What is an SSL certificate and do I need one?

In the digital era, where cyber attacks are happening every day, securing online communications has never been more critical. As a website support manager with years of experience navigating the complexities of website security, I’ve witnessed firsthand the evolution of security protocols and the pivotal role of SSL certificates in safeguarding online interactions.

In this comprehensive guide, I’ll explain the significance of SSL certificates, and take a look into the various options available, and spotlight the revolutionary impact of Let’s Encrypt in democratising web security. It’s a technical topic, but I’ve made it as easy to understand as possible!

What is an SSL Certificate?

An SSL (which stands for Secure Sockets Layer) certificate is a digital certificate that serves as a security protocol on the Internet. It enables encrypted communication between a web browser and a web server, ensuring that all data passed between them remains private and integral. This is crucial for protecting sensitive information such as credit card numbers, personal details, and login credentials from being intercepted by thieves or bots.

When a website has an SSL certificate installed, the HTTP (this stands for HyperText Transfer Protocol for those interested!) changes to HTTPS (HyperText Transfer Protocol Secure), where the ‘S’ stands for ‘Secure.’ You’ll often also see a padlock icon next to the website’s URL in the browser’s address bar, signalling that the connection is secure.

The process of establishing a secure connection involves an ‘SSL handshake’ between the browser and the server. Here’s a simplified breakdown of how SSL certificates work:

  • The browser connects to a web server (website) secured with SSL (HTTPS). The browser requests that the server identify itself.
  • The server sends a copy of its SSL certificate to the browser. This certificate contains the server’s public key necessary to start the secure session.
  • The browser checks the certificate against a list of trusted CAs (Certificate Authorities). If the browser trusts the certificate, it creates, encrypts, and returns a session key using the server’s public key.
  • The server decrypts the session key using its private key and returns an acknowledgment encrypted with the session key to start the encrypted session.
  • Server and browser now encrypt all transmitted data with the session key.

This encrypted data is virtually impossible for hackers to decipher without the unique session key, ensuring that your information remains secure and confidential.

SSL certificates also serve a secondary function of authentication and trust. They verify that the server you’re connecting to indeed belongs to the organisation it claims to represent. This is done through a rigorous validation process conducted by Certificate Authorities (CAs), the entities responsible for issuing SSL certificates. Depending on the level of validation, the certificate can confirm basic domain ownership or provide more extensive verification of the organisation’s identity.

In essence, an SSL certificate is not just a technical tool for encryption; it’s a critical component of web security that protects data, verifies server integrity, and enhances user trust and confidence in the internet.

The Role of SSL in Modern Web Security

The adoption of SSL certificates has soared in recent years, propelled by growing awareness of cybersecurity threats and stringent regulatory demands. Search engines and web browsers have also championed SSL, with Google, for instance, marking non-SSL websites as “Not Secure.” This move underscores the critical nature of SSL in establishing credibility and trustworthiness online for internet users.

Not Secure SSL Warning

SSL certificates do more than just encrypt data; they also validate the identity of the website owner, offering users peace of mind that they’re interacting with a legitimate and secure site. This dual function of encryption and validation is what makes SSL certificates indispensable in the quest for a safer internet.

Different Types of SSL Certificate

SSL certificates come in various forms, each tailored to different security needs and organisational requirements. Understanding these options will help you choose the right certificate for your website.

Domain Validated (DV) Certificates

DV certificates offer a basic level of security, verifying only the ownership of the domain. They are issued quickly, often within minutes, making them a popular choice for small websites and blogs that require encryption but do not handle sensitive data and only need to prove domain ownership.

Organisation Validated (OV) Certificates

OV certificates provide a higher level of security by validating not only the domain ownership but also the organisation’s identity. This involves a more rigorous vetting process, requiring website owners to furnish official documents that prove their business is legitimate and trustworthy. OV certificates are suited for businesses and organisations that deal with moderately sensitive data, who need to keep that data secure.

