Differentiate between HTTP, HTTPS, SSL and SSH using a client server application as example.

HTTP, HTTPS, SSL, and SSH are all protocols used for communication in networks. They are used in client-server applications to ensure the smooth transfer of data. Here's how they differ:

1. HTTP (Hypertext Transfer Protocol): This is an application protocol used for data communication in the World Wide Web. It uses a client-server model where an HTTP client opens a connection and sends a message to an HTTP server. The server then responds with a status line, including the message's protocol version and a success or error code, followed by a MIME-like message containing server information, entity meta-information, and possible body content. An example of this is when you enter a URL in your web browser (the client), the browser sends an HTTP request to the server where the website is hosted.

2. HTTPS (Hypertext Transfer Protocol Secure): This is simply the secure version of HTTP. It's the protocol over which data is sent between your browser and the website that you're connected to. The 'S' at the end of HTTPS stands for 'Secure'. It means all communications between your browser and the website are encrypted. HTTPS is often used to protect highly confidential online transactions like online banking and online shopping order forms.

3. SSL (Secure Sockets Layer): This is a standard security technology for establishing an encrypted link between a server and a client. It ensures that all data passed between the web server and browsers remain private and integral. SSL is an industry standard and is used by millions of websites in the protection of their online transactions with their customers.

4. SSH (Secure Shell): This is a cryptographic network protocol for operating network services securely over an unsecured network. Typical applications include remote command-line, login, and remote command execution, but any network service can be secured with SSH. SSH provides a secure channel over an unsecured network in a client-server architecture, connecting an SSH client application with an SSH server.

In summary, HTTP and HTTPS are used for transferring web pages from server to client, with HTTPS having an added layer of security. SSL is used to encrypt the connection between client and server, and SSH is used for securely executing network services and transferring files.