I want to do generate individual AES keys for a number of smart cards, based on a random master key (key diversification) and the serial number of the card.
According to the answers to this question HKDF is the/one way to go.
HKDF has three inputs, ikm
, salt
and info
. Feeding in the serial number as part of ikm
seems to be incorrect usage (and maybe dangerous because it makes the IKM less random?). That leaves salt
and info
, which one should I use?
salt
because differentinfo
might not lead to different output keys, is that what you mean? $\endgroup$