Extended Validation (EV) Certificates

EV certificates offer the highest level of security and trust. The issuance process for an EV certificate is the most stringent, involving a thorough examination of the organisation’s legal, operational, and physical existence. Websites with EV certificates display a prominent green address bar or a lock icon with the organisation’s name, offering users the highest assurance of security and authenticity. These certificates are ideal for financial institutions, e-commerce sites, and any organisation that handles highly sensitive data.

Free SSL certificates – Let’s Encrypt

Since 2016, a project called Let’s Encrypt has transformed the landscape of web security by offering free, automated, and open SSL/TLS certificates. This non-profit initiative aims to make encrypted connections universally available, eliminating cost and complexity barriers that previously prevented many website owners from adopting SSL.

Before Let’s Encrypt, obtaining an SSL certificate was a costly and sometimes complex process that deterred small website owners. Let’s Encrypt changed the game by providing a streamlined, automated process that allows for the easy deployment of SSL certificates, making secure connections accessible to everyone.

Its impact has been profound, significantly increasing the percentage of websites using HTTPS and thereby making the web a safer place for users and businesses alike.

Choosing the Right SSL Certificate: Pros and Cons of Each Type

In my years of managing website security, I’ve navigated the maze of SSL certificate options numerous times. Each type brings its own set of advantages and challenges, tailored to different security needs and organisational requirements.

Here’s a closer look at the pros and cons of Domain Validated (DV), Organisation Validated (OV), and Extended Validation (EV) certificates, based on my personal experience.

Pros and Cons of Domain Validated (DV) Certificates


  • Speed: DV certificates can be issued within minutes, making them ideal for quick deployments. In scenarios where a new blog or a basic informational site needs to go live with HTTPS, DV certificates offer an expedient solution.
  • Cost-Effective: Being free or relatively inexpensive, DV certificates are a great starting point for small businesses and personal sites looking to secure their domain without a significant financial outlay.
  • Easy: The automated validation process, especially with services like Let’s Encrypt, simplifies management, making it less daunting for website owners with limited technical expertise.


  • Limited Trust: DV certificates verify only the domain ownership, not the legitimacy of the organisation behind the site. This can be a drawback for websites that handle more sensitive user interactions, where higher assurance for visitors is desired.
  • Perception Issues: Some users and entities perceive DV certificates as less secure due to their minimal validation process, which can affect the credibility of a website, especially in industries where trust is paramount.

Pros and Cons of Organisation Validated (OV) Certificates


  • Enhanced Trust: OV certificates offer a higher level of trust by validating the organisation’s identity. This additional verification reassures users that they’re dealing with a legitimate entity, which is crucial for websites that collect personal information.
  • Better Brand Perception: The presence of an OV certificate can enhance the perception of a website as being more secure and professionally managed, reflecting positively on the brand.
  • Moderate Pricing: While more expensive than DV certificates, OV certificates are reasonably priced, making them accessible for many medium-sized businesses.


  • Longer Issuance Time: The validation process for OV certificates is more extensive than for DV certificates, requiring additional documentation. This can lead to longer issuance times, which might be a hindrance for projects with tight deadlines.
  • Complex Management: The need to periodically validate organisational details can add an administrative layer, requiring more effort in certificate management and renewal.

Pros and Cons of Extended Validation (EV) Certificates


  • Maximum Trust and Security: EV certificates provide the highest level of validation, offering users the utmost confidence in the website’s security and the legitimacy of the organisation behind it. The distinctive visual cues, like the green address bar or the organisation’s name displayed in some browsers, are significant trust signals.
  • Increased Conversion Rates: For e-commerce sites and online businesses, the increased trust factor can directly translate into higher conversion rates, as customers feel more secure in making transactions.
  • Fraud Protection: The rigorous vetting process for EV certificates makes it much harder for phishing sites to impersonate your website, offering an additional layer of protection against fraud.


