What is a Secure Sockets Layer (SSL)?
The secure Sockets Layer (SSL) is an internet security protocol that establishes an encrypted connection between a web server and a browser.
Sites using Secure Sockets Layer technology begin with https：// rather than the http：// used by unsecured sites. The sites will also display a lock icon and comment confirming the site is secure when you view the site’s information, as shown below.
Secure Sockets Layer helps to keep data transmitted between a server and browser private. This protects sensitive information such as login credentials, credit card details, and other personal data from being intercepted or tampered with by criminals, hackers, and other unauthorized parties.
Importance of Secure Sockets Layer
The Secure Sockets Layer is crucial for securing data sent over the web. Without a Secure Socket Layer, anyone can view any data exchanged over the internet.
For example, imagine a visitor visits an ecommerce store, adds an item to their cart, and then proceeds to checkout to complete the purchase. If the site does not have a Secure Sockets Layer, their card details will be visible to any hacker who may have intercepted their communication.
Their card details will also be visible to anyone who has access to the ecommerce site’s backend long after they have completed the purchase.
The Secure Sockets Layer prevents third parties from accessing the data during and after the transaction. Anyone who manages to intercept the communication or access the data after the transaction will only encounter garbled information they cannot decode.
A Secure Sockets Layer can also prevent certain cyber attacks from being launched against a server. This is because it authenticates websites when trying to establish a secure connection. This works against scammers who create fake sites to steal user data. Such sites will fail authentication and will be exposed as fake.
Secure Sockets Layer (SSL) vs Transport Layer Security (TLS)
The Secure Sockets Layer and Transport Layer Security are used to secure the communication between a browser and a server. Both usually cause sites to begin with the more secure https rather than the unsecured http.
However, the Secure Sockets Layer has been deprecated and has not been updated since 1996. It was replaced by the Transport Layer Security in 1999. However, many still use the term ‘Secure Sockets Layer’ when referring to Transport Layer Security.
Transport Layer Security is the direct successor of the Secure Sockets Layer. The name change only occurred when the Internet Engineering Task Force (IETF) released an update for the Secure Sockets Layer in 1999. Netscape had developed the original Secure Sockets Layer. However, it was no longer involved in the development, so the name change signaled a change in the developer.
What is an SSL Certificate?
An SSL certificate is a digital certificate used to authenticate and create a secure and encrypted connection with a website. The SSL certificate is actually a TLS certificate since SSL is now redundant. However, it is often called the SSL certificate.
The SSL certificate ensures that the visitor and server are who they say they are. This ensures that no third-party person or system can intercept their communications. It also ensures that their communication and any information shared remain encrypted even after the communication has been terminated.
The presence of the SSL certificate is the reason sites change from http to https. Without the certificate, the site would still retain the unsecured http. SSL certificates are issued by third-party organizations called certificate authorities (CA).
Types of SSL Certificates
There are three types of SSL certificates, depending on the domains for which they can be used. They are:
- Single-domain
- Wildcard
- Multi-domain
1 Single-Domain
A single-domain SSL certificate is issued to a single domain. For instance, if issued to a domain like example.com, it can only be used on that domain. It cannot be used on other sites or even subdomains under the domain. So, it will not work with subdomains like blog.example.com and shop.example.com.
2 Wildcard
A wildcard SSL certificate is issued to a domain and its subdomains. For instance, a wildcard SSL certificate issued to example.com will also cover subdomains like blog.example.com and shop.example.com.
3 Multi-Domain
A multi-domain SSL certificate is issued to multiple domains that are not necessarily related to one another. So, two unrelated websites like example.com and rankmath.com, can share the same multi-domain SSL certificate.
Types of SSL Certificate Validation
SSL certificates have different levels of validation. Starting from the least stringent to the most stringent, they are:
- Domain validation
- Organization validation
- Extended validation
1 Domain Validation
A domain SSL certificate is the least stringest and cheapest of all SSL certificates. It is also the easiest to receive from a certificate authority. The site receiving the SSL certificate only needs to prove that it owns the domain name. After that, they will be issued the SSL certificate.
2 Organization Validation
The organization SSL certificate is more stringent and expensive than the domain SSL certificate but is less stringent than the extended SSL certificate. The certificate authority will contact the site requesting the SSL certificate and request specific information before issuing the SSL certificate.
3 Extended Validation
The extended SSL certificate is the most stringest and expensive of all SSL certificates. The certificate authority will contact the site requesting the SSL certificate to request specific information. The certificate authority will also run a background check on the organization before issuing the certificate.