CentralNotice From Wikipedia, the free encyclopedia Jump to: navigation , search Not to be confused with Kirchhoff's laws (disambiguation) . In cryptography , Kerckhoffs' principle (also called Kerckhoffs' desideratum , Kerckhoffs' assumption , axiom , doctrine or law ) was stated by Dutch cryptographer Auguste Kerckhoffs in the 19th century: A cryptosystem should be secure even if everything about the system, except the key , is public knowledge. Kerckhoffs' principle was reformulated (or perhaps independently formulated) by American mathematician Claude Shannon as "the enemy knows the system", [1] i.e., "one ought to design systems under the assumption that the enemy will immediately gain full familiarity with them". In that form, it is called Shannon's maxim . In contrast to " security through obscurity ", it is widely embraced by cryptographers. 1 Origins 2 ...