Kerckhoffs' cryptography principle (also called Kerckhoffs' desideratum, assumption, axiom, doctrine, or law) was stated by Dutch cryptographer Auguste Kerckhoffs in the 19th century. The principle states that a cryptosystem must be secure even if everything about the system, except the key, is public knowledge. This concept is widely adopted by cryptographers, in contrast to security through obscurity, which is not."

Most hardware wallets violate this principle.