All USB sticks are not created equal

"What if someone overwrites the key while verifiying it?" Jules asked.

"Your creativity scares me sometimes" Shuri said, "but that seems doable indeed."

"We could avoid the issue with a USB stick with a hardware readonly switch" Leiko started, "When we verify the USB stick, we switch it to readonly, and we switch it back to read/write when booting on it."

"Good idea" Adira said, "but then we should boot on the same computer that verified the key."

"Why so?" Jules asked.

"Because otherwise someone could replace the USB stick between the verification and the boot. You know, a sleight of hand trick..." Adira replied.

"True." Jules said, "but then we don't need an always offline computer, we could use any computer. We can configure the NixOS on the USB stick to disable all network interface so that we are sure it remains offline."

"Indeed." Adira remarked, "and that will simplify things at the same time."

"What if someone makes a corrupted key and volonteer to verify it." Jules started, "They could fake the verification couldn't they?"

"That's a good point" Adira replied, "Then the person and the computer that creates the key and the one that verifies it should be different."

"And to make prepared attacks even harder, we could pick the computer we use at random." Shuri said.

"That looks like great ideas to me!" Jules said, "Let's add all that to our process".

Five years later, Leiko comes to Jules house.

"I had no choice Jules, I am sorry." she said.

"Sorry about what?" Jules asked.

"I stole the root CA for Evil Corp." Leiko started, "They came to my home a year ago and told me to steal it or face the consequences. I concealed cameras in my glasses and stole the shares."

"You can stop there Leiko" Jules interrupted, "I understand. You have nothing to be sorry about, you did what you had to do. Now, the important thing is to take care of you."

Leiko wanted to continue to talk though, and Jules listened. She felt relieved to finally express the rage, fear and sadness she had been keeping for herself for a year.

Late that night, Jules went back in time. Protecting his friends from harm will always be a good reason to tickle the spacetime continuum.

Jules started to think that the challenge to keep the root CA really secure was much more tricky that what one believes intuitively.