Beginner’s Guide to TLS SSL Certificates
An SSL certificate is a digital certificate that authenticates a website’s identity and enables an encrypted connection. SSL stands for Secure Sockets Layer, which is a security technology that establishes an encrypted link between a web server and a web browser. This allows sensitive information like login credentials, payment info, etc. to be transmitted securely.
SSL certificates are issued by certificate authorities (CAs), which are trusted third parties that verify the certificate owner’s identity. Once issued, the certificate is installed on the web server that hosts the website. When visitors connect to the website, the browser will check that the website’s SSL certificate is valid and that it is issued by a trusted CA. The website can then use the certificate to initiate an encrypted session with the browser.
How SSL Certificates Work
An SSL certificate enables a secure connection between a web server and browser through a protocol called Transport Layer Security (TLS).
Here is how it works:
- A user requests access to a website secured with SSL.
- The web server sends its SSL certificate to the browser. This certificate contains the domain name, server address, root CA signature, and public key.
- The browser checks the certificate is valid and issued by a trusted certificate authority (CA). It also verifies the domain name matches the website.
- If valid, the browser creates an encrypted session with the server using the public key from the certificate.
- The browser and server encrypt and decrypt data using public-private key encryption during the secure session.
- The padlock icon shows the user their connection to the website is secure and encrypted.
By implementing an SSL certificate on a website, visitors can verify the site’s legitimacy and browse safely. Their sensitive information remains protected from cybercriminals as it travels across the internet encrypted.
Types of SSL Certificates
There are different types of SSL certificates available depending on the level of validation and security required:
Domain Validated SSL Certificate
A Domain Validated (DV) SSL certificate validates ownership of a domain name only. It is issued within minutes and offers basic 256-bit encryption. DV SSL certificates are affordable and ideal for blogs and informational websites.
Organization Validated SSL Certificate
An Organization Validated (OV) SSL certificate provides enhanced validation. The Certificate Authority verifies the company’s legal and physical existence plus ownership of the domain. OV SSL certificates activate the browser padlock and display organization details to users. They provide strong 256-bit encryption.
Extended Validation SSL Certificate
Extended Validation (EV) SSL is the highest-level certificate. It requires thorough verification of an organization’s legal, operational, and physical existence. EV SSL certificates present the green browser bar and company name for a clear visual trust signal. They use industry-leading 2048-bit encryption.
Wildcard SSL Certificate
A Wildcard SSL certificate secures unlimited subdomains on a single certificate. It validates domain ownership and allows you to efficiently secure a main domain and multiple subdomains for a low cost. Wildcards support 256-bit encryption and are ideal for large websites.
Multi-Domain SSL Certificate
Also called Unified Communications Certificates, Multi-Domain SSL certificate protects multiple domains and subdomains under one certificate. It provides the same validation level across all domains and simplifies SSL management for multiple domains and servers.
Benefits of SSL Certificate
Why is SSL Important?
There are three core reasons why every website should use SSL certificates in 2023:
1. Encrypt Sensitive Data
SSL encrypts all communications between a browser and web server. This means any sensitive data customers exchange with your website (such as login details, personal information, and credit card numbers) remains protected from cybercriminals. SSL is essential for secure transactions.
2. Comply with Regulations
Various compliance standards like PCI DSS require the use of SSL to protect online transactions. SSL ensures companies securely manage customer data and comply with industry regulations.
3. Ranking Boost
Google ranks websites using HTTPS encryption higher than those without SSL. The search giant sees secure sites as more legitimate and trustworthy. Implementing SSL improves website SEO and visibility in search engines.
4. Provide Trust & Confidence
The browser padlock and green address bar signals a website is secure. This provides visitors with more confidence to use the site and make purchases. SSL certificates establish trust and credibility for your brand.
5. Prevent Browser Warnings
Web browsers like Chrome now display warnings on sites without HTTPS to prompt users they are insecure. SSL eliminates these errors and security alerts that scare visitors away from your site.
How to Get an SSL Certificate
Follow these five steps to implement SSL on your website:
1. Choose a Certificate Type
Consider your website structure, validation needs and budget to select the right SSL certificate type – DV, OV, EV, Wildcard or Multi-Domain.
