Final, final, final, final conclusion: due to the complexity of computers, the only reliable way to achieve a moderate security in a system is to prevent it from being powered on.
The concept of C-I-A addresses this. Confidentiality, Integrity, Availability. If a system is not available for use then all the confidentiality of communications and integrity of data is useless.
"Pioneered method of keeping restrooms clean by keeping them locked during business hours."