An electronic system 100 for generating a cryptographic key, the system comprising a memory 110 used as a physically unclonable function, the memory being writable, volatile and configured such that upon each powering-up of the memory the memory settles into a memory content which depends upon at least partially random physical characteristics of the memory, the memory being accessible through a memory interface, and a key derivation unit 150 configured to derive the cryptographic key from the memory content into which the memory settled, wherein the electronic system for generating a cryptographic key further comprises, a memory read-out unit connected to the memory through the memory interface and to the key derivation unit, the memory read-out unit comprising an address scrambler 140 for retrieving the memory content over the memory interface in a scrambled order.