Setting up TLS is highly recommended. The key exchange between the KeyTrustee server and the Nav Encrypt client is encrypted with PGP on the wire; but, should still be encapsulated with TLS. See this doc.
The AES-NI based encrypt/decrypt based should all be done in the HW and have minimal performance impact.
You want to make sure that:
- HW has AES enabled, this is the default these days
- You have plenty of entropy available in the kernel. See this doc.
NavEncrypt is not managed by CM.