  • Higher Cost: EV certificates are the most expensive option, which can be a significant consideration for smaller businesses or startups.
  • Lengthy Validation Process: Obtaining an EV certificate can be a lengthy process, sometimes taking weeks, due to the thorough verification of legal and operational existence. This can be a major drawback for businesses needing immediate security solutions.
  • Diminishing Visual Cues: With evolving browser designs, some of the distinct visual indicators of EV certificates, like the green address bar, have become less prominent, potentially reducing their impact on user perception.

Choosing the right SSL certificate requires an understanding of your website’s specific needs and balancing them against the pros and cons of each certificate type. In my experience, DV certificates are a no-brainer for new, small-scale projects where quick deployment and minimal costs are key.

For established businesses where user trust is crucial, investing in an OV certificate has proven to be a wise middle ground, offering a solid level of validation without breaking the bank. Meanwhile, for high-profile projects, particularly in the financial or e-commerce sectors, the credibility and trust conferred by an EV certificate are invaluable, despite the higher cost and longer issuance time.

SSL Certificate Management Tips

Adopting SSL certificates is just the first step in securing your website. Proper management and maintenance are crucial to ensuring ongoing security and trustworthiness. Here are some best practices:

Regularly Update and Renew Certificates

SSL certificates are not perpetual. They come with expiration dates that can range from a few months to a few years, depending on the issuing certificate authority and the type of certificate. An expired certificate can lead to significant issues, including loss of customer trust, decreased website traffic, and negative impacts to your site’s SEO rankings.

  • Set Calendar Reminders: One of the simplest yet most effective strategies is to set calendar reminders for your certificate’s expiration dates. I recommend setting the first reminder at least a month before the expiry date, giving you ample time to take action.
  • Automate Renewals: Many SSL providers and web hosting services offer automatic renewal services. Enabling this feature can ensure your certificate never lapses, removing the need for manual monitoring.
  • Regular Audits: Conduct regular audits of your SSL certificates to ensure they are up-to-date and have not been revoked. This is crucial for websites with multiple subdomains or third-party integrations.

Leverage Monitoring Tools

Utilising tools designed for monitoring and managing web security can provide an extra layer of assurance.

  • Uptime Robot: This tool monitors your website’s uptime but can also be configured to alert you if your SSL certificate is close to expiring. Such real-time alerts can be invaluable, especially for websites with high traffic volumes or those conducting e-commerce.
  • SSL Labs’ SSL Test: Regularly use tools like SSL Labs’ SSL Test to evaluate your website’s SSL configuration and security level. It provides a comprehensive overview of your SSL certificate’s performance and security features, highlighting areas for improvement.


Do I need an SSL certificate?

The short answer is yes, an SSL certificate is essential for virtually every website. Beyond encrypting data to protect sensitive information, having an SSL certificate is crucial for building trust with your visitors. In today's digital landscape, users expect a secure and private online experience, and browsers prominently mark non-HTTPS sites as "Not Secure," which can deter visitors and harm your site's credibility. Furthermore, SSL certificates contribute to higher search engine rankings, as search engines like Google give preference to secure websites. Whether you're running a personal blog, a small business site, or a large e-commerce platform, an SSL certificate is a fundamental component of your website's security and online presence.

How do I choose between a free SSL certificate and a paid one?

Free SSL certificates, like those offered by Let's Encrypt, are ideal for blogs, personal websites, and small businesses needing basic encryption. Paid certificates often come with added benefits such as extended validation, warranty against misuse, and support. Choose a paid certificate if you run a larger e-commerce site or handle sensitive information and need the highest level of trust and security.

What are wildcard SSL certificates and when should I use them?

Wildcard SSL certificates secure your domain and an unlimited number of its subdomains with a single certificate. They're ideal for businesses managing multiple subdomains (like payment.yoursite.com, login.yoursite.com). Use them to streamline management and reduce costs compared to purchasing individual certificates for each subdomain.

Can an SSL certificate improve my website’s search engine ranking?

Yes, Google has confirmed that HTTPS is a ranking signal. Websites with SSL certificates may see a slight ranking boost in search results, as Google prioritises secure websites to ensure a safer browsing experience for users.

