I was working on a project recently that required unique API keys to be generated for clients connecting to the server. For various reasons, I settled on the style of license key you commonly see for software packages. You know, the kind you always had to read off the back of a CD case and type in when installing the application. Like
H8OV7-HNTB5-JLLOH-W8FG2
.Jan 22, 2008 Macrovision's FlexNet Operations Removes Manual Mayhem from License Generation and Activation Enhanced activation lowers support costs for software producers, increases customer satisfaction with an improved end-to-end entitlement and licensing experience.
![Software Software](/uploads/1/2/6/4/126438602/446975045.jpg)
Electronic email fulfillment of ordered items and on-line self service generation of license activation keys. This document explains product license activation keys, Juniper’s related ordering, electronic fulfillment and key generation processes. It presents what a customer should expect. A “License Key” Explained. The License Name field, on the Advanced tab, lets you select which data point from the order details (if any) should be factored into license key generation via the name variable. Not Name Based - If the license key generation does not take any name into consideration, select this option.
There are multiple techniques to develop key based software activation. Mostly, you can classify them into offline and online approaches. Offline activation is simple to implement. As you might have guessed, it is merely effective these days. WHITE PAPER Software Licensing and Entitlement Management: The Next Generation Sponsored by: Flexera Software. Amy Konary October 2009 IDC OPINION As the software industry evolves, software producers, high-tech manufacturers, and enterprises are becoming more focused on improving the management of their software license assets.
It’s fairly easy to write such a function. The basic idea is to loop around four times—once for each segment—and have a nested loop that runs five times, picking a random character each time. Here’s what I came up with:
The
$tokens
string contains the characters that are valid in the key, so the loop can pick from it. The $segment_chars
and $num_segments
variables are the number of characters in a segment and the number of segments in the key, respectively. $key_string
is an empty string that the loop will add the characters into.The first for loop runs four times, assuming the desired result is four segments in the key. The inner loop picks a character out of
$tokens
at random each time it goes around. (PHP strings are also arrays, with the each character having its own numerical offset.) The characters are tacked onto the $segment
string.Then the segment is joined with the
$key_string
, and a dash character is applied if the loop isn’t on the final segment yet. End result: something like H8OV7-HNTB5-JLLOH-W8FG2
.![License Key Generation Software Fulfillment License Key Generation Software Fulfillment](/uploads/1/2/6/4/126438602/788384750.png)
Now how can you make sure the key is unique when it’s generated?
License Key Generation Software Fulfillment Program
You generate a new key string with the function, check to see if it exists in your database, and lather/rinse/repeat until that is no longer the case. Usually you won’t have collisions too often, so it will only need to run once. I’m too lazy to figure out the probability, but considering there are 52,521,875 possible combinations for one 5-character segment…you’re probably not going to run into performance issues anytime soon. And if you do, just add another segment onto your key strings.