micro-eth-signer

micro-eth-signer

Create, sign and validate Ethereum transactions & addresses with minimum deps.

Library's size is 4.7KB minified. Uses three dependencies (SHA-3, RLP & secp256k1), all libraries combined are 12KB gzipped.

Usage

npm install micro-eth-signer

Supports Node.js & all major browsers. If you're looking for a fully-contained single-file version, check out Releases page on GitHub.

const { Address, Transaction } = require('micro-eth-signer');

(async () => {
  const tx = new Transaction({
    to: '0xdf90dea0e0bf5ca6d2a7f0cb86874ba6714f463e',
    gasPrice: 100n * 10n ** 9n, // 100 gwei in wei
    value: 10n ** 18n, // 1 eth in wei
    nonce: 1
  });
  const privateKey = '6b911fd37cdf5c81d4c0adb1ab7fa822ed253ab0ad9aa18d77257c88b29b718e';
  const signedTx = await tx.sign(privateKey); // Uint8Array is also accepted
  const {hash, hex} = signedTx;

  // Strings can be used also
  // tx = new Transaction({"nonce": "0x01"})
  // Same goes to serialized representation
  // tx = new Transaction('0xeb018502540be40082520894df90dea0e0bf5ca6d2a7f0cb86874ba6714f463e872386f26fc1000080808080');

  // Various tx properties
  console.log('Need wei', tx.upfrontCost); // also, tx.fee, tx.amount, tx.sender, etc
  
  // Address manipulation
  const addr = Address.fromPrivateKey(privateKey);
  const pubKey = signedTx.recoverSenderPublicKey();
  console.log('Verified', Address.verifyChecksum(addr));  
  console.log('addr is correct', signedTx.sender, signedTx.sender == addr);
  console.log(signedTx);
})();

API

Address

Represents ETH address and has following methods:

• Address.fromPrivateKey(privateKey: string | Uint8Array): string - create address from private key
• Address.fromPublicKey(publicKey: string | Uint8Array): string - creates address from public key
• Address.checksum(nonChecksummedAddress: string): string - creates checksummed address from non-checksummed address
• Address.verifyChecksum(address: string): boolean - verifies checksummed & non-checksummed address

Usage:

const addr = "0x0089d53f703f7e0843953d48133f74ce247184c2";
const addrc = Address.checksum(addr) // 0x0089d53F703f7E0843953D48133f74cE247184c2
Address.verifyChecksum(addrc) // true
Address.verifyChecksum(addr) // true also (non-checksummed)
Address.fromPrivateKey("0687640ee33ef844baba3329db9e16130bd1735cbae3657bd64aed25e9a5c377")
  // 0xD4fE407789e11a27b7888A324eC597435353dC35
Address.fromPublicKey("030fba7ba5cfbf8b00dd6f3024153fc44ddda93727da58c99326eb0edd08195cdb")
  // 0xD4fE407789e11a27b7888A324eC597435353dC35

Transaction

Represents unsigned & signed ETH transactions. They are serialized & deserialized using RLP. Here's an example of the same transaction in raw state, and serialized state:

// raw
{
  "nonce": "0x01", "gasLimit": "0x5208", "gasPrice": "0x02540be400",
  "to": "0xdf90dea0e0bf5ca6d2a7f0cb86874ba6714f463e",
  "value": "2386f26fc10000", "data": "0x"
}
// serialized
"0xeb018502540be40082520894df90dea0e0bf5ca6d2a7f0cb86874ba6714f463e872386f26fc1000080808080"

You can use either of those to initialize new Transaction. There are a few methods available:

• new Transaction(serialized[, chain, hardfork]) - creates transaction from Raw TX string.
  • chain: optional argument (default is mainnet; ropsten, rinkeby, goerli, kovan etc)
  • hardfork: optional argument (default is berlin). The only place we're checking for hardfork is the replay protection code. There are very old transactions that don't support replay protection, you'll probably won't need them
• new Transaction(rawTx[, chain, hardfork]) - creates transaction from Raw TX data.
  • rawTx must have fields to, value, nonce, gasPrice, gasLimit
  • It could optionally specify data
  • to is recipient's address
  • value is amount to send in wei
  • nonce is sender's nonce in number
  • gasLimit is transaction's Gas Limit in wei (minimum is 21000)
  • gasPrice is transaction's Gas Price in wei (100 gwei is 100 * 10 ** 9)
  • data is transaction's data if it's calling some smart contracts
• Transaction#sign(privateKey: string | Uint8Array): Promise<Transaction> — creates new transaction with same data, but signed by following private key
• Transaction#recoverSenderPublicKey(): string — recovers sender's public key from signed transaction

Transaction Properties

• isSigned: boolean - whether tx is signed with private key
• amount: bigint - amount (aka value) in wei
• fee: bigint - fee in wei (gasLimit * gasPrice)
• upfrontCost: bigint - amount + fee in wei, combined
• to: string - address that receives the tx
• nonce: number - account's nonce
• sender: string - address that sends the tx. Only signed txs have the field
• hash: string - signed tx hash used in block explorers. Example: 50b6e7b58320c885ab7b2ee0d0b5813a697268bd2494a06de792790b13668c08
• raw: Object - raw transaction's data with fields encoded as strings

License

MIT License

Copyright (c) 2021 Paul Miller (https://paulmillr.com)