# eth-sig-util

> A few useful functions for signing ethereum data

Latest version **3.0.1** (published 2021-02-05) · ISC license · 0 weekly downloads

> **Deprecated.** This package is deprecated.

## Install

```sh
npm install eth-sig-util
pnpm add eth-sig-util
yarn add eth-sig-util
bun add eth-sig-util
```

## Health

**Score 10/100 (F)** — status: deprecated.

Negative: deprecated.

## Facts

| | |
|---|---|
| Version | 3.0.1 |
| Published | 2021-02-05 |
| First published | 2017-02-21 |
| Weekly downloads | 0 |
| License | ISC |
| TypeScript types | separate (@types/eth-sig-util) |
| Module format | CommonJS |
| Dependencies | 4 |
| Unpacked size | 50.6 KB |
| Known vulnerabilities | 0 |
| Install scripts | no |
| GitHub stars | 583 |
| Author | Dan Finlay |
| Maintainers | danfinlay, kumavis, rekmarks, estebanmino, metamaskbot, gudahtt |
| Keywords | ethereum, signature |

## Links

- npm: https://www.npmjs.com/package/eth-sig-util
- Repository: https://github.com/MetaMask/eth-sig-util
- Homepage: https://github.com/MetaMask/eth-sig-util#readme
- Issues: https://github.com/MetaMask/eth-sig-util/issues
- npm.io page: https://npm.io/package/eth-sig-util

## Dependencies (4)

- [tweetnacl](https://npm.io/package/tweetnacl.md) ^1.0.3
- [ethereumjs-abi](https://npm.io/package/ethereumjs-abi.md) ^0.6.8
- [tweetnacl-util](https://npm.io/package/tweetnacl-util.md) ^0.15.0
- [ethereumjs-util](https://npm.io/package/ethereumjs-util.md) ^5.1.1

## Recent versions

- 3.0.1 (latest) — 2021-02-05
- 2.5.4 — 2021-02-04
- 3.0.0 — 2020-11-09
- 2.5.3 — 2020-03-16
- 2.5.2 — 2019-11-30
- 2.5.1 — 2019-11-21
- 2.5.0 — 2019-10-21
- 2.4.4 — 2019-08-30
- 2.4.3 — 2019-08-28
- 2.4.2 — 2019-08-27
- 2.4.1 — 2019-08-27
- 2.4.0 — 2019-08-25
- 2.3.0 — 2019-07-16
- 2.2.0 — 2019-05-28
- 2.1.2 — 2019-03-19
- … 15 more at https://npm.io/package/eth-sig-util/versions

## README

# Eth-Sig-Util [![CircleCI](https://circleci.com/gh/MetaMask/eth-sig-util.svg?style=svg)](https://circleci.com/gh/MetaMask/eth-sig-util)

A small collection of ethereum signing functions.

You can find usage examples [here](https://github.com/danfinlay/js-eth-personal-sign-examples)

[Available on NPM](https://www.npmjs.com/package/eth-sig-util)

## Installation

```shell
npm install eth-sig-util --save
```

## Methods

### concatSig(v, r, s)

All three arguments should be provided as buffers.

Returns a continuous, hex-prefixed hex value for the signature, suitable for inclusion in a JSON transaction's data field.

### normalize(address)

Takes an address of either upper or lower case, with or without a hex prefix, and returns an all-lowercase, hex-prefixed address, suitable for submitting to an ethereum provider.

### personalSign (privateKeyBuffer, msgParams)

msgParams should have a `data` key that is hex-encoded data to sign.

Returns the prefixed signature expected for calls to `eth.personalSign`.

### recoverPersonalSignature (msgParams)

msgParams should have a `data` key that is hex-encoded data unsigned, and a `sig` key that is hex-encoded and already signed.

Returns a hex-encoded sender address.

### signTypedData (privateKeyBuffer, msgParams)

Signs typed data as per [an early draft of EIP 712](https://github.com/ethereum/EIPs/pull/712/commits/21abe254fe0452d8583d5b132b1d7be87c0439ca).

Data should be under `data` key of `msgParams`. The method returns prefixed signature.

### signTypedData_v3 (privateKeyBuffer, msgParams)

Signs typed data as per the published version of [EIP 712](https://github.com/ethereum/EIPs/pull/712).

Data should be under `data` key of `msgParams`. The method returns prefixed signature.

### signTypedData_v4 (privateKeyBuffer, msgParams)

Signs typed data as per an extension of the published version of [EIP 712](https://github.com/MetaMask/eth-sig-util/pull/54).

This extension adds support for arrays and recursive data types.

Data should be under `data` key of `msgParams`. The method returns prefixed signature.

### recoverTypedSignature ({data, sig})

Return address of a signer that did `signTypedData`.

Expects the same data that were used for signing. `sig` is a prefixed signature.

### recoverTypedSignature_V4 ({data, sig})

Return address of a signer that did `signTypedData` as per an extension of the published version of [EIP 712](https://github.com/MetaMask/eth-sig-util/pull/54).

This extension adds support for arrays and recursive data types.

Expects the same data that were used for signing. `sig` is a prefixed signature.

### typedSignatureHash (typedData)

Return hex-encoded hash of typed data params according to [EIP712](https://github.com/ethereum/EIPs/pull/712) schema.

### extractPublicKey (msgParams)

msgParams should have a `data` key that is hex-encoded data unsigned, and a `sig` key that is hex-encoded and already signed.

Returns a hex-encoded public key.

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_Source: https://npm.io/package/eth-sig-util · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._