3ds-crypto-server
ARM11 Userland homebrew for 3ds crypto over the network. Requires my crypto-patches branch of Luma3DS.
Also requires very recent ctrulib (for PS_EncryptDecryptAES to actually work).
Probably also requires you to enable "Patch SVC/service access" in Luma config. Gets about ~925 KB/s on my console/network. See crypto_client.py for an example client.