There are several requirements for SSL.
Replication Server 15.0 or later supports TLS version 1.0 or 2.0; it does not support SSL version 3.0.
SSL requires Replication Server version 12.5 and later. Earlier versions of Replication Server do not support SSL.
The Replication Server Administrator must generate and secure the server certificates and trusted root CA certificates as files outside Replication Server.