Time-based (TOTP) and HMAC-based (HOTP) One-Time Password library
- About
- Features
- Quick Start
- Migration Guide
- Getting Started
- Available Options
- Available Packages
- Appendix
- Contributors
- License
otplib is a JavaScript One Time Password (OTP) library for OTP generation and verification.
It implements both HOTP - RFC 4226
and TOTP - RFC 6238,
and are tested against the test vectors provided in their respective RFC specifications.
These datasets can be found in the packages/tests-data folder.
This library is also compatible with Google Authenticator, and includes additional methods to allow you to work with Google Authenticator.
- Typescript support
- Class interfaces
- Function interfaces
- Async interfaces
- Pluggable modules (crypto / base32)
crypto (node)crypto-js@ronomon/crypto-asyncthirty-twobase32-encode+base32-decode
- Presets provided
browserdefault (node)default-async (same as default, but with async methods)v11 (adapter for previous version)
References:
npm install otplib thirty-twoimport { authenticator } from 'otplib/preset-default';
const secret = 'KVKFKRCPNZQUYMLXOVYDSQKJKZDTSRLD';
// Alternative: const secret = authenticator.generateSecret();
const token = authenticator.generate(secret);
try {
const isValid = authenticator.check(token, secret);
// or
const isValid = authenticator.verify({ token, secret });
} catch (err) {
// Possible errors
// - options validation
// - "Invalid input - it is not base32 encoded string" (if thiry-two is used)
console.error(err);
}The browser preset is a self contained umd module with Buffer split out as an external dependency.
As such, there are 2 scripts required: preset-browser/index.js and preset-browser/buffer.js.
<script src="https://unpkg.com/otplib@^12.0.0/preset-browser/buffer.js"></script>
<script src="https://unpkg.com/otplib@^12.0.0/preset-browser/index.js"></script>
<script type="text/javascript">
// window.otplib.authenticator
// window.otplib.hotp
// window.otplib.totp
</script>The buffer.js provided by this library is a cached copy
from https://www.npmjs.com/package/buffer.
You can also download and include the latest version via their project page.
In the above example, we are directly using the scripts hosted by unpkg.com.
You can also npm install otplib and get a copy from the node_modules/otplib/preset-browser folder.
This library follows semver. As such, major version bumps usually mean API changes or behavior changes.
Please check upgrade notes for more information,
especially before making any major upgrades.
Check out the release notes associated with each tagged versions in the releases page.
v12.x is a huge architectural and language rewrite. Please check out the docs if you are migrating. A preset adapter is available to provide methods that behave like
v11.xofotplib.
Link to v11.x README.md and v11.x API Docs.
// Update
import { authenticator } from 'otplib'; // v11.x
// to
import { authenticator } from 'otplib/preset-v11';
// There should be no changes to your current code.
// However, deprecated or modified class methods will have console.warn.This is a more in-depth setup guide for installing, configuring and customising your dependencies for the library.
Check out the Quick Start guide if you do need / want to customise any dependencies from the presets.
npm install otplib| Release Type | Version | Command |
|---|---|---|
| Current / Stable | |
npm install otplib |
| Release Candidate |  |
npm install otplib@next |
The crypto modules are used to generate the digest used to derive the OTP tokens from.
By default, Node.js has inbuilt crypto functionality, but you might want to replace it
for certain environments that do not support it.
Currently out-of-the-box, there are some Crypto Plugins included. Install the dependencies for one of them.
# Choose either
# Node.js crypto (you don't need to install anything else - http://nodejs.org/api/crypto.html)
# or
npm install crypto-jsIf you're using Google Authenticator, you'll need a base32 module for encoding and decoding your secrets.
Currently out-of-the-box, there are some Base32 Plugins included. Install the dependencies for one of them.
