Putting PGP keys in EFS Storage


I have a automated workflow that takes data and outputs several files from this data (PDF etc) and I’m looking to use GNUPG encrypting data as part of PCIDSS accreditation and I was wondering how the keys are stored within the system as the rules around PGP keys and PCI-DSS are that the key’s must be encrypted with another form of encryption that is at least to the same level on encryption as they key.

So really just wanting to understand how the keys are stored as it has been suggested to me to store the keys in a folder that is controlled by EFS that only the local system account can access as that’s what will be doing the encryption.

Any help would be greatly appreciated