When your website's audience visits your site, their browser checks for and views your SSL Certificate. Your visitors' computer confirms your site's identity through your SSL's Certificate Authority, the organization that issed the digital certificate.
If everything checks out OK, your visitors' computer and the server your website is hosted on perform a digital "handshake". This is when the computer and your server determine what sort of encryption will be used to create a secure connection. This is known as the Secure Socket Layer, or SSL. The flow of data between the computers is encrypted, meaning it is jumbled up into a code to prevent unauthorized viewing. Your visitors' browser will display some sort of identifer, usually a padlock, indicating to your visitor that a secure connection with your website has been made.
SSL Certificates are granted from a Certificate Authority (CA). The Certificate Authority's job is to verify that the website owner is in fact who they say they are. A business verification may also occur if the site is owned by a business, most likely an eCommerce store. A copy of the SSL Certificate is received once the CA verifies the site owner. The web site owner is then free to install their SSL Certificate on their server for their website.
Once the web server that is hosting your site is accessed by your visitor's browser, an "SSL handshake" takes place. This means the browser and the server have established a key informing each other that it's safe to communicate and the SSL Certificate is in fact valid. Most importantly, your visitors will also know that any information they are transmitting to you, whether it be a password, credit card or social security number, is secure due to your use of the SSL Certificate.
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