What Is SSL? Your Guide to Secure Sockets Layer

I remember learning about cryptography in elementary school. Ancient Egyptians used encrypted hieroglyphics to hide a message’s true meaning from those who didn’t know how to decipher the code. Modern encryption accomplishes the same thing but over the internet. One of these forms of encryption is Secure Sockets Layer, or SSL for short.

SSL is a protocol used on computer networks to secure communications with encryption.

When a browser and server communicate, SSL generates an encrypted connection between them. All data sent through that connection remains private.

The SSL protocol was improved upon to create Transport Layer Security (TLS), so SSL isn’t technically used anymore. However, the term SSL is still used regularly to refer to network encryption.

As a form of web security, SSL plays a major role in protecting data transfers from malicious actors. The SSL protocol (and the TLS protocol) helps websites build trust and secure sensitive information such as credit card data, contact information, and login credentials.

The SSL protocol has a strong development history. Learn about its history, starting with its development by Netscape, then explore how TLS took its place.

We’ll also discuss the differences between SSL and TLS.

History of SSL

Developed by Netscape Communications in the mid-1990s, the earliest version of Secure Sockets Layer was never actually released. Due to security issues, the public never saw SSL 1.0.

The next version, SSL 2.0, also had problems with security, yet its release in 1995 began SSL’s true introduction to the world. In 1996, Netscape released SSL 3.0, which improved upon its past security flaws. This is the version that drove widespread adoption.

TLS, or Transport Layer Security, built upon the technology from SSL and began replacing SSL in 1999. The introduction of TLS by the Internet Engineering Task Force, or IETF, improved areas of SSL such as security and encryption.

SSL vs. TLS

SSL and TLS are both protocols for the cryptographic movement of data over networks. The SSL protocol preceded TLS; therefore, TLS is seen as the more modern, secure internet encryption protocol.

TLS was built upon SSL, using many of the former protocol’s features. But TLS improves upon SSL.

Those improvements include:

• Stronger performance
• Enhanced security features
• More advanced encryption algorithms

For example, TLS has superior message authentication and key exchange methods compared to SSL. Despite all that, many companies and individuals still refer to TLS as SSL.

That’s because people are familiar with SSL, and many software companies and libraries already have the term “SSL” in their documentation or even company names. So, the term stuck, even though TLS replaced the technology.

For most internet users, it’s enough to know about the basic functionality of SSL. Network professionals, however, should dive into its encryption mechanisms, certificates, and how those certificates get issued.

Basic Functionality

SSL forms a connection between a client and a server. Often, the client is the user’s web browser. To establish this connection, a “handshake” takes place between the server and the client.

Here’s how the handshake process works:

1. Client Hello: The client says “hello” to the server. This message also indicates supported encryption options.
2. Server Hello: The server replies with a message saying “hello.” It decides the proper encryption method from its options.
3. Exchange of Certificate: The server also replies with its digital security certificate for the client to authenticate.
4. Generation of Key: Both the server and client create unique keys, called session keys, to establish an encrypted communication portal.

As a result of the handshake, SSL and TLS generate a connection that maximizes data integrity and privacy.

Encryption Mechanism

SSL uses two types of encryption mechanisms to establish secure data transmissions: symmetric and asymmetric.

• Symmetric: The fastest but less secure encryption option. Symmetric encryption uses one key to handle both encryption and decryption.
• Asymmetric: This is a slower but more secure mechanism for exchanging keys. It uses two keys: one public and one private. The public key handles encryption, and the private key handles decryption.

Public and private keys have specific roles in SSL encryption. While the SSL handshake occurs, the asymmetric encryption transports the symmetric key securely so they work together. Then, the server uses its public key to decrypt the received session key.

After that, the connection mainly uses the session key for faster symmetric encryption.

Certificates

Certificate Authorities, or CAs, are third-party organizations responsible for validating and issuing digital certificates in the SSL and TLS protocols.

Certificate Authorities strengthen security by validating the authenticity of each server’s public key and preventing threats such as man-in-the-middle attacks.

