Data packages sent between server nodes and monitor clients are end-to-end encrypted with the node certificate.
The encryption used for this is AES/HCM/PKCS5Padding (256bit keys).
This is possible to verify if you click on Help->Debug->Connection info
For encryption and signing messages, certificates using SHA256withECDSA, is used, and regenerated every 10 minutes.
Details are available if you click on Help->Debug->Certificates
The negotiation of encryption uses Elliptic-curve Diffie-Hellman key agreement.