Before she addresses an audience, Rachel Noble, Australia’s cyber spy chief, does a mental computation to make sure she doesn’t blurt out a state secret.

“It is mentally challenging because I’ve got nearly 30 years of classified things in my head,” says Noble, the director-general of the Australian Signals Directorate. “When you are speaking publicly, you are constantly sifting through those memories and thinking, ‘How do I know that? Is that a secret? What can I talk about publicly about what I know?’”