SSL certificate FAQs: Your comprehensive guide from basics to advanced principles
Digital certificates play an important role in shaping the modern digital ecosystem, offering a much-needed foundation of trust through the power of authentication and encryption. Many people recognize the value of these certificates but struggle to understand how they work or what it takes to protect sensitive information via SSL/TLS certificates. In this article, we break down the basics and delve into advanced insights to help you fully understand their role in digital security.
General questions about SSL certificates
If you're like many website owners or users, you are at least vaguely aware of SSL certificates. You've probably come across the padlock icon in your address bar (now a “tune” icon for Google Chrome users) or even spotted warning messages due to expired SSL certificates. The following common questions and answers reveal why SSL certificates exist and why they are so important.
What is an SSL certificate?
An SSL (Secure Sockets Layer) certificate is a digital credential that enables secure, encrypted communication between a web browser and a server. While the term "SSL" is still widely used, it has been replaced by the more secure TLS (Transport Layer Security) protocol. SSL/TLS certificates authenticate the identity of a website and ensure that any data transmitted between the website and its users is encrypted. Each certificate includes a public and private key, with the public key used to encrypt data while the private key is responsible for decrypting information.
What is the difference between SSL and TLS?
Secure Sockets Layer (SSL) and Transport Layer Security (TLS) both represent cryptographic protocols and both rely on digital certificates to authenticate website identities. While they share a similar purpose, TLS is the more advanced and secure successor to SSL, addressing vulnerabilities in SSL and introducing stronger encryption, improved performance, and enhanced security features.
Although SSL has officially been deprecated, the term "SSL" is still commonly used to refer to TLS in many contexts. Today, virtually all secure web connections rely on TLS.
Are there different encryption strengths for SSL certificates?
Encryption strength depends on the key length used during the encryption process, with 128-bit and 256-bit encryption being the most common. While both offer strong protection, 256-bit encryption is considered more secure because its longer key length results in an exponentially higher number of possible key combinations, making it more resistant to brute force attacks.
That said, 128-bit encryption is still secure and sufficient for some applications. The actual encryption strength used in an SSL/TLS connection is determined by the cipher suite negotiated during the TLS handshake between the browser and the server.
Sectigo SSL certificates meet the highest standards with 256-bit encryption.
What is a Certificate Authority (CA)?
The Certificate Authority (CA) is a third-party organization responsible for issuing and managing digital certificates that authenticate the identities of websites, individuals, or organizations. The CA verifies the identity of the certificate requester to ensure that the information provided is accurate and trustworthy.
The CA’s operations are guided by strict industry standards set by the CA/Browser Forum, an association of CAs, web browsers, and other stakeholders. These standards ensure the authenticity, reliability, and security of digital certificates. By adhering to these guidelines, CAs like Sectigo play a vital role in maintaining trust across the internet ecosystem.
What is an intermediate certificate?
An intermediate certificate serves as a bridge between the top-level root certificate and the end-entity certificate, which is ultimately issued to a specific website or organization. Issued by the root CA, the intermediate certificate plays a critical role in establishing a chain of trust that links the highly secure root certificate to the end-entity certificate.
As a key part of the trust hierarchy, intermediate certificates ensure that the end-entity certificate is recognized as valid and trusted by web browsers.
Questions on how SSL certificates work and the different types available
It is important to understand how SSL/TLS certificate processes work and the types of certificates available so you can choose accordingly.
How does SSL/TLS work step by step?
The SSL process begins with a handshake, in which the browser aims to connect with the TLS-secured server. During this handshake, asymmetric encryption is used to securely exchange a pre-master key. The browser verifies the server's digital certificate to ensure it is valid, trusted, and issued by a recognized Certificate Authority (CA).
Once the pre-master key is exchanged, it is used to generate session keys. These session keys enable faster symmetric encryption for the remainder of the session, securing all data exchanged between the client and server. When the browsing session ends, a message is sent to terminate the secure connection.
What are the different validation levels of SSL certificates?
Digital certificates are available with various validation levels. These determine the extent to which CAs vet requesting individuals or organizations. The levels of validation include:
- Domain Validation (DV). Easy and very quick to obtain, DV certificates are affordable and suitable for internal sites, test domains, and test servers. These involve a simple, one-step verification process.
