Also note that neither EncryptData nor DecryptData have any way of passing a key in their API. So it's very unlikely that these implementations could be conditionally compiled in place of a real implementation (but they're the only definition of these functions in the repository anyway).
I assume this has been ported from Windows and later never implemented the ripped out components. That said, I don't know the windows API so apart from confirming that they exist in Windows docs[2] I can't assess how valid their usage was.
[1] - https://github.com/microsoft/omi/commit/edbe231042173018c529...
[2] - https://docs.microsoft.com/en-us/windows/win32/api/dpapi/nf-...
There could have been other smells involved, like the key being held in some more global scope instead of being passed in via the call stack.