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MbamGen.php

<?php

class MbamGen {
	public function get_key() {
		$data = [
			'id' => $this->random_char() . $this->random_char() . $this->random_char() . $this->random_char() . $this->random_char(),
			'key' => ''
		];
		$hash = strtoupper(md5($data['id']));

		for ($i = 0; $i < 32; $i += 2) { 
			$nextDigit = hexdec(substr($hash, $i, 2)) & 31;
			$withDash = ((($i % 8) == 0) && ($i > 0));

			$data['key'] .= ($withDash ? '-' : '');
			$data['key'] .= substr($this->get_chars(), $nextDigit, 1);
		}

		return $data;
	}

	private function random_char() {
		return $this->get_chars()[mt_rand(10, strlen($this->get_chars()) - 1)];
	}

	private function get_chars() {
		return '0123456789ABCDEFGHJKLMNPQRTUVWXY';
	}
}