Different types of SSL certificates:

• Domain Validated (DV): Best for small websites since DVs offer basic validation and speedy issuance. They only confirm domain ownership.
• Organization Validated (OV): Useful to show an increased level of trust thanks to its moderate level of validation and its verification of both organizational and domain ownership details.
• Extended Validation (EV): Has the highest level of trust due to its extensive validation process. EV certificates confirm an organization and domain’s operational, physical, and legal existence. They also show a green address bar in the browser.

Certificate Authorities confirm each applicant’s identity before issuing a certificate. The depth of that confirmation depends on the type of certificate (as outlined above).

Then, the CA takes the certificate and signs it with a private key to validate its authenticity. This issuance and validation process ensures a highly secure communication portal.

Before implementing an SSL certificate on your website, it pays to know about the benefits of SSL. This way, you understand the importance of opting for a web host that provides SSL certificates.

Enhanced Security

The secure communication channel established by SSL enhances security for a website, its owner, its visitors, and the entire internet.

SSL maximizes data security by encrypting all communications.

This prevents threats such as eavesdropping, man-in-the-middle attacks, and data tampering.

It also promotes trust and confidentiality in the relationship between servers and clients.

By authenticating the server’s identity, SSL ensures users are communicating with the legitimate site and not an imposter. This can thwart phishing attempts or other common types of online fraud.

Essentially, SSL encryption safeguards sensitive data from being intercepted or altered by unauthorized actors.

Improved SEO

Most websites want to improve search engine rankings, so it’s important to know SSL protection is known to boost rankings in Google and other search engines.

Search engines prefer to show secure websites, making for a safer internet.

Additionally, users are more likely to trust your website, which shows Google that people aren’t afraid of using your site.

When search engines detect SSL certificates, they interpret it as a signal that the website is taking security seriously. In turn, it enhances the site’s reputation which results in a higher ranking position in search results.

Higher rankings typically mean more engagement, which is a win-win for everyone.

User Trust and Credibility

A website with an SSL certificate displays two trust indicators in the browser: “https” before the URL and a padlock icon in the address bar.

Users have come to expect these two elements when visiting websites.

They’re associated with safety, legitimacy, and confidence — and many browsers display large warnings if your site lacks an SSL certificate.

These visual cues are simple yet important signals for safety and security.

This type of assurance is especially crucial for eCommerce sites that handle sensitive customer data, including credit or debit card information.

Data Integrity

SSL protects against data theft, but what about data integrity?

Many website owners forget that a bad actor could also modify transmitted data if it is left unprotected.

Thanks to data encryption, an SSL certificate blocks unauthorized data alterations, ensuring that the data remains authentic and unchanged.

When data is transmitted over an SSL-secured connection, it’s encrypted so that only the intended recipient can decode and read it.

For example, if you want to log into your bank account to transfer money, the bank’s server will decrypt the information using a private key.

All website owners should implement SSL/TLS on their sites. Luckily, many hosting providers already have them installed. Others provide them for free but require you to activate the certificates. We’ll show you how to choose and implement SSL in the steps below.

Choosing the Right SSL Certificate

Choosing the perfect SSL certificate depends on what you want it to do. Some websites don’t require extensive validation, but sometimes you need the utmost security. The different certificate types change those security levels.

Domain Validation (DV)

Domain Validation certificates work best for smaller websites and blogs. The validation and issuance processes are streamlined, and you get basic encryption. Each DV offers the validation of domain ownership via DNS records or email.

Consider a DV for a smaller website, to save money, and to get the certificate quickly. Avoid DVs if you want higher trust levels (through organizational identification). For instance, most eCommerce stores would want a higher level of security.

Organization Validation (OV)

An OV, or Organization Validation, certificate completes the same domain ownership verification as a DV but adds an extra layer of security by verifying the organization’s identity. We recommend OVs for business websites, particularly eCommerce stores.

Anything beyond a personal website or blog should use an OV certificate. The issuances are slower than with a DV, but there’s more credibility, user trust, and security with OV certificates.

