🙌 Introduction

Ethereum user authentication tokens

!Build status
!npm bundle size

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eth-auth is a secure npm library for password-less user authentication on node.js decentralized applications (dApps) by signing an outwardly unpredictable dynamic JWT token with the user's Ethereum private key.

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* Decentralised (Web3)
* Anonymous - User identity covered to dApp governors and the rest of the world.
* Password-less - Your Ethereum private key is your password, and it won't reveal to anyone.
* Breach-less - According to the eth-auth authentication architecture, no need to store meaningful user data in a database.

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✅ Installation

Add eth-auth as a dependency to your project.

``bash
npm install ethauth-server
`
`bash
yarn add ethauth-server
`
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😎 Setup

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As the step one, the Frontend should fetch the Ethereum singing key (JWT) from the backend.
#### Function
`javascript
const ethAuth = require('ethauth-server');
let key = ethAuth.generate("ETHEREUM_ADDRESS", "ETH_AUTH_SECRET");
`


#### Code sample (Express.js)

` javascript
const express = require('express')
const app = express()
const ethAuth = require('ethauth-server');

app.get('/get/:address', (req, res) => {
let address = req.params.address;
let key = ethAuth.generate(address, "ETH_AUTH_SECRET");
res.status(200).json(key: key);
})
`

#### Sample output
`json
{
"key": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJuYW1lIjoiZXRoLWF1dGggdG9rZW4iLCJhZGRyZXNzIjoiMHg5ZUMyODVFZUMxODhGMEViRmE5Zjg4RGE0ODA3YkU1YjA0OWZjMDQ5IiwicmFuZG9tVG9rZW4iOiJaTFRuMk1URkJnWndCNWJGQ3l3MnZMWHdPTFFIejBCQiIsImlhdCI6MTY2MjE3OTkwOH0.uQIG0MnYdJ2jcXQQdxtBy78DtjBZSArqFfsZ3uP6H4Ijson"
}
`
use ether.js library to sign the fetched signing key in your frontend.

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As the second step, We have to verify the Ethrerum signature from the backend.

#### Function
`javascript
const ethAuth = require('ethauth-server');
ethAuth.validate(key, signature, "ETH_AUTH_SECRET")
`

#### Code sample (Express.js)

`javascript
const express = require('express')
const app = express()
const ethAuth = require('ethauth-server');

app.post('/send', (req, res, next) => {
let key = req.body.key;
let signature = req.body.signature;

ethAuth.validate(key, signature, "ETH_AUTH_SECRET").then((validation) => {
res.status(200).json(validation); // true
}).catch((err) => {
res.status(401).send('Unauthorized: Invalid signature');
});

})
`

✅ Authorized response
`json
{
true
}
`
⛔️ Unauthorized response
`
Unauthorized: Invalid signature
``
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Credits

Initial developer: Nilvin Sathnindu Kottage (bysatha.com)
\
Email: hello@bysatha.com
\
Twitter: @sathnindu
\
GitHub: @sathninduk

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License

MIT