Secure Proxy Servers do not exist, first of all there is no encryption between them, no authentication and 99.99% of all proxies are hacked proxies being used to harvest your data and passwords. You should know that no proxy server is secure or anonymous, in fact they are quite the opposite and unfortunately many people have fallen victim to such proxy servers.
Instead of looking for a secure proxy server, you should get a good VPN acount, because they offer true security, reliability and speed and are simply far superior compared to any Proxy Server.
To answer the question again, there is no such thing as a secure proxy server, there are proxy servers, but they are insecure, slow and unreliable.
proxy, servers, encryption, authentication, proxies, hacked, harvest, passwords, server, vpn, acount, reliability, insecure, unreliable,