Have you heard of the NSA wiretapping of all calls and in addition to, monitoring of all internet communications with an algorithm that picks up key words that can evidence internal, non state threats?
They have a facility in Nevada just for the purpose, and so with prayer, they can never eavesdrop or pickup as it is a supernatural communications channel between you and God.
It is both secure and unbreakable as the only ones will hear are the demons but the Lord will not let them reveal it. Just don’t pray aloud if you don’t want them to know what you’re praying about ;)