how can create checksum

[MmdRasoul]

hi i used this code for make checksum for create a room.
[http://test-install.blindsidenetworks.com/bigbluebutton/api/create?....]
my checksum code is not true! ?i get error.

<?php $sec="8cd8ef52e8e101574e400365b55e11a6"; $parameters = [ 'meetingID' => 'Test', ]; $queryBuild = http_build_query($parameters); $checksum = sha1('create' . $queryBuild . $sec); echo $checksum; ?>