701817a2362d6357457b63e3bdedc0c0602202908963b9cf1a095ab3b34b95ce2bc0d67fb0f19be1cc5f7b3de0b3a325629bf01210241d746ca08da0a668735c3e01c1fa02045f2f399c5937079b6434b5a31dfe353,List(BytesToPushOntoStackImpl(72), ScriptConstantImpl(30450221008337ce3ce0c6ac0ab72509f889c1d52701817a2362d6357457b63e3bdedc0c0602202908963b9cf1a095ab3b34b95ce2bc0d67fb0f19be1cc5f7b3de0b3a325629bf01), BytesToPushOntoStackImpl(33), ScriptConstantImpl(0241d746ca08da0a668735c3e01c1fa02045f2f399c5937079b6434b5a31dfe353))),4294967295)),List(TransactionOutputImpl(89994000 ...

This gives us an example of a bitcoin transaction that is encoded in hex format that is deserialized to a native Scala object called a Transaction.

Transactions are run through the interpreter to check the validity of the Transaction. These are packaged up into an object called ScriptProgram, which contains the following:

The transaction that is being checked
The specific input index that it is checking
The scriptPubKey for the crediting transaction
The flags used to verify the script

Here is an example of a transaction spending a scriptPubKey which is correctly evaluated with our interpreter implementation:

chris@chris:~/dev/bitcoins-core$ sbt console
[info] Loading project definition from /home/chris/dev/bitcoins-core/project
[info] Set current project to bitcoins (in build file:/home/chris/dev/bitcoins-core/)
[info] Starting scala interpreter...
[info] 
Welcome to Scala version 2.11.7 (Java HotSpot(TM) 64-Bit Server VM, Java 1.8.0_92).
Type in expressions to have them evaluated.
Type :help for more information.

scala> import org.bitcoins.protocol.script._
import org.bitcoins.protocol.script._

scala> import org.bitcoins.protocol.transaction._
import org.bitcoins.protocol.transaction._

scala> import org.bitcoins.script._
import org.bitcoins.script._

scala> import org.bitcoins.script.interpreter._
import org.bitcoins.script.interpreter._

scala> import org.bitcoins.policy._
import org.bitcoins.policy._

scala> val spendingTx = Transaction("0100000001ccf318f0cbac588a680bbad075aebdda1f211c94ba28125b0f627f9248310db3000000006b4830450221008337ce3ce0c6ac0ab72509f889c1d52701817a2362d6357457b63e3bdedc0c0602202908963b9cf1a095ab3b34b95ce2bc0d67fb0f19be1cc5f7b3de0b3a325629bf01210241d746ca08da0a668735c3e01c1fa02045f2f399c5937079b6434b5a31dfe353ffffffff0210335d05000000001976a914b1d7591b69e9def0feb13254bace942923c7922d88ac48030000000000001976a9145e690c865c2f6f7a9710a474154ab1423abb5b9288ac00000000")
spendingTx: org.bitcoins.protocol.transaction.Transaction = TransactionImpl(1,List(TransactionInputImpl(TransactionOutPointImpl(b30d3148927f620f5b1228ba941c211fdabdae75d0ba0b688a58accbf018f3cc,0),P2PKHScriptSignatureImpl(4830450221008337ce3ce0c6ac0ab72509f889c1d52701817a2362d6357457b63e3bdedc0c0602202908963b9cf1a095ab3b34b95ce2bc0d67fb0f19be1cc5f7b3de0b3a325629bf01210241d746ca08da0a668735c3e01c1fa02045f2f399c5937079b6434b5a31dfe353,List(BytesToPushOntoStackImpl(72), ScriptConstantImpl(30450221008337ce3ce0c6ac0ab72509f889c1d52701817a2362d6357457b63e3bdedc0c0602202908963b9cf1a095ab3b34b95ce2bc0d67fb0f19be1cc5f7b3de0b3a325629bf01), BytesToPushOntoStackImpl(33), ScriptConstantImpl(0241d746ca08da0a668735c3e01c1fa02045f2f399c5937079b6434b5a31dfe353))),4294967295)),List(TransactionOutputImpl(8...
scala> val scriptPubKey = ScriptPubKey("76a91431a420903c05a0a7de2de40c9f02ebedbacdc17288ac")
scriptPubKey: org.bitcoins.protocol.script.ScriptPubKey = P2PKHScriptPubKeyImpl(76a91431a420903c05a0a7de2de40c9f02ebedbacdc17288ac,List(OP_DUP, OP_HASH160, BytesToPushOntoStackImpl(20), ScriptConstantImpl(31a420903c05a0a7de2de40c9f02ebedbacdc172), OP_EQUALVERIFY, OP_CHECKSIG))

scala> val inputIndex = 0
inputIndex: Int = 0

scala> val program = ScriptProgram(spendingTx,scriptPubKey,inputIndex, Policy.standardScriptVerifyFlags)
program: org.bitcoins.script.PreExecutionScriptProgram = PreExecutionScriptProgramImpl(TransactionSignatureComponentImpl(TransactionImpl(1,List(TransactionInputImpl(TransactionOutPointImpl(b30d3148927f620f5b1228ba941c211fdabdae75d0ba0b688a58accbf018f3cc,0),P2PKHScriptSignatureImpl(4830450221008337ce3ce0c6ac0ab72509f889c1d52701817a2362d6357457b63e3bdedc0c0602202908963b9cf1a095ab3b34b95ce2bc0d67fb0f19be1cc5f7b3de0b3a325629bf01210241d746ca08da0a668735c3e01c1fa02045f2f399c5937079b6434b5a31dfe353,List(BytesToPushOntoStackImpl(72), ScriptConstantImpl(30450221008337ce3ce0c6ac0ab72509f889c1d52701817a2362d6357457b63e3bdedc0c0602202908963b9cf1a095ab3b34b95ce2bc0d67fb0f19be1cc5f7b3de0b3a325629bf01), BytesToPushOntoStackImpl(33), ScriptConstantImpl(0241d746ca08da0a668735c3e01c1fa02045f2f399c5937079...
scala> ScriptInterpreter.run(program)
res0: org.bitcoins.script.result.ScriptResult = ScriptOk

Running tests

To run the entire test suite all you need to do is run the following command

chris@chris:~/dev/bitcoins-core$ sbt test
[info] Run completed in 8 seconds, 805 milliseconds.
[info] Total number of tests run: 613
[info] Suites: completed 91, aborted 0
[info] Tests: succeeded 613, failed 0, canceled 0, ignored 0, pending 0
[info] All tests passed.
[success] Total time: 17 s, completed May 7, 2016 1:11:34 PM
chris@chris:~/dev/bitcoins-core$

To run a specific suite of tests you can specify the suite name in the following way

chris@chris:~/dev/bitcoins-core$ sbt
> test-only *ScriptInterpreterTest*
[info] ScriptInterpreterTest:
[info] ScriptInterpreter
[info] - must evaluate all the scripts from the bitcoin core script_tests.json
[info] Run completed in 8 seconds, 208 milliseconds.
[info] Total number of tests run: 1
[info] Suites: completed 1, aborted 0
[info] Tests: succeeded 1, failed 0, canceled 0, ignored 0, pending 0
[info] All tests passed.
>

gtostock / bitcoin-s-sidechains