# Choose either
npm install thirty-two
# or
npm install base32-encode base32-decodeimport { HOTP, TOTP, Authenticator } from 'otplib';
// Base32 Plugin
// for thirty-two
import { keyDecoder, keyEncoder } from 'otplib/plugin-thirty-two';
// for base32-encode and base32-decode
import { keyDecoder, keyEncoder } from 'otplib/plugin-base32-enc-dec';
// Crypto Plugin
// for node crypto
import { createDigest, createRandomBytes } from 'otplib/plugin-crypto';
// for crypto-js
import { createDigest, createRandomBytes } from 'otplib/plugin-crypto-js';
// Setup an OTP instance which you need
const hotp = new HOTP({ createDigest });
const totp = new TOTP({ createDigest });
const authenticator = new Authenticator({
createDigest,
createRandomBytes,
keyDecoder,
keyEncoder
});
// Go forth and generate tokens
const token = hotp.generate(YOUR_SECRET, 0);
const token = totp.generate(YOUR_SECRET);
const token = authenticator.generate(YOUR_SECRET);Alternatively, if you are using the functions directly instead of the classes, pass these as options into the functions.
import {
hotpOptions,
hotpToken,
totpOptions,
totpToken,
authenticatorOptions,
authenticatorToken
} from 'otplib/core';
// As with classes, import your desired Base32 Plugin and Crypto Plugin.
// import ...
// Go forth and generate tokens
const token = hotpToken(YOUR_SECRET, 0, hotpOptions({ createDigest));
const token = totpToken(YOUR_SECRET, totpOptions({ createDigest));
const token = authenticatorToken(YOUR_SECRET, authenticatorOptions({
createDigest,
createRandomBytes,
keyDecoder,
keyEncoder
));All instantiated classes will have their options inherited from their respective options
generator. i.e. HOTP from hotpOptions, TOTP from totpOptions
and Authenticator from authenticatorOptions.
All OTP classes have an object setter and getter method to override these default options.
For example,
import { authenticator } from 'otplib/preset-default';
// setting
authenticator.options = {
step: 30,
window: 1
};
// getting
const opts = authenticator.options;
// reset to default
authenticator.resetOptions();
// getting all options, with validation
// and backfilled with library defaults
const opts = authenticator.allOptions();| Option | Type | Description |
|---|---|---|
| algorithm | string | The algorithm used for calculating the HMAC. |
| createDigest | function | Creates the digest which token is derived from. |
| createHmacKey | function | Formats the secret into a HMAC key, applying transformations (like padding) where needed. |
| digest | string | USE WITH CAUTION. Same digest = same token. Used in cases where digest is generated externally. (eg: async use cases) |
| digits | integer | The length of the token. |
| encoding | string | The encoding that was used on the secret. |
// HOTP defaults
{
algorithm: 'sha1'
createDigest: undefined, // to be provided via a otplib-plugin
createHmacKey: hotpCreateHmacKey,
digits: 6,
encoding: 'ascii',
}Note: Includes all HOTP Options
| Option | Type | Description |
|---|---|---|
| epoch | integer | USE WITH CAUTION. Same epoch = same token. Starting time since the UNIX epoch (seconds). Epoch is JavaScript formatted. i.e. Date.now() or UNIX time * 1000 |
| step | integer | Time step (seconds) |
| window | integer, [number, number] |
Tokens in the previous and future x-windows that should be considered valid. If integer, same value will be used for both. Alternatively, define array: [past, future] |
// TOTP defaults
{
// ...includes all HOTP defaults
createHmacKey: totpCreateHmacKey,
epoch: Date.now(),
step: 30,
window: 0,
}Note: Includes all HOTP + TOTP Options
| Option | Type | Description |
|---|---|---|
| createRandomBytes | function | Creates a random string containing the defined number of bytes to be used in generating a secret key. |
| keyEncoder | function | Encodes a secret key into a Base32 string before it is sent to the user (in QR Code etc). |
| keyDecoder | function | Decodes the Base32 string given by the user into a secret. |
// Authenticator defaults
{
// ...includes all HOTP + TOTP defaults
encoding: 'hex',
createRandomBytes: undefined, // to be provided via a otplib-plugin
keyEncoder: undefined, // to be provided via a otplib-plugin
keyDecoder: undefined, // to be provided via a otplib-plugin
}The following options are modified for functions and classes which are postfixed with Async.
eg: AuthenticatorAsync, totpDigestAsync, hotpTokenAsync etc.
| Option | Type | Output |
|---|---|---|
| createDigest | async function | function returns Promise<string> instead of string |
| createHmacKey | async function | function returns Promise<string> instead of string |
| createRandomBytes | async function | function returns Promise<string> instead of string |
| keyEncoder | async function | function returns Promise<string> instead of string |
| keyDecoder | async function | function returns Promise<string> instead of string |
This library has been split into 3 categories: core, plugin and preset.