- Organization Validation (OV). Moving beyond domain control to also verify the legal existence of requesting organizations, OV certificates provide a higher level of trust by confirming that the organization in question is legitimate.
- Extended Validation (EV). Known for providing the highest level of validation, EV calls for an in-depth verification process, in which details such as the company name and location are verified prior to detailed vetting procedures. This type is the industry standard for eCommerce websites.
What are the different types of SSL certificates?
In addition to being categorized based on levels of validation, SSL certificates fall into categories referencing the number of domains or subdomains they can secure.
- Single-Domain. This simple certificate is meant to secure just one domain or website, both WWW and non-WWW versions.
- Wildcard. More versatile than the single-domain certificate, the wildcard can secure one domain plus an unlimited number of subdomains under the main domain.
- Multi-Domain or Subject Alternative Names (SAN). As the most comprehensive option, the multi-domain certificate can secure several unique domains and subdomains as well.
What is a Wildcard SSL certificate?
Wildcard certificates make it possible to secure a single domain — along with an unlimited number of subdomains under the main domain — with a single certificate. This streamlines what could otherwise be a cumbersome process for securing several subdomains with individual SSL certificates. These subdomains can easily be added or removed as needed without requiring new certificates.
What is a Multi-Domain SSL certificate?
A Multi-Domain SSL certificate is designed to secure multiple, distinct domains and their associated subdomains under a single certificate. Unlike wildcard certificates, which secure one primary domain and all its subdomains, multi-domain certificates offer flexibility for organizations managing multiple websites across completely different domains.
This makes them especially valuable for businesses with diverse branding needs or those operating multiple websites on different domains, simplifying certificate management and reducing costs.
What is a Code Signing Certificate?
A code signing certificate is not the same as an SSL certificate, but it is often discussed alongside SSL/TLS certificates due to its role in establishing trust. Code signing certificates are used to digitally sign software and applications to ensure authenticity and integrity of code, verifying that it has not been altered or tampered with since it was signed by the developer. They help users trust that the software they are downloading is from a legitimate source and free from malicious modifications.
Installation and management
The process of installing and managing an SSL certificate may seem cumbersome, but a little guidance can help overcome common issues.
What are the requirements to obtain an SSL certificate?
Requirements for obtaining SSL certificates vary based on the intended validation level. In general, however, these call for the submission of a Certificate Signing Request (CSR), along with proof of domain ownership.
What is a Certificate Signing Request (CSR)?
During the process of obtaining an SSL/TLS certificate, the requester must submit a Certificate Signing Request (CSR) to the Certificate Authority. This includes the Fully Qualified Domain Name (FQDN) plus the public key and other identifying information. This additional information can include the organization name, organizational unit, locality, country and more.
How much do SSL certificates cost?
SSL certificate costs can vary considerably depending on the preferred level of validation and also, whether single, wildcard, or multi-domain certificates are needed. Single domain DV certificates from Sectigo, a trusted Certificate Authority, are available for $110 for one year. Sectigo also offers multi-year pricing options, allowing customers to secure their certificates at discounted rates over extended terms. For example, single domain DV certificates can cost as little as $88 a year over 6 years, providing considerable cost savings and convenience.
How do I install an SSL certificate on my web server?
The process of installing an SSL certificate begins with generating the CSR and submitting it to the CA. Once the certificate is issued and the file is received, it should be uploaded to the server and configured for secure communication. This process can play out differently among various services, but CAs can provide valuable guidance along the way.
How can I check if my SSL certificate is installed correctly?
To verify your SSL certificate installation, start by checking if your site uses HTTPS in the browser address bar. Clicking on the icon in the address bar can provide more details about the certificate, such as its validity period and issuer.
If you notice any issues with installation, contact your CA for further assistance.
How do I renew my SSL certificate?
Renewal is a key part of the certificate lifecycle. This can be accomplished manually by generating a new CSR, submitting it to the CA, and downloading the new certificate once issued.
Alternatively, you can streamline this process by automating certificate lifecycle management with platforms like Sectigo Certificate Manager (SCM). Automated solutions help ensure timely renewals, reducing the risk of expiration and minimizing manual effort.
Do I need an SSL certificate for each domain or subdomain?
It is important to secure every domain and every subdomain, but it is not necessary to obtain separate SSL certificates for numerous subdomains and domains. This is where multi-domain and wildcard certificates prove especially useful.
Do I need to delete old SSL certificates?
