Nano-Ethereum-Signer

If your application needs to sign and verify messages from Ethereum accounts, you need to include a library such as web3, ethereumjs or ethers.js, which increase the size of your builds by 300kb to 1mb+, which is wasteful if you just want signing functionality. As such, I made this library by aggressively, manually pruning dead code and branches. The result is a 52K file with Ethereum signing and verification functionality, which is the smallest I could get so far. Further optimizations may include replacing BN by native BitInt and more prunings.

Installing

npm i nano-ethereum-signer

Functions

// Gets an Ethereum address from a Private Key
ethsig.addressFromKey(private_key : Hex) : Hex

// Signs the hash of a message
ethsig.signMessage(message : Hex, private_key : Hex) : Hex

// Given the hash of a message and signature,
// returns the signer address
ethsig.signerAddress(message : Hex, signature : Hex) : Hex

// Converts an address to the checksum format
ethsig.addressChecksum(address : Hex)

// Keccak256 of a string or array of bytes. If the string
// starts with `0x`, it is interpreted as data. Otherwise,
// it is interpreted as UTF-8. If you want to always use
// UTF-8, pass an extra `true` argument. 
ethsig.keccak(message : String | Array<Uint8>) : Hex

Here, Hex is a string on the format "0x1234abcd...". Private keys and hashes have 256 bits (64 hex digits). Addresses have 160 bits (40 hex digits). Signatures have 520 bits (130 hex digits).

Disclaimer

This is still a WIP: it needs test cases and a LICENSE, and there are still improvements to be made. If possible, we should compile a C implementation with WASM instead. If anyone is willing to start such a project I'd be glad to contribute.