I'm trying to get my head around 3.6.3 and 3.6.2 in the PCI-DSS standard, secure cryptographic key storage and distribution.
Would having two 256 bit key halves stored in separate, isolated locations which are XORed together to create the data encrypting key count? Is a key encrypting key strictly required?
The encryption service would be able to read both halves and assemble the data encrypting key. All administrative access to a given key half will be restricted by RBAC and auditing. Assuming that the keys are from a suitability random data source having one of the key halves wouldn't provide a bit (yes, pun intended) of information as to the actual content of the key.