What is Private cloud and what exactly make it private?

[sdiri]

I am learning cloud computing but i am still confused in some basics. While it is accessible from the internet, what exactly makes a Virtual Private Cloud (VPC) private? Is it the VPN connection, the solution architecture, or the virtual network?

Is it necessary for it to be an on-prem solution boosted with some cloud services to be considered a VPC?

What's the difference between an application that allows some clients to access it over the internet using cURL or a browser's HTTP/HTTPS protocol in a public cloud and an application in a private cloud?

Suppose a web application is hosted in a public cloud, but it uses a private network to establish network connections between some services, such as invoking some analytical jobs. Is that part considered a private cloud?

If so, what if a third party wants to use the analytics results of my application? Is it still considered a private cloud?

I have a basic understanding of the cloud and have done some labs with scaling options, private network firewalls, and load balancers. However, the distinction between private and public clouds remains unclear to me. Could you please clarify?

[sdiri]

Any one can help to improve or rectify this please ? 

A Virtual Private Cloud (VPC) is considered private because it provides a secure, isolated network environment within a public cloud infrastructure. The main factors that make a VPC private include:

1. Network Isolation: A VPC is isolated from the public internet, and can only be accessed by authorized users via a VPN connection, a secure connection to a private network, or through a Virtual Private Network (VPN) gateway.

2. Access Control: Access to resources within a VPC is tightly controlled through firewall rules, security groups, and network access control lists (ACLs). This allows administrators to restrict access to the VPC and its resources based on specific security requirements.

3. Encryption: Data transmitted within a VPC can be encrypted using industry-standard encryption protocols, making it more secure and less susceptible to unauthorized access.

4. Dedicated Resources: A VPC provides dedicated resources, such as compute, storage, and network, which are isolated from other customers' resources and less susceptible to interference from other workloads.

To summarize, the combination of network isolation, access control, encryption, and dedicated resources makes a VPC private and secure.