SSL: How Does It Work?

Cybercrime has hit an all-time high, with hackers exploiting recent technological advancements. By 2025, the global cost of cyberattacks is projected to reach $10.5 trillion yearly. One of the root causes of this growing problem is the lack of strong website security measures in place. This essentially leads to data breaches, identity theft, and lost visitor trust. 

As a website owner, you can battle these attacks by using the Secure Sockets Layer (SSL) protocol. In this article, we’ll explore what SSL is and how it works to protect your site from cyber threats. 

What is SSL and what is its function? 

The SSL protocol encrypts data transferred between devices on a network. This is to prevent sensitive information from being exposed to anyone trying to intercept it. 

Though SSL initially set the standard for online security, it has since been replaced by a newer security protocol called Transport Layer Security (TLS). However, both SSL and TLS have the same core function: to keep data safe by encrypting it before sending it across the web. That’s why most people still refer to it as SSL. 

How does SSL work? 

When a user connects to an SSL-secured site, a process called the TLS/SSL handshake takes place. This setup enables the user’s browser and the website server to create a shared secret key, which allows them to communicate with each other securely. 

The TLS/SSL handshake process 

Step 1: ClientHello. The handshake starts when the client sends a ‘ClientHello’ message to the web server. It includes important details, such as the following:

• • • TLS/SSL version the client supports 

• • • List of cipher suites it can use (cipher suites determine the encryption method that will be used) 

• • • Arbitrary string of numbers called ‘client random’ 

Step 2: ServerHello. Then, the server responds with a ‘ServerHello’ message, which contains the following information:

• • • Server’s public key 

• • • Server’s SSL certificate 

• • • Session identifier or SID (identifies communication sessions between the client and the server) 

• • • Chosen cipher suite (picked from the list the client sent) 

• • • Random numeric string known as the ‘server random’

Step 3: Certificate authentication. Afterward, the client authenticates the server’s identity by checking its SSL certificate. To do this, it contacts the Certificate Authority (CA) that issued the document to confirm its legitimacy. This step guarantees that the client is connecting to a trusted server. 

Step 4: ClientKeyExchange. After the certification is validated, the client creates a random piece of data called the ‘premaster secret.’ This information is encrypted with the server’s public key and is sent to the server. 

Step 5: Decryption by the server. Once the premaster secret is received, the server decrypts the data using its own private key. 

Step 6: Creating the shared secret. The client and server use the premaster secret, along with the client and server randoms, to generate a shared secret key. This key will encrypt and decrypt all data exchanged between them during the session. 

Step 7: Client finished message. To confirm that the client’s part of the handshake is complete, it uses the shared secret key to send an encrypted ‘finished’ message to the server. 

Step 8: Server finished message. Then, the server replies with its own encrypted ‘finished’ message. 

Step 9: Secure communication. At this point, the handshake is complete. Both the client and server now use the same secret key, allowing them to communicate safely. 

Asymmetric encryption vs symmetric encryption 

The main difference between asymmetric and symmetric encryption lies in how they use keys to secure data. 

Asymmetric encryption 

This type of encryption, also known as public key cryptography, is used during the initial interaction of a client and a server. In this process, two different keys are used—the public and private keys—to establish a secure session between the devices. This approach provides security because only the server with the right private key can decipher the data. 

Symmetric encryption 

In symmetric encryption, the client and the server use a shared key, also called a session key, for both encrypting and decrypting data during a single communication session. Since the same key is used on both ends, this method is faster and ideal for ongoing data exchange within a secure connection. In essence, once the connection is established with asymmetric encryption, the communication switches to symmetric encryption. 

Why does SSL matter to website owners? 

SSL is crucial for site owners because it protects your webpage against cyber threats, builds trust among visitors, and improves your search visibility. 

Firstly, SSL is critical for defending against cyber threats. Without SSL, hackers can intercept data shared on your site, which puts users’ sensitive information at risk. SSL makes information unreadable to malicious actors and significantly reduces the risk of data breaches. 

Secondly, SSL displays the padlock icon and ‘https’ (HyperText Transfer Protocol Secure) in the URL when users visit your site. These indicators reassure them that your page is safe and secure. Because of this, they’ll feel encouraged to stay, engage, and make purchases on your website. 

Finally, search engines like Google prefer SSL-secured sites. This means that they’ll likely appear higher in search results. Ultimately, this increased visibility will help you attract more organic traffic and potential customers. 

How can you add SSL to your site? 

Adding SSL to your website is straightforward and involves a few essential steps: 

Step 1: Choose an SSL certificate. There are various types of SSL certificates available, including Domain Validation (DV), Organization Validation (OV), and Extended Validation (EV) certificates. A DV certificate is sufficient for most small sites, while larger or eCommerce sites might prefer OV or EV for added security. 

Step 2: Buy the SSL certificate. Purchase your SSL certificate from a trusted Certificate Authority (CA) like Comodo or DigiCert. Some web hosting providers also offer SSL certificates as part of their hosting packages. 

Step 3: Install the certificate. After you get the certificate, you need to install it on your web server. Many hosting providers have easy installation tools, or they can help set it up for you. If you’re using a platform like WordPress, there are also plugins that can assist you with SSL setup. 

Step 4: Update your site’s URLs to HTTPS. Once your SSL is active, make sure your website URLs use ‘https’ instead of ‘http.’ Most platforms let you update this in the settings. You can also set up redirects so users are automatically directed to the updated and secure version of your site. 

Step 5: Check for mixed content. Ensure that all assets on your site, like images and scripts, are served over HTTPS. Mixed content warnings appear if some resources still use HTTP, which can compromise your site’s security. 

Rest easy knowing you’re secure with SSL 

Don’t let hackers be the only ones who can take advantage of digital innovations. Be proactive and make the most of SSL for your website. 

Through this guide, you’ve learned that SSL is a security protocol that protects sensitive information being exchanged on your site. Apart from that, SSL fosters trust with your visitors and helps your site achieve high search rankings. 

Begin investing in your website’s security today with Domain.com. We provide SSL certificates and SiteLock security that are guaranteed to strengthen your site’s defenses against cyberattacks. 

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