Comment by cesarb

> Without security, the system simply cannot be trusted to do anything correctly, not even add 1 and 1 together.

Not really. For a simple example, imagine a calculator software which has been mathematically proven to work correctly for any number with 30 or less digits, but which overflows a fixed-size buffer if the user inputs a number with more than 30 digits. That software could absolutely be trusted to add 1 and 1 together, while still having a security issue.