What is an SSL certificate? How do you apply for and configure an SSL certificate for your website to enable HTTPS encryption?

What is an SSL certificate?

An SSL certificate, whose full name is Secure Sockets Layer Certificate, has now evolved into its successor, the TLS (Transport Layer Security) protocol. However, the industry still commonly refers to it as an SSL certificate. It is a type of digital certificate whose primary function is to establish an encrypted and secure communication channel between the client (such as a user's browser) and the server (such as your website server).

You can think of it as a combination of a digital identity card and an encrypted lock. When a user visits a website that has an SSL certificate (the URL usually starts with “https://” and is accompanied by a lock icon in the browser’s address bar), the certificate performs two crucial functions: First, it verifies the user’s identity, proving to the visitor that “this is indeed the website you are trying to access, and not a malicious imitator.” Second, it encrypts the data being transmitted between the user and the website. This ensures that all information exchanged, such as login credentials, credit card details, and personal privacy, is securely encrypted. Even if it were intercepted by a third party, the data would be impossible to decipher.

The Core Types of SSL Certificates and How to Choose One

Not all SSL certificates are the same; they are mainly classified into the following three types based on the level of verification and the scenarios they are suitable for. Choosing the right certificate for your needs is the first and most important step.

Recommended Reading The Ultimate SSL Certificate Guide: From Beginner to Expert – Comprehensive Protection for Website Data Security。

Domain Validation Certificate

DV (Domain Validation) certificates are the type of certificate with the lowest level of verification, the fastest issuance process (usually within a few minutes to a few hours), and the lowest cost. The certificate authority only verifies the applicant's ownership of the domain name (for example, by sending a verification email to the email address registered for that domain or requiring the setting of specific DNS records). They provide only basic encryption capabilities and are suitable for personal websites, blogs, or testing environments. These certificates do not display the company name; in browsers, they typically only show a lock icon.

Bluehost SSL Certificate

BlueHost SSL Certificates offer 1-2 year extension options, support for RSA or ECC algorithms, key lengths up to 4096 bits, and up to $1.75 million in protection.

From $7.49 USD per month

Access to Bluehost SSL Certificates →

hosting.com SSL Certificate

Affordable DV, OV, EV SSL certificates, up to 256-bit encryption, 5 ~ 1 million USD protection amount, 24/7 support

From $2.5 USD per month

Visit hosting.com SSL Certificates →

Organizational validation type certificate

OV certificates offer a higher level of credibility than DV certificates. In addition to verifying the ownership of the domain name, the certificate issuing authority also checks the real identity of the applicant (such as the company name, address, phone number, etc.). This information is embedded in the certificate details, and users can view it by clicking on the lock icon in their browser. OV certificates are suitable for commercial websites and corporate portals, providing users with a clearer indication of the identity of the website owner and thus enhancing their trust in the website.

Extended Validation Certificate

EV certificates are the most rigorously verified and highest-security certificates. The application process is extremely thorough, requiring a comprehensive offline review of the organization. Once an EV certificate is deployed, the most noticeable feature is that the address bar in advanced browsers (such as Chrome and Edge) will not only display a lock icon but also the verified, green name of the enterprise directly in the address bar. This provides the highest level of visual security for websites that have extremely high trust requirements, such as financial institutions and e-commerce platforms.

How to apply for an SSL certificate?

The process of applying for an SSL certificate is relatively standardized. Regardless of the type of certificate chosen, the basic steps follow the same procedure.

Step 1: Generate a certificate signing request

Before purchasing a certificate, you need to generate a CSR (Certificate Signing Request) file on your website server. This process is typically carried out through the server management panel (such as cPanel or Plesk) or via the command line (using OpenSSL tools). When generating the CSR, you must provide accurate information related to your organization or domain name; in particular, the “Common Name” field must include the full domain name that you want to secure with the certificate. The system will then generate a pair of asymmetric keys: a private key (which must be kept absolutely confidential and stored on the server) and a public key (which is included in the CSR file).

Recommended Reading Understanding SSL Certificates in One Article: A Comprehensive Guide from Principles to Application and Installation。

Step 2: Select and purchase the certificate

Based on the type of your website and your security requirements, select a suitable certificate authority (CA) to issue the certificates. You can choose well-known international CAs such as DigiCert, Sectigo, or GlobalSign, or you can opt for services that offer free DV (Domain Validation) certificates. Submit the CSR (Certificate Signing Request) file and complete the purchase process. For OV (Organizational Validation) and EV (Extended Validation) certificates, the CA will subsequently initiate the organization validation process, which may require you to provide documents such as your business license.

Step 3: Complete the verification process and obtain the certificate.

The CA (Certificate Authority) will perform verification based on the type of certificate you have applied for. For DV (Domain Validation) certificates, the verification process is usually automated. Once the verification is complete, the CA will send you the issued SSL certificate file (typically a.crt or.pem file, which may include an intermediate certificate chain) via email or provide a download link.

How to configure an SSL certificate to enable HTTPS?

After obtaining the certificate file, the next step is to install and configure it on your server, and to enable HTTPS access by default.

