Hypertext Transfer Protocol (HTTP in further text) is a protocol that enables the transfer of information on the Web. Precisely, the main purpose of this protocol is to enable the publication and presentation of HTML (HyperText Markup Language – language used to create web pages) documents, that is web sites.
HTTPS = HTTP + security
On the other hand, HTTP Secure (HTTPS) enables secure data communication for the World Wide Web pages by using SSL/TLS (Secure Sockets Layer/Transport Layer Security) protocol. SSL and TLS encrypt the data traveling between your browser and the Web server that stores the content of web pages you are accessing. Web pages that are protected by SSL/TLS protocol have https:// as a starting expression in the URL link, while those that use HTTP protocol have http:// as a starting expression.
HTTPS is often used for financial transactions on the World Wide Web (you can observe this by paying bills online) and other sensitive transactions in corporate information systems.
Why should you trust HTTPS
The whole idea of SSL/TLS relies on so called trusted “organizations/authorities” that can issue trust certificates for sites and servers, which then make them secured and trustworthy. A list of this “trusted organizations” comes pre-installed in your computer, so your web browser automatically trusts the certificates coming from these “authorities”, and then the sites that are signed by them can be trusted as well. This signature then means that the site’s owner is checked and the site can be trusted (and therefore the more secure protocol, i.e. HTTPS, can be used to access it).
Based on being said above, we can conclude that accessing pages with HTTPS in the web address (URL) is more secure than accessing those that use HTTP.
HTTPS is indeed a secure version of HTTP, but only if you follow certain rules. For example, in case you came across an alert of any kind, you should not ignore it and continue with surfing the Web. There is certainly some reason why this alert appeared and you should understand it, and eventually properly react for the sake of your security.