Hi m16191,
I am not sure I understand your problem correctly.
We have 3 protocols, NX , SSH and HTTP.
Please note that SSH is not related to TLS, these are separated standards.
The NX protocol is implemented using TLS/SSL standard and OpenSSL and it uses exactly TLS 1.2. TLS is a specification of SSL. HTTP, the third protocol, uses SSL as well which includes TLS 1.2 (and others).
You can also check this article: https://www.nomachine.com/AR12K00768. Further reading about encryption is also available here: https://www.nomachine.com/AR10K00705