This is effectively ...
... Kerckhoff's principle: the security of a cryptosystem must be in key choice alone; knowing everything about a [good] cryptosystem should not help you crack it in the absence of at least partial knowledge of the key.
... Kerckhoff's principle: the security of a cryptosystem must be in key choice alone; knowing everything about a [good] cryptosystem should not help you crack it in the absence of at least partial knowledge of the key.