source/Core/UniversallyUniqueIdGenerator.php
protected function _generateBasedOnMtRand()
    {
        return sprintf(
            '%04x%04x-%04x-%04x-%04x-%04x%04x%04x',
            mt_rand(0, 0xffff),
            mt_rand(0, 0xffff),
            mt_rand(0, 0xffff),
            mt_rand(0, 0x0fff) | 0x4000,
            mt_rand(0, 0x3fff) | 0x8000,
            mt_rand(0, 0xffff),
            mt_rand(0, 0xffff),
            mt_rand(0, 0xffff)
        );
    }
protected function _generateBasedOnMtRand()
    {
        return sprintf(
            '%04x%04x-%04x-%04x-%04x-%04x%04x%04x',
            mt_rand(0, 0xffff),
            mt_rand(0, 0xffff),
            mt_rand(0, 0xffff),
            mt_rand(0, 0x0fff) | 0x4000,
            mt_rand(0, 0x3fff) | 0x8000,
            mt_rand(0, 0xffff),
            mt_rand(0, 0xffff),
            mt_rand(0, 0xffff)
        );
    }
protected function _generateBasedOnMtRand ( ) { return sprintf ( '%04x%04x-%04x-%04x-%04x-%04x%04x%04x' , mt_rand ( 0 , 0xffff ) , mt_rand ( 0 , 0xffff ) , mt_rand ( 0 , 0xffff ) , mt_rand ( 0 , 0x0fff ) | 0x4000 , mt_rand ( 0 , 0x3fff ) | 0x8000 , mt_rand ( 0 , 0xffff ) , mt_rand ( 0 , 0xffff ) , mt_rand ( 0 , 0xffff ) ) ; }
Generates UUID based on mt_rand.

@return string
Generates UUID based on mt_rand .