Welcome! Cryptography I hear you say!
Well, if you are interested, along with what nostr:npub1m3xdppkd0njmrqe2ma8a6ys39zvgp5k8u22mev8xsnqp4nh80srqhqa5sf shared, GitCitadel does a few things now, including a library I maintain as the C reference implementation of the nip44 encryption spec. The library is called noscrypt, and it's purpose is to be a fully featured (and compliant) cryptography utility library, it focuses on correctness, stability, and performance.
We also work on Aedile, an up-and-coming C++ sdk.
Here is the full project list