What is SSL? How does it work, and why do I need it?

When registering a domain or creating a website, you’ll quickly encounter the term SSL. But what exactly is it, and do you need it too?

Secure Sockets Layer, short SSL, ensures the secure transmission of data on the internet.

It protects personal data, such as passwords or credit card information, from being intercepted by third parties by establishing an encrypted connection between the web browser and the server. For websites, SSL is indispensable, as it not only enhances data security but also strengthens user trust and positively impacts SEO rankings.

What is the difference between SSL and TLS?

You might often see the term TLS (Transport Layer Security) alongside SSL. But what’s the difference?

TLS certificates are simply the current and more reliable successors to SSL certificates. However, the term SSL has gained wider acceptance in the context of security certificates, which is why we will continue to use SSL in the following. Today, the two terms are often used synonymously. When someone refers to an SSL certificate, they are typically talking about a TLS certificate.

What is an SSL certificate?

An SSL certificate verifies the identity of a website and contains information such as the domain name, the issuer, and the validity period. Essentially, it’s like an ID card for your website.

Every browser can check the authenticity and validity of a certificate and provide information about whether the accessed page was transmitted securely. This allows users to verify whether their data is protected from third-party access.

What types of SSL certificates are there?

SSL certificates come in various security levels, containing different amounts of information:

Domain Validation (DV): The validation focuses solely on the domain and is the simplest form of certification. The certification authority (CA) only checks whether the applicant actually has technical access to the domain, typically via email verification or by uploading a file to the server.

Organization Validation (OV): In addition to domain control, the organization is also verified to ensure it is legally accountable. This involves checking addresses, phonebook entries, and public business directories.

Extended Validation (EV): This is the highest security level, where the organization’s identity undergoes comprehensive verification. Among other requirements, a definitive proof of the business location is needed.

How does SSL encryption work?

When a domain is accessed, an authentication process is initiated between the web browser (client) and the server. This process is called a “handshake.”

When you visit a website, the browser requests identification and retrieves the SSL certificate from the server. The browser checks the certificate’s Certificate Authority and validity, then sends a positive response if everything is in order. The connection is then established. By retrieving the certificate, it verifies that the server and the accessed domain belong together.

Graphic showing the requests between server and client during the SSL handshake.

The actual encryption (up to version TLS 1.2) uses public and private keys, which together generate a unique session key. The Client creates and sends a “pre-master secret” (a random sequence of data) and encrypts it with the public key, which is part of the certificate. Then the server decrypts the “pre-master secret” using its private key. Both the client and the server can now generate the secret session key, which is used to encrypt the ongoing communication.

Graphic showing the SSL encryption process with the various keys

Why do I need SSL?

SSL is essential not only for online shops where personal data is transmitted but also for other types of websites. It offers numerous advantages for both websites and their users.

The most important benefit is the secure transmission of sensitive data. Encryption ensures this data is protected from unauthorized access and hacker attacks. Initially, data on the web was transmitted in plain text, meaning intercepted messages could be read by anyone. When entering credit card numbers during a transaction, for example, this information was transmitted unencrypted over the internet. SSL was developed to address this issue and safeguard user privacy. It encrypts all data exchanged between users and the web server, making intercepted data unreadable without the decryption keys.

An SSL certificate also boosts user trust in a website and signals credibility, supported by the padlock symbol in the browser. Additionally,  „https“ in the URL indicates an SSL-secured website.

Moreover, search engines like Google prefer HTTPS websites, providing a ranking advantage for sites with SSL certificates. Google Chrome even marks websites without valid SSL certificates as unsafe and displays a warning when such a site is accessed.

SSL is, therefore, not only relevant for online shops or forms but also for websites that don’t process payments or collect sensitive data. It is indispensable for all website operators to meet data protection requirements and enhance security and the user experience.

Conclusion: That’s why SSL is so important!

SSL is an essential standard for secure and trustworthy websites. It protects sensitive data from theft, improves security, and fulfills important data protection requirements. An SSL certificate not only enhances user trust but also offers SEO advantages. Whether for online shops, blogs, or business websites, encrypted data transmission is a must today.

Check out our range of certificates here to find the right one for your needs!

I hope you enjoyed this article. Want to learn more about domains? Take a look at our article on What is a Top-Level Domain.

If you have any questions, feel free to email us at blog@inwx.de.