Online PHP editor | output for BXk3d

<?php $uuid = sprintf('%04x%04x%04x%04x%04x%04x%04x%04x', // 32 bits for "time_low" mt_rand(0, 0xffff), mt_rand(0, 0xffff), // 16 bits for "time_mid" mt_rand(0, 0xffff), // 16 bits for "time_hi_and_version", // four most significant bits holds version number 4 mt_rand(0, 0x0fff) | 0x4000, // 16 bits, 8 bits for "clk_seq_hi_res", // 8 bits for "clk_seq_low", // two most significant bits holds zero and one // for variant DCE1.1 mt_rand(0, 0x3fff) | 0x8000, // 48 bits for "node" mt_rand(0, 0xffff), mt_rand(0, 0xffff), mt_rand(0, 0xffff) ); $uuid = 0; $packedUuid = pack('H*', $uuid); $unpackedUuid = unpack('H*', $packedUuid)[1]; $unpackedUuid = $unpackedUuid[1]; echo $uuid . PHP_EOL; echo strlen($uuid) . PHP_EOL; echo $packedUuid . PHP_EOL; echo strlen($packedUuid) . PHP_EOL; echo $unpackedUuid . PHP_EOL; echo strlen($unpackedUuid) . PHP_EOL;