SSL certificates are no longer valid once they expire, and, at this point, it is necessary to delete or otherwise remove them. These certificates could still potentially be exploited by attackers.
Should I automate SSL certificate lifecycle management?
Manual certificate lifecycle management can be time-consuming, costly, and prone to human error, making it increasingly challenging for organizations to handle effectively. With SSL certificate validity periods becoming shorter—likely shifting to 90 days, and potentially as low as 47 days in the near future—automation is no longer just an option; it’s a necessity.
Automated certificate lifecycle management solutions, such as SCM, streamline the entire certificate lifecycle process, from issuance to renewal. These tools reduce the risk of expired certificates, improve reliability, and help organizations keep pace with the increasing frequency of certificate renewals.
Security and compliance
If one of the main purposes of the SSL is to secure websites, users, and communication, it stands to reason that those implementing SSL certificates will want to know as much as possible about security and compliance implications.
Are free SSL certificates safe to use?
Some entities issue SSL certificates free of charge. These are generally safe for basic encryption needs, but they come with significant limitations including very little customer support and DV as the only validation option.
Paid SSL certificates, on the other hand, provide advanced features such as higher validation levels (OV and EV), which ensure higher trust levels and stronger authentication. They also include comprehensive customer support, making them a far superior choice for businesses and websites that prioritize security, compliance, and user trust.
What happens if you don't have an SSL certificate?
Without SSL certificates, websites lack secure connections, leaving sensitive information highly vulnerable. Potential customers will receive warnings from browsers and will be less willing to visit websites deemed dangerous due to lack of SSL protection.
What happens when an SSL certificate expires?
If SSL certificates are allowed to expire, websites are no longer able to establish secure connections, triggering browser warnings that the site may not be safe. This can lead to numerous problems: a possible loss of customer trust, reduced website traffic, disruptions in service, and security vulnerabilities.
How long is an SSL certificate valid?
Validity periods for SSL certificates currently span around 397 days, but this is likely to change soon. There is currently a strong push for shorter lifespans in order to address escalating security concerns. In the future, validity periods may extend just 90 or even a mere 47 days.
How do I fix common SSL certificate errors?
SSL/TLS Handshake failures or errors can occur on both the client and server sides. Common client-side issues include incorrect system time, browser misconfigurations, or interference from firewalls or antivirus software. On the server side, errors may result from protocol mismatches, cipher suite incompatibilities, incorrect SNI settings, or issues with expired or misconfigured certificates.
To resolve these issues, ensure the system time is correct, use the latest TLS version and cipher suites, verify SNI configurations, and manage certificates properly with a reputable CA like Sectigo.
Additional SSL FAQs
We've answered a few additional SSL questions, addressing everything from SEO to strategies such as SSL offloading or pinning.
How do SSL certificates affect SEO and eCommerce?
SSL certificates form a solid foundation for modern eCommerce, facilitating trust among consumers who may otherwise be reluctant to complete purchases online. Keep in mind that EV certificates are the industry standard for modern eCommerce. SSL can also have a significant impact on search engine optimization (SEO), as search engines prioritize websites deemed secure.
What is a self-signed SSL certificate and should I use one?
Self-signed SSL certificates can be signed by entities, rather than obtained through trusted CAs. Although cost-effective, these are typically not recommended for public-facing websites due to their lack of external validation and potential for increased security risks.
What is SSL offloading?
SSL offloading strives to enhance server performance by handling the SSL encryption and decryption process on a dedicated hardware device, such as a load balancer. This can free up resources on the primary web server for other tasks. Furthermore, this can boost the scalability of web applications by reducing the processing load on the primary server.
What is SSL pinning?
SSL pinning, or certificate pinning, aims to prevent man-in-the-middle (MITM) attacks by ensuring that the client can only accept a specific, pre-defined SSL certificate or public key. This helps block unauthorized certificates from being used during secure connections.
While once widely used, SSL pinning has become largely obsolete due to its complexity, high risk of implementation errors, and lack of cryptographic agility. Misconfigurations can lead to application outages and costly fixes.
Secure your website with Sectigo SSL certificates
Protect your website and build trust with Sectigo SSL/TLS certificates. As a leading Certificate Authority, Sectigo offers solutions tailored to your needs, with multiple validation levels and options for securing single or multiple domains. Compare our certificates today or check out our resource library to learn more.