Final answer:
The Registry and hibernation files are two files that may contain encryption keys normally stored only in memory on a Windows system.
Step-by-step explanation:
The two files that may contain encryption keys normally stored only in memory on a Windows system are the Registry and hibernation files. The Registry is a central database on Windows systems that stores configuration settings and other important information. It can also contain encryption keys used for various purposes.
Hibernation files, on the other hand, are created when a system enters hibernation mode. These files contain the entire contents of the system's RAM, including any encryption keys that may have been in memory at the time of hibernation.