Popular:
 Building Resilient Systems on AWS: Learn how to design and implement a resilient, highly available, fault-tolerant infrastructure on AWS.

Create Auth Tokens with PHP

By  on  

Working with OAuth and similar authentication protocols requires the use of temporary tokens which represent unique handshakes between multiple web services.  These tokens must be unique, securely stored, and the longer, the better.

Since I've been out of the PHP game for a while, I was researching how to create such tokens without additional libraries.  The following snippet does the trick:

// bin2hex(random_bytes($length))
$token = bin2hex(random_bytes(64));

/*
  Examples:

  39e9289a5b8328ecc4286da11076748716c41ec7fb94839a689f7dac5cdf5ba8bdc9a9acdc95b95245f80a00d58c9575c203ceb541507cce40dd5a96e9399f4a
  1c46538c712e9b5bf0fe43d692147004f617b494d004e29daaf33e4528f253db5d911a690856f0b77cfa98103c8231bffff869f179125d17d28e52bfadb9f205
  ...
*/

If you aren't using PHP7 or above, you can fallback to the following:

$token = bin2hex(openssl_random_pseudo_bytes(64));

Having the backing of OpenSSL for token generation gives confidence that the token will be unique.  Of course you can also do a storage check to ensure the token isn't already in use, but if you use a length of 64 or larger, the chances you repeat a token are incredibly slim!

Recent Features

Incredible Demos

  • By
    jQuery Link Nudging

    A few weeks back I wrote an article about MooTools Link Nudging, which is essentially a classy, subtle link animation achieved by adding left padding on mouseover and removing it on mouseout. Here's how to do it using jQuery: The jQuery JavaScript It's important to keep...

  • By
    Link Nudging with CSS3 Animations

    One of the more popular and simple effects I've featured on this blog over the past year has been linking nudging.  I've created this effect with three flavors of JavaScript:  MooTools, jQuery, and even the Dojo Toolkit.  Luckily CSS3 (almost) allows us to ditch...

Discussion

  1. Rafael Corrêa Gomes

    Thanks for sharing!

  2. Valtteri

    I’ve used this, because it’s produces a shorter string:

    $token = base64_encode(random_bytes(64));

// Example:
// yak91pYnDWkaDPEjGAOgGcdTA4ybHF+R+5KVcvgfuoAJz3QMmaxJfBYIkKT9zpSDRE6jfHMW9jahsw1b/aMXtw==

    Usually I replace + and / with - and _, so it doesn’t need encoding anywhere:

    $token = strtr($token, '+/', '-_');
  3. Loz Calver

    A word of advice: don’t use openssl_random_pseudo_bytes() as a fallback for random_bytes() in PHP 5.x, use the random_compat library instead: https://github.com/paragonie/random_compat.

  4. Parth Patel

    Thanks for the trick. How’s the random_compat compared to openssl_random_pseudo_bytes()

Wrap your code in <pre class="{language}"></pre> tags, link to a GitHub gist, JSFiddle fiddle, or CodePen pen to embed!