youaresoroman / bsc-eth-bridge

NodeJS Ethereum to Binance Smart Chain bridge

ETH - BSC bridge message signer

Node dependencies

• ethereum-input-data-decoder
• express
• web3
• axios

Web3 Instance and signing

Ethereum provider must be set, Infura API and BSC public RPC used in this example (global constant "InfuraAPI" and "BSCHttpAPI")

Private key must be securely saved (global constants "privateKey*")

Instruction to deploy to AWS

Soon...

Instruction to deploy to Deta

Full istructions how to use deta at https://docs.deta.sh/docs/home/ In this variant you have to take care of privateKey because it is not cyphered!!!

After configuring CLI

Stage 1

Make a new project

deta new --node eth-bsc-bridge
cd eth-bsc-bridge
npm i

Stage 2

Copy index_node.js and package.json to project root then run following command

npm i

Stage 3

Deploy project to Deta

deta deploy

Functions

External

await getTransactionSign(
  transactionHash,
  abiMethodToCheck,
  contractToCheck,
  contractABI,
  privateKey,
  httpAPIURL
)
  .then((result) => {
    // Signed message
  })
  .catch((error) => {
    // Error message
  });

getTransactionSign

---

Checks transaction data to meet defined conditions then signs arbitrary data

Parameters

1. String - The transaction hash.
2. String - The ABI method to check.
3. String - The contract address to check.
4. Object - The ABI object.
5. String - Private key used to sign message.
6. String - The RPC service URL.

Returns

Promise returns Object: The signature object

• message - String: The the given message.
• messageHash - String: The hash of the given message.
• r - String: First 32 bytes of the signature
• s - String: Next 32 bytes of the signature
• v - String: Recovery value + 27

Internal

getTransactionByHash

---

Parameters

1. String - The transaction hash.
2. String - The RPC service URL.

Returns

Promise returns Object - A transaction object its hash transactionHash:

• hash 32 Bytes - String: Hash of the transaction.
• nonce - Number: The number of transactions made by the sender prior to this one.
• blockHash 32 Bytes - String: Hash of the block where this transaction was in. null when its pending.
• blockNumber - Number: Block number where this transaction was in. null when its pending.
• transactionIndex - Number: Integer of the transactions index position in the block. null when its pending.
• from - String: Address of the sender.
• to - String: Address of the receiver. null when its a contract creation transaction.
• value - String: Value transferred in :ref:wei <what-is-wei>.
• gasPrice - String: Gas price provided by the sender in :ref:wei <what-is-wei>.
• gas - Number: Gas provided by the sender.
• input - String: The data sent along with the transaction.

decodeTransactionInput

---

Parameters

1. String - The transaction input.
2. Object - The ABI object.

Returns

Object - A result transaction input decoding :

• method - String: The the given message.
• types - Object: tuples are represented as a string containing types contained in the tuple.
• inputs - Object: tuples are represented as an array containing values contained in the tuple
• names - Object: tuples are represented as an array with 2 items. Item 1 is the name of the tuple, item 2 is an array containing the names of the values contained in the tuple.

checkIfTransactionNotRejected

---

Parameters

1. String - The transaction hash.
2. String - The RPC service URL.

Returns

Promise returns boolean - A result of checking transaction hash transactionHash

getActualETHBlockNumber

---

Parameters

1. String - The RPC service URL.

Returns

Promise returns number - latest block number

checkIfValidContract

---

Parameters

1. String - The contract address from transaction.
2. String - The contract address.

Returns

Promise resolve if address is ok, reject if address is not.

checkIfTransactionValidated

---

Parameters

1. number - The transaction block number.
2. String - The RPC service URL.
3. number - ( Optional ) The minimum amount of transaction to check

Returns

Promise returns boolean - A result of checking minimum amount of confirmations

signMessage

---

Signs arbitrary data

Parameters

1. number - The transaction amount.
2. String - The transaction block number.
3. String - The transaction adress amount send from.
4. String - Private key used to sign message

Returns

Object: The signature object

• message - String: The the given message.
• messageHash - String: The hash of the given message.
• r - String: First 32 bytes of the signature
• s - String: Next 32 bytes of the signature
• v - String: Recovery value + 27