2. Purchase from a Trusted CA
Only buy SSL certificates from reputable certificate authorities like DigiCert, RapidSSL, Thawte, Comodo, GlobalSign and GoDaddy. This ensures your certificate aligns with browser and OS trust requirements.
3. Generate a CSR Code
Create a certificate signing request (CSR) file on your web server. This verifies you own the domain and contains your public key required to generate the SSL certificate.
4. Install the SSL Certificate
Once issued, install the new SSL certificate on your web server. You may need to restart your server for the new certificate to take effect.
5. Redirect Site to HTTPS
Finally, redirect all HTTP website requests to HTTPS using .htaccess rules or URL redirects. This ensures all site visitors connect securely via HTTPS moving forward.
You can purchase and install SSL certificates directly through your hosting provider or domain name registrar for added convenience.
SSL Certificate Authorities
SSL certificates must be issued and digitally signed by a trusted certificate authority (CA) for proper browser validation. Here are some of the largest CAs:
- DigiCert: The world’s leading SSL provider trusted by many Fortune 500 companies. DigiCert offers rapid issuance times and top-notch customer support.
- RapidSSL: A budget-friendly CA providing domain validated certificates starting under $10 per year. Owned by DigiCert.
- Thawte: Founded in 1995, Thawte is one of the longest-standing SSL authorities. It provides OV and EV certs with strong 256-bit encryption.
- Comodo: As an established CA, Comodo supplies extensive SSL and cybersecurity solutions for businesses. Prices start around $30 per year.
- GlobalSign: A major international CA offering basic encryption DV certs to extensive validation EV certs for ecommerce sites.
- GoDaddy: The world’s largest domain registrar also provides competitively priced SSL certificates to its hosting customers.
- Let’s Encrypt: A non-profit CA that provides free domain validated certificates. It’s integrated into many website platforms and services.
These trusted CAs undergo rigorous auditing to adhere to industry standards for SSL certificate issuance. Choosing a reputable provider ensures your website visitors see the SSL as valid and secure.
SSL Certificate Errors & Warnings
It’s critical to properly install and maintain your SSL certificate to avoid browser errors or warnings:
- Untrusted Root Certificate: The certificate is not issued by a recognized certificate authority browser’s trust. Often self-signed certificates trigger this.
- Certificate Chain Errors: Indicates missing intermediate certificates in the SSL certificate chain of trust. Easy to fix by installing the intermediate certificate.
- Expired Certificate: Browsers display warnings when an SSL certificate has expired, and the site is no longer trusted. Renew certificates annually to avoid this.
- Domain Mismatch: When the domain name on the certificate doesn’t match what the user entered in the browser. Caused by an improper SSL certificate installation.
- Insecure SSL Protocol: Warnings will appear if your server uses outdated SSL protocols. Upgrade to the latest TLS 1.2 or TLS 1.3 protocol to resolve.
Properly installing SSL certificates and keeping them renewed will minimize browser errors. Monitor for warnings and address any issues immediately.
Improving Website Security Further
While SSL certificates provide essential encryption and validation, additional measures further strengthen your website security:
- Use HTTP Strict Transport Security (HSTS): The HSTS policy forces browsers to only communicate over HTTPS, preventing man-in-the-middle attacks. It converts HTTP links to HTTPS and is enabled by adding a Strict-Transport-Security header.
- Enable HTTP Public Key Pinning (HPKP): With HPKP, a header tells browsers to associate a specific cryptographic public key with your domain for a period of time. This prevents MITM attacks even if a CA is compromised by “pinning” keys.
- Add a Content Security Policy (CSP): A CSP whitelist dictates the sources browser can load resources from. This thwarts XSS attacks and data injection by only allowing approved content sources, scripts, stylesheets, etc.
- Monitor for Malware & Vulnerabilities: A web application firewall (WAF) inspects HTTP traffic to block SQL injections, XSS attacks, and other threats. Vulnerability scanners probe sites for outdated software, misconfigurations, and other vulnerabilities.
- Enable CORS Properly: Cross-Origin Resource Sharing (CORS) prevents unauthorized cross-domain requests. If configured incorrectly, CORS could expose your site to attacks.
- Practice Least Privilege Access: Only give users minimal access permissions needed to do their jobs. This limits damage if credentials are compromised.
