Can't a malicious entity running this system identify decoy messages by the fact that they are conveniently published at intervals divisible by 5 minutes? ie. 17:07:43 then 18:42:44
But remember that we rely on the lambda scheduler to run it
That does boy have perfect accuracy, so that helps too
Finally, you aren't publishing every 5 minutes, you execute it once a minute, and have 25% chance to publish, so it's going to be mixed