What happens to my website if my SSL certificate expires?

If your SSL certificate expires, browsers will display a security warning to visitors, indicating that the connection is not secure. This can deter users from accessing your site, harm your reputation, and potentially affect your SEO rankings.

How do SSL certificates work with content delivery networks (CDNs)?

When using a CDN, you must ensure the CDN supports SSL/TLS for your content to be securely delivered over HTTPS. Most CDN providers offer options to use a shared SSL certificate, bring your own certificate, or purchase one directly through the CDN.

What's the process for renewing an SSL certificate?

The renewal process can vary by provider but generally involves generating a new CSR (Certificate Signing Request), completing the validation process as with the initial certificate, and then installing the new certificate on your server. Automation tools and services can simplify renewals.

Can I transfer an SSL certificate from one server to another?

Yes, you can transfer an SSL certificate between servers. The process involves exporting the certificate and its private key from the current server and importing them into the new server. The exact steps depend on the server platforms involved.

How do multi-domain SSL certificates work?

Multi-domain SSL certificates, also known as SAN (Subject Alternative Name) certificates, secure multiple domain names and subdomains with a single certificate. They're ideal for businesses with multiple branded sites, saving the effort and expense of managing multiple certificates.

What are the implications of SSL for website performance?

While SSL/TLS encryption adds a small overhead to web server processing, modern algorithms and hardware have minimised this impact. Techniques like session resumption, OCSP stapling, and TLS 1.3 have further reduced the latency associated with SSL, making it pretty negligible for most websites in my experience.

How do I troubleshoot common SSL certificate errors?

Common SSL errors include expired certificates, domain mismatches, and untrusted certificate authorities. Troubleshooting involves checking the certificate's validity, ensuring the domain name matches the certificate, and verifying the certificate chain. Browser developer tools and online SSL checkers can help diagnose any issues you may have.

What is the role of Certificate Authorities (CAs) in the SSL ecosystem?

CAs are trusted entities that issue SSL certificates. They verify the identity of entities requesting certificates and vouch for their authenticity. The reputation of a CA affects the trustworthiness of its certificates; thus, choosing a reputable CA is crucial.

How does SSL/TLS work with email servers and other non-web protocols?

SSL/TLS can secure email communications and other protocols (FTP, IMAP, SMTP) by encrypting data transmitted between clients and servers. Configuring SSL/TLS involves installing certificates on the email server and ensuring email clients are set up to use secure connections.

What are the legal or regulatory implications of SSL certificates for businesses?

Certain industries and regulations (like HIPAA for healthcare and PCI DSS for payment card data) mandate the use of encryption to protect sensitive data. Businesses must comply with these requirements, which often involve using SSL/TLS for secure data transmission.

How do browser updates affect SSL certificate compatibility?

Browsers periodically update their security policies and supported encryption algorithms. To maintain compatibility, ensure your SSL/TLS certificates use up-to-date algorithms and follow best practices for configuration. Regularly testing your site with multiple browsers can help identify potential compatibility issues.


SSL certificates are a cornerstone of website security, essential for protecting data, validating identities, and building trust online. The advent of Let’s Encrypt has significantly broadened access to SSL, but choosing the right certificate type and adhering to best practices in certificate management remain crucial.

As we navigate the ever-evolving landscape of cyber threats, the importance of SSL certificates in safeguarding online interactions cannot be overstated. By embracing these technologies and standards, website owners can ensure a secure and trustworthy internet for all users.

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About the Author

lee murphy - support manager

Lee M

Support Manager

With over a decade of technical expertise, our Support Manager Lee brings a wealth of knowledge and skill to our team, ensuring our client’s websites function properly and thrive. 

Lee’s role is to help make sure our client’s websites website stay online by looking after both the website’s health and our hosting. Helping to keep our clients’ websites online when they’re needed most. He has been in the marketing industry since 2010 but has been involved with coding since school.

Outside of work, Lee is a keen fan of video games and card games even travelling across the country to compete.