Most syslog implementations including rSyslog and syslog-ng have the option to encrypt logging data over the wire through the use of TCP Syslog + TLS.
It would be great if I could setup an rSyslog relay to send data to logstash over a TLS encrypted connection.
the 'tcp' input supports tls now, and we could add tls support to the tcp output.
Anyway, specific to this request, 'syslog' input is going away, 'syslog' output might be as well. So I'm marking this 'wont fix'