UltaHost SSL Certificate

DV, EV, OV certificates, up to $1,750,000 USD coverage, unlimited sub-domains, iOS and Android apps, discounted 20% per month, $15.95 USD onwards, 30-day money-back guarantee

Visit UltaHost

Install the certificate on the server.

Log in to your website server and upload the certificate file issued by the CA (as well as the intermediate certificate file) and the previously generated private key file to the specified directory. The installation method varies depending on the server software. For example, on an Apache server, you will need to make modifications to the configuration files.httpd.confor the site'sssl.confThe document specifiesSSLCertificateFileThe path to the certificate file andSSLCertificateKeyFile(The path to the private key file.) On an Nginx server, this information needs to be included in the site configuration file.serverWithin the block, make the modification.ssl_certificateandssl_certificate_keyThe command points to the correct file path. After the configuration is completed, restart the web server to apply the changes.

Configure forced HTTPS redirection

After installing the certificate, your website will be able to use it for secure communication.https://Access is available. However, to ensure that all traffic is encrypted and to prevent users from misusing the service,http://For access, a forced redirect must be configured. This can be achieved by modifying the server configuration file. In Nginx, you can add the necessary settings within the server block that listens on port 80. return 301 https://$host$request_uri; Rules: In Apache, these can be defined in the root directory of the website..htaccessAdd a rewrite rule to the file to redirect all HTTP requests to HTTPS.

Verify the configuration and perform subsequent maintenance.

After completing the configuration, visit your website using a browser and ensure that a lock icon appears in the address bar and that there are no security warnings. You can use online tools (such as SSL Labs’ SSL Server Test) for a thorough inspection to verify whether the certificate has been installed correctly and whether the encryption suite is secure. SSL certificates have an expiration date (usually one year), so make sure to renew and re-install the certificate before it expires to prevent security warnings and access issues due to an expired certificate.

Recommended Reading The Ultimate Guide to SSL Certificates in 2026: From Beginner to Expert, Ensuring Website Security。

summarize

SSL certificates are the foundation for implementing HTTPS encryption on websites. They establish a bridge of trust and security between users and servers through both authentication and data encryption. Understanding the differences between DV (Domain Validation), OV (Organization Validation), and EV (Extended Validation) certificates, as well as the entire process of generating a CSR (Certificate Signing Request), submitting the application, undergoing verification, and finally installing the certificate on the server and configuring mandatory HTTPS redirection, are all essential steps in creating a secure network environment. For any website owner, deploying SSL certificates is no longer an optional feature; it has become a necessary measure to protect user data, enhance website credibility, and meet the requirements of search engine rankings.

FAQ Frequently Asked Questions

What is the essential difference between free SSL certificates and paid ones?

免费证书（如Let's Encrypt颁发的）通常属于DV类型，仅提供基础的加密功能，有效期较短（多为90天），需要频繁自动续期。它们不提供组织身份信息验证，且通常不包含商业保险。

Paid certificates offer a wider range of options, including OV (Organizational Validation) and EV (Extended Validation) certificates, which provide rigorous organization-level verification and display more visible trust indicators in browsers (such as a green address bar). Paid certificates typically come with a longer validity period, professional technical support services, and financial compensation insurance in case of data breaches caused by certificate-related issues.

Does my website, which is just a personal blog, also need an SSL certificate?

Yes, it is highly recommended to deploy HTTPS. Firstly, major search engines like Google have explicitly stated that HTTPS is a positive factor in search rankings. Secondly, modern browsers (such as Chrome) mark all HTTP websites as “insecure,” which can significantly affect visitors’ trust in the website. Lastly, even if no sensitive transactions are conducted, it is still necessary to protect visitors’ browsing privacy (such as their browsing history) and prevent content from being hijacked or tampered with. Free DV certificates are more than sufficient to meet the needs of personal blogs.

Will the website loading speed slow down after configuring the SSL certificate?

In the early days, the computational overhead associated with the SSL/TLS handshake process could cause minor delays. However, with the improvement of hardware performance and the widespread adoption of the TLS 1.3 protocol, these performance issues have become virtually non-existent. TLS 1.3 has significantly reduced the time required to establish a secure connection by simplifying the handshake process.

In fact, enabling HTTPS also activates the HTTP/2 protocol. HTTP/2 utilizes features such as multiplexing and header compression to significantly improve the loading speed of websites, which can more than compensate for the minor overhead associated with encryption.

Why does the browser still display a security warning after the certificate has been installed?

This is usually caused by several common reasons. The first one is the “mixed content” issue: on your HTTPS page, certain elements are loaded from non-HTTPS sources, which can lead to security vulnerabilities.http://The protocol has loaded resources such as images, scripts, and style sheets. As a result, the browser will consider the entire page to be insecure. It is necessary to change all the reference links to these resources.https://Or use a relative protocol.//。

Second, the certificate does not match the domain name; in other words, the domain name you are accessing is not listed in the certificate’s “Common Name” or “Subject Alternative Name” fields. Third, the certificate chain is incomplete—the server has not correctly configured the intermediate certificates, which prevents the browser from establishing a complete trust chain. Using an SSL testing tool can help you accurately identify the issue.