Create Auth Tokens with PHP

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()
5. pakainfo

   Sound is great!!!

   It can be done either way, and values in a GET request aren’t really any more visible than values in a POST request. If anybody can “see” (i.e. intercept) the request, he can see everything you’re sending. In the end an HTTP request is just a bunch of HTTP headers possibly followed by a body. The URL is send in the first GET /foo/bar HTTP/1.1 line, other values are just send in different, following lines.

   So it’s up to you where you expect your authentication token to be send. You can require it to be a query parameter that is appended to every request:

   GET /foo/bar?user=123456&token=abcde…

   To really use the HTTP protocol as intended though, you should use the Authorization HTTP header:

   Authorization: MyScheme 123456:abcde…
   The content of this header is entirely up to you. It usually specifies an authorization method like Basic, followed by whatever you want to require for authentication. This can simply be the username and password, a hash of them, an opaque token the client has obtained at some point or anything else really.

   I’d recommend a token system or a request signing system, with the latter being very much preferred. In a request signing system, the client has to obtain a token from you. It then sends a hash of this token and certain characteristics of the request to authenticate the request, e.g. sha1(Token + Timestamp + Request URL + Request Body). Your server can validate this without the client having to send the token in plain text on each request.