CODEWITHSUNDEEP
phpserialization
reignsly
reignsly

Reputation: 502

How to generate an Activation Key (or Serial Key)

My problem is this : I have a user id : 0001 And Expiration code : 2015-10-10 12:00

What I need is to encrypt the two value so that I can have some like : TRE-3DR-SER-WER-67J-AX3 (something like this), and also can be decrypted to its original values.

What I did was to jumble the two value, remove spaces and dashes and create a letter or number equivalent to a single character.

My problem is I want the generated kay to be more secure and harder to decode and if possible shorter string.

Upvotes: 0

Views: 4017

Answers (2)

gunwin
gunwin

Reputation: 4832

Encoding:

 $user = "0001"; //Solution only works if this value is always 4 characters.
 $datetime = "2015-10-10 12:00";

 $reps = array("-", " ", ":");
 $unencoded = $user . str_replace($reps, "", $datetime);
 //gives: 001201510101200

 $encoded = strtoupper(base64_encode($unencoded)); 

 //This will always be 20 characters long
 //Result: MDAXMJA5OTK5OTAXMJAW

 $finalCode = substr($encoded, 0, 5) . "-"
              .substr($encoded, 4, 5) . "-"
              .substr($encoded, 9, 5) . "-"
              .substr($encoded, 14, 5) . "-"

 //result: MDAXM-JA5OT-K5OTA-XMJAW

Decode:

 $input = "MDAXM-JA5OT-K5OTA-XMJAW";

 $encoded = str_replace("-", "", $input );
 $decoded = base64_decode($encoded);

 $year = substr($decoded, 4, 4);
 $month = substr($decoded, 8, 2);
 $day = substr($decoded, 10, 2);
 $hour = substr($decoded, 12, 2);
 $min = substr($decoded, 14, 2);

 $userid = substr($decoded, 0, 4);
 $date = new DateTime($year . "-". $month . "-" .$day. " ".$hour.":".$min);

Note: I would not recommend doing this, it is very insecure. I would follow the advice of some of the other answers and keep your code random and seperate to the user ID and date/time.

Upvotes: -1

zanderwar
zanderwar

Reputation: 3730

You should keep the activation key seperate, and irrelevant to expiry date and user ID. It's literally creating a method to decrypt your own keys. Instead; have your table similar to the below.

+----------------------------------------+
|   UserID    |    Key    |    Expiry    |
+----------------------------------------+

Than you can generate the ID:

<?php
function sernum()
{
    $template   = 'XX99-XX99-99XX-99XX-XXXX-99XX';
    $k = strlen($template);
    $sernum = '';
    for ($i=0; $i<$k; $i++)
    {
        switch($template[$i])
        {
            case 'X': $sernum .= chr(rand(65,90)); break;
            case '9': $sernum .= rand(0,9); break;
            case '-': $sernum .= '-';  break; 
        }
    }
    return $sernum;
}


// try it, lets generate 4 serial numbers
echo '<pre>';

for ($i=0; $i < 4; $i++) echo sernum(), '<br/>';

echo '</pre>';
?>

Output:

WS41-IZ91-55XO-23WA-WVZS-20VK

SJ42-CV50-79DA-55UV-TERR-28IJ

LY80-CN84-69LV-73EW-ZZEU-09AI

IS86-RG15-39CG-38HK-XLUG-86FO

Then check to see if the generated key is in use (1/1,000,000 chance~)

Upvotes: 4

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