Extended Validation (EV)

An Extended Validation certificate, or EV, provides the highest level of user trust and security from an SSL certificate. That’s because of its verification of an organization’s operational, legal, and physical existence.

EV certificates receive a green address bar within browsers, and they help prevent phishing attacks. Although an EV takes longer to get and is more expensive, organizations that demand the utmost protection and credibility should opt for one.

Free vs. Paid Certificates

Many web hosts offer free SSL certificates through services like Let’s Encrypt. Almost all free certificates are Domain Validation certificates, so they offer basic encryption and protection for personal blogs and very small websites. They’re free and easy to obtain but often lack customer support.

OV and EV certificates fall under the paid category, which you can purchase from companies like SSLTrust. They’re worth the premium for companies that need to prevent data breaches, increase security, and show the highest level of trust to their customers.

They obviously cost more than the free options — and can take some time to obtain — but they’re essential for commercial websites.

Steps to Implement SSL

Follow these steps to implement SSL on your website:

1. Purchase a certificate: Use a reputable Certificate Authority to buy an SSL certificate. You can often choose from DV, OV, and EV certificates.
2. Install the certificate: Some CAs and hosting providers offer one-click buttons to install certificates on your server. Otherwise, ask your provider how to upload it to the server.
3. Configure the server for SSL: Ensure your server has HTTPS activated. It should listen on port 443 in order to use the appropriate certificate.
4. Update all internal links and resources: Internal links won’t change automatically to the new HTTPS URLs. You must modify them yourself. Some platforms, such as WordPress, offer plugins to automate the process. You should also change links to resources like images.

Once implemented, it’s important to examine some of the common pitfalls that come with using SSL. The following section guides you on how to troubleshoot those issues.

Common Pitfalls and Troubleshooting

The most notable pitfalls you may encounter with SSL include expired certificates and mixed content issues.

In the world of SSL/TLS, best practices lead to higher levels of security, greater user trust, and the minimization of pitfalls discussed in the previous section.

Follow these best practices — such as regular updates, monitoring, and advanced security measures — for a smooth SSL experience.

Regular Updates and Renewals

To maintain secure connections and to increase user trust, it’s imperative to complete regular updates and renewals of all SSL certificates.

Expirations trigger browser warnings when visitors come to your site, which is scary for users and could cause a decline in search engine rankings.

It’s best to implement automation for SSL updates and renewals. This prevents any human error or lapses in memory to renew or update.

Consider tools like Certbot for automating renewals, or see if your hosting provider has an automated solution.

Monitoring and Management

Always maintain a consistent SSL monitoring schedule.

Monitoring SSL certificates prevents vulnerabilities, ensures you update/renew certificates, and maintains consistency with security policies.

Tools such as Certbot, Nagios, and SSL Labs assist with SSL monitoring and management.

For managing several SSL certificates on multiple domains, look into tools like AWS Certificate Manager or Let’s Encrypt.

Advanced Security Measures

Although some personal and smaller websites only require basic SSL protection, anything beyond that demands more advanced security measures.

To start, consider adding an HTTP Strict Transport Security (HSTS) policy that forces browsers to use HTTPS.

An HSTS policy forces secure connections and blocks downgrade attacks (attacks that wait for browsers to serve up HTTP versions).

Another advanced security measure is a Content Security Policy (CSP), which fights code injection attacks like cross-site scripting. It does this by only identifying trusted content sources.

The future of SSL/TLS is promising thanks to evolving developments in encryption technology and historically successful advancements like the shift from SSL to TLS.

However, the effectiveness of encryption is uncertain, considering quantum computing could actually break encryption algorithms.

Even though it has technically evolved into something new (TLS), SSL is still the acronym of choice for encrypting communications online.

In this article, you’ve learned about the evolution of SSL, its relation to TLS, and how the different types of SSL certificates work to protect your website and its users.

With the knowledge of how to implement SSL on your site and maintain it well into the future, we encourage you to continue learning about SSL and maintain an up-to-date relationship with new encryption technology.

That’s especially true since quantum computing has disrupted the world of cryptographic algorithms; you may soon have to seek a more secure SSL/TLS configuration.