Are you storing those keys in the TPM or a smartcard? Is the machine connected to the Internet, or even to the local network? In other words ask yourself if the

Are you storing those keys in the TPM or a smartcard? Is the machine connected to the Internet, or even to the local network? In other words ask yourself if the keys would be compromised by anyone getting root on the machine, and then: * if yes, what are the ways that one could get root on that machine? Is it better or worse on the MBP? * if not, are the keys stored in a place which is related to the secure processor? And also: is there a reason why somebody could 1) know that you have keys on that machine 2) be interested in those keys 3) have the resources to conduct the attack? In a nutshell, analyze your attack surface and model your threats.