Simple data protect in php. Javascript version here: https://github.com/dangdungcntt/data-protect

DataProtect.php

<?php

class DataProtect
{
    protected static function substrAndToInt($string, $index = 0, $length = 3)
    {
        return hexdec(self::unmix(substr($string, $index, $length)));
    }

    protected static function pad($string, $length = 6, $char = '0')
    {
        return (strlen($string) < $length ? str_repeat($char, $length - strlen($string)) . $string : $string);
    }

    protected static function mix($string)
    {
        $firstSeg = floor(strlen($string) / 2);

        return self::pad(rand(1, 99) . '', 2)
            . substr($string, 0, $firstSeg)
            . self::pad(rand(1, 99) . '', 2)
            . substr($string, $firstSeg, strlen($string) - $firstSeg)
            . self::pad(rand(1, 99) . '', 2);
    }

    protected static function unmix($string)
    {
        $originalLength = strlen($string) - 6;
        $firstSeg = floor($originalLength / 2);

        return substr($string, 2, $firstSeg) . substr($string, $firstSeg + 4, $originalLength - $firstSeg);
    }

    /**
     * @param $input
     * @param $secret
     * @param int $seg
     * @return string
     * @throws \Exception
     */
    public static function encrypt($input, $secret, $seg = 3)
    {
        if (!in_array($seg, range(2, 15))) {
            throw new \Exception('Invalid seg. seg must between 2-15');
        }

        if (!$input) {
            throw new \Exception('Invalid input. Input must not empty');
        }

        if (!$secret) {
            throw new \Exception('Invalid secret. Secret must not empty');
        }

        $decSeg = hexdec(str_repeat('f', $seg));

        $time = round($decSeg * rand(0, 1000) / 1000);

        $key = 10;

        foreach (str_split($secret) as $cur) {
            $key = ($key * 10 % $decSeg) + (ord($cur) % $decSeg);
            $key %= $decSeg;
        }

        $base = $key ^ $time;

        $time16 = dechex($time);

        $output = self::mix(self::pad($time16, $seg));

        foreach (str_split(trim($input)) as $c) {
            $output .= '' . self::mix(self::pad(dechex(ord($c) ^ $base), $seg));
        }

        return $output;
    }

    /**
     * @param $encrypted
     * @param $secret
     * @param int $seg
     * @return string
     * @throws \Exception
     */
    public static function decrypt($encrypted, $secret, $seg = 3)
    {
        if (!in_array($seg, range(2, 15))) {
            throw new \Exception('Invalid seg. seg must between 2-15');
        }

        if (!$encrypted) {
            throw new \Exception('Invalid encrypted. Encrypted must not empty');
        }

        if (!$secret) {
            throw new \Exception('Invalid secret. Secret must not empty');
        }

        $decSeg = hexdec(str_repeat('f', $seg));

        $seg += 6;

        $key = 10;

        foreach (str_split($secret) as $cur) {
            $key = ($key * 10 % $decSeg) + (ord($cur) % $decSeg);
            $key %= $decSeg;
        }

        $time = self::substrAndToInt($encrypted, 0, $seg);

        $base = $key ^ $time;

        $result = '';

        $encryptedLength = strlen($encrypted);

        for ($i = $seg; $i < $encryptedLength; $i += $seg) {
            $result .= chr(self::substrAndToInt($encrypted, $i, $seg) ^ $base);
        }

        return $result;
    }
}