Encrypt and decrypt a license key in PHP

Question

I need to generate a license key with a given name, product title and an expiry date. If one of my customers buys my product and uses it, he has to enter this license key.

I tried so much methods and I have no clue how to achieve this in PHP. The key should be safe for reproduction. What would be the best way to create a license key encryption and decryption in PHP?

Answer 1

The below code may help you:

function encrypt($sData, $secretKey){
    $sResult = '';
    for($i=0;$i<strlen($sData);$i++){
        $sChar    = substr($sData, $i, 1);
        $sKeyChar = substr($secretKey, ($i % strlen($secretKey)) - 1, 1);
        $sChar    = chr(ord($sChar) + ord($sKeyChar));
        $sResult .= $sChar;

    }
    return encode_base64($sResult);
} 

function decrypt($sData, $secretKey){
    $sResult = '';
    $sData   = decode_base64($sData);
    for($i=0;$i<strlen($sData);$i++){
        $sChar    = substr($sData, $i, 1);
        $sKeyChar = substr($secretKey, ($i % strlen($secretKey)) - 1, 1);
        $sChar    = chr(ord($sChar) - ord($sKeyChar));
        $sResult .= $sChar;
    }
    return $sResult;
}

function encode_base64($sData){
    $sBase64 = base64_encode($sData);
    return str_replace('=', '', strtr($sBase64, '+/', '-_'));
}

function decode_base64($sData){
    $sBase64 = strtr($sData, '-_', '+/');
    return base64_decode($sBase64.'==');
}

Here

$secretKey; // Your secret key can be anything which you only know it. So no one easily decrypt through any tool. (recommended often change the $secretKey).

Answer 2

well there is NuCoder which can provide such type of functionality

Answer 3

try next service www.e-ll.ro | Encrypt with License Key Any PHP Code/Source/Script/Website

Answer 4

For local license go for ionCube or php's openssl as mcrypt is abandonned. For remote license go for php's curl. It probably gives you some idea how to do so http://www.phplicengine.com I also suggest to take a look at phpseclib in github or packagist. It uses first openssl, if not available then switches to mcrypt. With openssl or mcrypt you can encrypt and decrypt. As about method I suggest AES_128.