Provides the core functionality of the library. Parts of the logic has been separated out in order to provide flexibility to the library via available plugins.
| file | description |
|---|---|
| otplib/hotp | HOTP functions + class |
| otplib/hotp | TOTP functions + class |
| otplib/authenticator | Google Authenticator functions + class |
| otplib/core | Aggregates hotp/totp/authenticator functions + class |
| file | description |
|---|---|
| otplib/hotp-async | async version of otplib/hotp |
| otplib/hotp-async | async version of otplib/hotp |
| otplib/authenticator-async | async version of otplib/authenticator |
| otplib/core-async | async version of otplib/core |
| plugin | type | depends on |
|---|---|---|
| otplib/plugin-crypto | sync | crypto (included in Node.js) |
| otplib/plugin-crypto-js | sync | npm install crypto-js |
| otplib/plugin-crypto-async-ronomon | async | npm install @ronomon/crypto-async |
These crypto plugins provides:
{
createDigest, // used for token derivation
createRandomBytes, //used to generate random keys for Google Authenticator
}| plugin | type | depends on |
|---|---|---|
| otplib/plugin-thirty-two | sync | npm install thirty-two |
| otplib/plugin-base32-enc-dec | sync | npm install base32-encode base32-decode |
These Base32 plugins provides:
{
keyDecoder, //for decoding Google Authenticator secrets
keyEncoder, // for encoding Google Authenticator secrets.
}Presets are preconfigured HOTP, TOTP, Authenticator instances to allow you to get started with the library quickly.
Each presets would need the corresponding dependent npm modules to be installed.
| file | depends on | description |
|---|---|---|
| otplib/preset-default | npm install thirty-two |
|
| otplib/preset-default-async | npm install thirty-two @ronomon/crypto-async |
async version of otplib/preset-default |
| otplib/preset-browser | See Browser Compatibility | Webpack bundle and is self contained. |
| otplib/preset-v11 | npm install thirty-two |
Wrapper to adapt the APIs to v11.x compatible format |
TypeScript support was introduced in v10.0.0, which added type definitions over .js files.
As of v12.0.0, the library has been re-written in Typescript from the ground up.
async support was introduced in v12.0.0.
This was added as some libraries like expo.io or even the browser API (window.Crypto.subtle) started providing only async methods.
There are 2 was to use async - using async replacements, or handling digests separately.
This is the simplest way to get started. Other than allOptions() and resetOptions,
all other methods are converted to async and thus needs to be Promise.resolve or await.
eg: await .generate(...), await .check(...)
import { AuthenticatorAsync } from 'otplib/core-async';
const authenticator = new AuthenticatorAsync({
// ...options
// make sure you use async versions of
// required functions like createDigest.
});
// Note: await needed as all methods are async
const token = await authenticator.generate(secret);In this method, you would essentially take over the digest generation, leaving the library to handle the digest to token conversion.
import { Authenticator } from 'otplib/core';
import { authenticatorDigestAsync } from 'otplib/authenticator-async';
// This is a synchronous Authenticator class.
const authenticator = new Authenticator({
// ...options
});
// Override the digest generation.
const digest = await authenticatorDigestAsync(secret, {
...authenticator.allOptions(),
createDigest: async (algorithm, hmacKey, counter) => 'string'; // put your async implementation
});
authenticator.options = { digest };
const token = authenticator.generate(secret);
// recommended: reset to remove the digest.
authenticator.resetOptions();
// reference test in: ./packages/tests-builds/example.test.jsCheck the API Documentation for the full list of async functions.
otplib/preset-browser is a umd bundle with some node modules replaced to reduce the browser size.
