/naivechain

A minimum viable plasma chain.

Primary LanguageJavaScriptApache License 2.0Apache-2.0

Simple plasma implementation

Plasma consists of three major parts.

  1. Plasma chain: A simple proof-of-authority chain where the actual transactions take place.
  2. Plasma contract: A smart contract deployed on root chain which handles the deposits and withdrawals for the child chain (plasma chain).
  3. Ethereum blockchain: The root chain which only records the block headers of the plasma chain.

The complete cycle of interacting with plasma is made up of three stages.

Deposit

Participants deposit to the plasma contract on the root chain. Then the operator at the plasma chain will construct a deposit transaction according to the contract event when building a new block.

Transact

Participants could transact with each other on the plasma chain without notifying the root chain. Only when every block is created by the operator, it will submit the block header to the plasma contract on the root chain.

Withdraw

A withdrawal is initiated by calling the plasma contract. After creating a withdrawal, user needs to wait 7 days for other participants to challenge it. If anyone could prove the given withdrawal that has been spent later on the plasma chain, the withdrawal will be canceled. Otherwise, after 7 days and without any other withdrawals with higher priority, user could withdraw his funds back to the root chain.

Prerequisite

  1. Launch an Ethereum private chain as the root chain.
  2. Deploy the plasma smart contract on the root chain manually.
  3. Set the contract address at config file (config.js).
  4. Create accounts on Ethereum blockchain for the operator and participants.

Run a plasma chain

npm install
HTTP_PORT=3001 npm start

HTTP API

Block related

Get blockchain

Get the whole blockchain.

Parameter

None

Sample
curl http://localhost:3001/blocks

Mine blocks

Miner mines a new block.

Parameter

None

Sample
curl -X POST http://localhost:3001/mineBlock

Transaction related

Create a transaction

Create a transaction to other participants. User could specify at most two UTXOs to spend. Also note that the units used in field amount is ether.

Parameter
Name Type Required Description
blkNum1 Integer Yes First UTXO position
txIndex1 Integer Yes First UTXO position
oIndex1 Integer Yes First UTXO position
blkNum2 Integer No Second UTXO position
txIndex2 Integer No Second UTXO position
oIndex2 Integer No Second UTXO position
newOwner Address Yes Transfer funds to whom
amount Decimal Yes How much ether (in ether)
from Address Yes Transfer funds from whom
Sample
curl -H "Content-type:application/json" --data '{"from": "0xC973531975B1EE371164DCcB9529b89A7bCD1c4A", "blkNum1": 4, "txIndex1": 1, "oIndex": 0, "newOwner": "0x52A6d6c37648Fb1bCd3c641DF3DB35F12a87C4fc", "amount": 0.05}' http://localhost:3001/transact

Deposit related

Deposit

Deposit funds to Plasma smart contract.

Parameter
Name Type Required Description
address Address Yes Deposit from whom
amount Integer Yes How much funds to deposit
Sample
curl -H "Content-type:application/json" --data '{"address": "0xC973531975B1EE371164DCcB9529b89A7bCD1c4A", "amount": 0.2}' http://localhost:3001/deposit

Withdrawal related

Create withdrawal

Create a new withdrawal.

Parameter
Name Type Required Description
blkNum Integer Yes The position of the UTXO user wants to withdraw
txIndex Integer Yes The position of the UTXO user wants to withdraw
oIndex Integer Yes The position of the UTXO user wants to withdraw
from Address Yes The owner of the UTXO
Sample
curl -H "Content-type:application/json" --data '{"blkNum": 3, "txIndex": 1, "oIndex": 0, "from": "0xC973531975B1EE371164DCcB9529b89A7bCD1c4A"}' http://localhost:3001/withdraw/create

Challenge withdrawal

Create a withdrawal challenge.

Parameter
Name Type Required Description
withdrawalId Integer Yes The withdrawal ID user wants to challenge
blkNum Integer Yes The position of the UTXO user wants to challenge
txIndex Integer Yes The position of the UTXO user wants to challenge
oIndex Integer Yes The position of the UTXO user wants to challenge
from Address Yes The owner of the UTXO 
curl -H "Content-type:application/json" --data '{"withdrawalId": 4000000000, "blkNum": 4, "txIndex": 2, "oIndex": 1, "from": "0xC973531975B1EE371164DCcB9529b89A7bCD1c4A"}' http://localhost:3001/withdraw/challenge

Finalize withdrawal

Finalize withdrawals manually.

Parameter
Name Type Required Description
from Address Yes Who initiates the withdrawal finalization
Sample
curl -H "Content-type:application/json" --data '{"from": "0xC973531975B1EE371164DCcB9529b89A7bCD1c4A"}' http://localhost:3001/withdraw/finalize