“Now… you asked me to construct some more ciphers for you. I am sorry, my lord, but I must have misunderstood your requirements. What was wrong with the first ones I did?”
Vetinari sighed. “I am afraid they were unbreakable, Leonard.”
“It is hard to explain,” said Vetinari, aware that what to him were the lucid waters of politics was so much mud to Leonard. “These new ones you have are… merely devilishly difficult?”
“You specified fiendishly, sir,” said Leonard, looking worried.
“There does not appear to be a common standard for fiends, my lord, but I did some research in the more accessible occult texts and I believe these ciphers will be considered ‘difficult’ by more than ninety-six percent of fiends.”
“They may perhaps verge on the diabolically difficult in places–”
“That is not a problem. I shall use them forthwith.”
Leonard still seemed to have something on his mind.
“It would be so easy to make them archdemonically diff–”
“But these will suffice, Leonard,” said Vetinari.
“My lord,” Leonard, almost wailed, “I really cannot guarantee that sufficiently clever people will be unable to read your messages!”
“But, my lord, they will know what you are thinking!”
Vetinari patted him on the shoulder.
“No, Leonard. They will merely know what is in my messages.”
– politics | Terry Pratchett, The Fifth Elephant