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2fa

(★ 168)

Node.js TOTP + HOTP library, with nice utilities for handing 2FA

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- 2FA.js
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package.json
README.md

# Installation Guide

1. Get the code

git clone https://github.com/simontabor/2fa

Downloads the entire project code from GitHub to your computer.

cd 2fa

Moves into the project folder you just downloaded.

2. Node.js

Easy Recommended

Prerequisites

Git Needed to download the project code from GitHub.
Node.js Node.js must be installed to use npm. The LTS version is recommended.

npm install --save 2fa

Downloads and installs the libraries listed in package.json.

✅ After running the command, open the address shown in the terminal (usually something like http://localhost:3000) in your browser.

Pulled directly from this repo's README.

// repository documentation

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# 2FA

[![Dependencies](https://david-dm.org/simontabor/2fa.svg)](https://david-dm.org/simontabor/2fa)
[![Join the chat at https://gitter.im/simontabor/2fa](https://img.shields.io/badge/gitter-join%20chat-blue.svg)](https://gitter.im/simontabor/2fa)

[![NPM](https://nodei.co/npm/2fa.png?downloads=true&downloadRank=true&stars=true)](https://www.npmjs.com/package/2fa)

Module for generating and verifying 2FA codes (specifically TOTP and HOTP).

Also contains utilities for handing 2FA logic, such as generating Google Authenticator compatible QR codes (without going via Google Charts) and generating backup codes.

## Install
```
npm install --save 2fa
```

## Usage

```js
var tfa = require('2fa');

// lets generate a new key for a user
// tfa.generateKey(length (optional), cb)
tfa.generateKey(32, function(err, key) {
  // crypto secure hex key with 32 characters

// generate crypto-secure backups codes in a user-friendly pattern
  // tfa.generateBackupCodes(num, pattern (optional), cb)
  tfa.generateBackupCodes(8, 'xxxx-xxxx-xxxx', function(err, codes) {
    // [ '7818-b7b8-c928', '3526-dc04-d3f2', 'be3c-5d9f-cb68', ... ]

// these should be sent to the user, stored and checked when we get a 2fa code
  });

// generate a google QR code so the user can save their new key
  // tfa.generateGoogleQR(name, accountname, secretkey, cb)
  tfa.generateGoogleQR('Company', 'email@gmail.com', key, function(err, qr) {
    // data URL png image for google authenticator
  });

var opts = {
    // the number of counters to check before what we're given
    // default: 0
    beforeDrift: 2,
    // and the number to check after
    // default: 0
    afterDrift: 2,
    // if before and after drift aren't specified,
    // before + after drift are set to drift / 2
    // default: 0
    drift: 4,
    // the step for the TOTP counter in seconds
    // default: 30
    step: 30
  };

// calculate the counter for the HOTP (pretending it's actually TOTP)
  var counter = Math.floor(Date.now() / 1000 / opts.step);

// generate a valid code (in real-life this will be user-input)
  var code = tfa.generateCode(key, counter);

// verify it as a HOTP
  var validHOTP = tfa.verifyHOTP(key, code, counter, opts);
  // true

// for TOTP, the counter is calculated internally using Date.now();
  var validTOTP = tfa.verifyTOTP(key, code, opts);
  // true

});
```