Non-cryptographer here, but I think homomorphic encryption is fascinating. IIRC, it allows a user to perform operations on encrypted data, without being able to decrypt the original data. I see it as the holy grail of data anonymization and I understand it to be cutting edge stuff.
I mainly thought it was neat there's a way to do matching on encrypted data without deterministic encryption. It's based on this example - https://github.com/homenc/HElib/tree/master/examples/BGV_cou... - which explains more about how it works and why it's O(N).
Couldn't you just use a file with (normally) encrypted keys and values? I'm probably slightly misunderstanding the premise of this project.