Why is it necessary to have a certification signed by the third party?


Self-signed certificates can be created by anyone and in it is enough sometimes.
In this case we have to make sure that we connect to the server using the right certificate every time. This is complicated, therefore only recommended for personal use.

However, if we are planning to protect a publicly available service with SSL, we need to have our certificate signed by a trusted third party. This will not only make the users’ work easier but also gains trust and truly secures the connection.
The certifying party makes sure that the person or organisation requesting the signature are really who they claim to be, so the users can trust the signed certificate.

When using an EV certification, the requester is subject to the strictest checks, so phising attacks can be avoided. When accessing a website that uses EV certification, modern browsers will display a green address bar and will show the domain owner’s name.