What is an SSL Certificate?
An SSL certificate is a digital certificate that authenticates a website's identity and enables an encrypted connection. SSL stands for Secure Sockets Layer, a security protocol that creates encrypted links between a web server and a web browser.
Companies and organizations should add an SSL certificate to their websites to secure online transactions and protect the confidentiality and safety of customer information.
In short: SSL ensures internet connections are secure and prevents criminals from reading or modifying information transferred between two systems. If you see a padlock icon next to the URL in the address bar, it means the site you're visiting is protected by an SSL certificate.
Since its introduction 25 years ago, the SSL protocol has had many versions, all of which eventually encountered security issues. Later, a renewed version under a new name called TLS (Transport Layer Security) was introduced, which is still used today. However, the term "SSL" was not abandoned, and the new protocol version is still commonly referred to by its old name.
How Do SSL Certificates Work?
SSL ensures that the data transferred between users and websites or between two systems remains unreadable. It uses encryption algorithms to scramble data during transmission, preventing hackers from reading it. This data can include sensitive information such as names, addresses, credit card numbers, or other financial details.
The process works as follows:
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A browser or server attempts to connect to a website secured with SSL (i.e., a web server).
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The browser or server requests the web server to identify itself.
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The web server responds by sending a copy of its SSL certificate.
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The browser or server checks whether it trusts the SSL certificate. If it does, it sends a signal back to the server.
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The web server then sends back a digitally signed acknowledgment to start an encrypted session.
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Encrypted data is shared between the browser/server and the web server.
This process is sometimes referred to as the "SSL handshake." Though it may seem long, it happens within milliseconds.
If a website is secured with an SSL certificate, you'll see "HTTPS" (Hypertext Transfer Protocol Secure) in the URL. If there's no SSL certificate, only "HTTP" appears, without the "S" for "Secure." A padlock icon is also displayed in the address bar, representing trust and assuring visitors of the site's security.
To view the details of an SSL certificate, you can click on the padlock icon in the browser's address bar. SSL certificates typically include the following details:
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The domain name for which the certificate was issued
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The individual, organization, or device it was issued to
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The Certificate Authority that issued it
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The Certificate Authority’s digital signature
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Associated subdomains
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The certificate’s issue date
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The certificate’s expiration date
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The public key (the private key is not shown)
Why is an SSL Certificate Necessary?
Websites need an SSL certificate to keep user data secure, verify website ownership, prevent attackers from creating fake versions of the site, and build trust with users.
If a website asks users to log in, enter personal information like credit card numbers, or access confidential data such as health or financial records, it's essential to protect that data. SSL certificates help ensure that online transactions remain private and give users confidence that the website is authentic and secure enough to share personal data.
For businesses, the main importance of an SSL certificate is enabling the HTTPS address. HTTPS is the secure version of HTTP, meaning website traffic is encrypted with SSL. Most browsers now mark HTTP websites without SSL certificates as “Not Secure.” This sends a clear warning to users that the site may not be safe, encouraging businesses that haven't yet made the switch to HTTPS to do so.