- Perform Penetration Testing: Ethical hackers test your systems and security controls by safely attempting real cyber-attacks. Pen testing identifies vulnerabilities before criminals do.
- Install DDoS Protection: Volumetric DDoS attacks can take down websites by overloading servers with bogus traffic. Implement a DDoS mitigation service.
- Secure Servers & Backups: Harden web servers, encrypt data backups, install firewalls, use containerization, and take other steps to tighten infrastructure security.
Common SSL Certificate File Formats
SSL certificates come in different file formats depending on the web server or application used:
- .pem: A PEM file contains the SSL certificate and any intermediate certificates and private key in Base64 encoded plain text. PEM is a common format across many systems.
- .crt: The .crt file only includes the SSL certificate. This contains the public key and domain name but not the private key.
- .cer: A .cer file is the same as a .crt file. It is possible to convert crt to pem file format.
- .der: The DER format contains certificate and public key in binary form rather than plaintext like PEM. Not as widely compatible.
- .pfx: The .pfx or .p12 file is exported encrypted with a password. It includes the SSL certificate, any intermediates, and the private key combined.
- .p7b: The .p7b file format contains the SSL certificate with any intermediate certificates but without the private key.
Most web servers and services want the SSL certificate and private key together in PEM format. The specific file extension (.pem, .crt, .cer) does not matter as much as the file contents.
Lifecycle of SSL Certificate Validation Explained
When you request an SSL certificate, it goes through a lifecycle of validation before being trusted:
- First, you provide your private and public keys along with details like domain name to the Certificate Authority when requesting the cert.
- The CA then checks to confirm you control the domain and that the domain exists and is not fraudulent. This is “domain validation.”
- For OV or EV validation, the CA also verifies your organization’s legal, operational and physical existence.
- The CA signs your certificate, making it valid using their Certificate Signing Request (CSR).
- Your signed certificate is provided to you for installation on your web server.
- When a user visits your site, the browser checks the issuing CA is valid and trusted. The browser also verifies the certificate signature, expiration, domain, etc.
- If all validation checks pass, the website is trusted, and the user sees the secure padlock icon.
The rigorous validation process provides assurance for browsers and users that the SSL certificate was properly issued and verified.
Conclusion
SSL certificates are essential for any business with an online presence. By encrypting sensitive communications, establishing trust, and securing your website, SSL protects your customers and your reputation. With rising cybercrime threats, the costs of SSL certificates are minor compared to the risks of leaving your site insecure. While the validation process seems complex, reputable certificate authorities make obtaining SSL straightforward.
Given how vital website security is in today’s digital world, SSL certificates provide necessary protection and confidence for customers to safely engage with their business online. Implementing the right SSL solution demonstrates your commitment to security and enables safe, compliant online operations.
Frequently Asked Questions (FAQ) on What is SSL Certificate
What does SSL stand for?
SSL stands for Secure Sockets Layer. It is the standard protocol for encrypting and securing data sent between a browser and web server.
Do SSL certificates expire?
Yes, SSL certificates expire after 1 or 2 years typically. They must be renewed regularly to maintain security and avoid browser warnings.
What’s the difference between SSL and TLS?
SSL refers to Secure Sockets Layer, while TLS is the newer Transport Layer Security protocol. The terms are often still used interchangeably.
Is SSL free?
Basic domain validated (DV) SSL certificates are available for free or very low cost from some certificate authorities. Higher security OV and EV certificates require more validation and cost more.
Can I use SSL with a shared hosting account?
Yes, most shared hosting providers make it easy to add an SSL certificate on websites for additional security.
How long does it take to get an SSL certificate?
You can obtain low-cost domain validated SSL certificates instantly or within minutes or hours. Higher validation OV and EV certificates take 1-5 days on average.
What are the different SSL certificate validation levels?
The three main validation levels are domain validation (DV), organization validation (OV), and extended validation (EV). DV only confirms domain ownership, while OV and EV verify organization identity.
Priya Mervana
Verified Web Security Experts
Priya Mervana is working at SSLInsights.com as a web security expert with over 10 years of experience writing about encryption, SSL certificates, and online privacy. She aims to make complex security topics easily understandable for everyday internet users.
