The HTTP or also called Transfer protocol of hypertext is what it delimits the techniques and norms of the transport of data from the servers where a site lodges until our equipment from where we are seeing it, by all means that all this happens without we notice it and while we can see and to review the site which we have written in the navigator everything would have to go well.
The problem with this protocol arises due to its vulnerability, because it allows that others can see the actions that we generated in each site, and although this is not serious in certain webpages, there is a great difference in which they know my search in Google to that they know the key which I am introducing to pay a product online.
In cases as interchange of e-mails, income of keys of security, transactions in line, among others, it is important to maintain the privacy and to assure the protection our data and for them is used the HTTPS or HTTP on a certificate SSL, this allows to transmit based data, reason why if somebody tried to obtain our entered information would not be possible to decipher it to him. The message is only deciphered completely when arriving at the designated location
Something very important that you must consider when you install SSL, is that your site will require more power in the data transmission, since will require of an additional processing when having to base and to decipher data, for it considers hosting of confidence that assures the lodging to you in servers quality and a good support in case you require it.