Suppose I have a secure channel between client and server, with proper certificate validation etc (actually, ssh session).
I want to establish a secure connection between my own application on a server and client, but don't want to implement TLS, or some sort of certificate validation, or send my data through SSH tunnel.
Is it enough to generate a strong random key, send it through ssh session, and simply use that key for symmetric encryption, say, AES?
Edit. Realized my question was not clear enough. Real question should look like so:
If I have a pre-shared one-time key, is it worth to use TLS? What problems can I encounter with my own implementation using strong symmetric encryption, like AES?