The following defaults have been used:
- crypto:
crypto-js - encoder:
base32-encode - decoder:
base32-decode
To see what is included, you can take a look at packages/otplib-browser/index.ts.
The approximate bundle sizes are as follows:
| Bundle Type | Size |
|---|---|
| original | 324KB |
| original, minified + gzipped | 102KB |
| optimised | 30.9KB |
| optimised, minified + gzipped | 9.53KB |
Paired with the gzipped browser buffer.js module, it would be about 7.65KB + 9.53KB = 17.18KB.
In RFC 6238, the secret / seed length for different algorithms are predefined:
HMAC-SHA1 - 20 bytes
HMAC-SHA256 - 32 bytes
HMAC-SHA512 - 64 bytesAs such, the length of the secret provided (after any decoding) will be padded and sliced according to the expected length for respective algorithms.
The default encoding option has been set to hex (Authenticator) instead of ascii (TOTP).
Note: RFC4648 obseletes RFC 3548. Any encoders following the newer specifications will work.
Google Authenticator requires keys to be base32 encoded. It also requires the base32 encoder to be RFC 3548 compliant.
OTP calculation will still work should you want to use other base32 encoding methods (like Crockford's Base32) but it will NOT be compatible with Google Authenticator.
const secret = authenticator.generateSecret(); // base32 encoded hex secret key
const token = authenticator.generate(secret);You may want to generate and display a QR Code so that users can scan
instead of manually entering the secret. Google Authenticator and similar apps
take in a QR code that holds a URL with the protocol otpauth://,
which you get from authenticator.keyuri.
Google Authenticator will ignore the algorithm, digits, and step options.
See the keyuri documentation
for more information.
If you are using a different authenticator app, check the documentation for that app to see if any options are ignored, which will result in invalid tokens.
While this library provides the "otpauth" uri, you'll need a library to generate the QR Code image.
An example is shown below:
// npm install qrcode
import qrcode from 'qrcode';
import { authenticator } from 'otplib/preset-default';
const user = 'A user name, possibly an email';
const service = 'A service name';
// v11.x.x and above
const otpauth = authenticator.keyuri(user, service, secret);
// v10.x.x and below
const otpauth = authenticator.keyuri(
encodeURIComponent(user),
encodeURIComponent(service),
secret
);
qrcode.toDataURL(otpauth, (err, imageUrl) => {
if (err) {
console.log('Error with QR');
return;
}
console.log(imageUrl);
});Note: For versions
v10.x.xand below,keyuridoes not URI encodeuserandservice. You'll need to do so before passing in the parameteres.
Helper methods for getting the remaining time and used time within a validity period
of a totp or authenticator token were introduced in v10.0.0.
authenticator.timeUsed(); // or totp.timeUsed();
authenticator.timeRemaining(); // or totp.timeRemaining();
// The start of a new token would be when:
// - timeUsed() === 0
// - timeRemaining() === stepExpo contains modified crypto implmentations targeted at the platform.
While otplib does not provide an expo specified package, with the re-architecture
of otplib, you can now provide an expo native createDigest to the library.
Alternatively, you can make use of crypto provided by otplib/plugin-crypto-js or
the bundled browser umd module otplib/preset-browser.
Pull Requests are much welcomed for a native expo implementation as well.
If you'll like to explore the library with local-repl you can do so as well.
$ npm install
$ npm run build
$ npx local-repl
# You should see something like:
# Node v8.9.4, local-repl 4.0.0
# otplib 10.0.0
# Context: otplib
# [otplib] >
$ [otplib] > secret = 'KVKFKRCPNZQUYMLXOVYDSQKJKZDTSRLD'
$ [otplib] > otplib.authenticator.generate(secret)Thanks goes to these wonderful people (emoji key):
 Gerald Yeo 💻 📖 🚧 |
 Oliver Schneider 📖 |
 Marc-Aurèle DARCHE 📖 |
 Ahmed Hamdy (@shakram02) 📖 |
 Tony Brix 💻 📖 |
This project follows the all-contributors specification. Contributions of any kind welcome!
otplib is MIT licensed
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