In the digital age, cybersecurity has become an important issue that enterprises and individuals cannot ignore. SSL certificates provide a strong layer of protection for websites with their powerful encryption capabilities. The advent of multi-domain SSL server certificates (Subject Alternative Name, SAN certificates) in particular has brought great convenience to users managing multiple domains.

Overview of Multi-Domain SSL Server Certificates

SSL (Secure Sockets Layer) certificates are a standard security technology that establishes an encrypted link between a browser and a server, ensuring the privacy and integrity of all data transfers. Multi-domain SSL server certificates are a variation of this security protocol that allows users to protect multiple domains and subdomains with a single SSL certificate.

Traditional SSL certificates are typically tied to a single domain (for example, However, as businesses and organizations increasingly operate multiple websites, traditional SSL certificates are insufficient. Multi-domain SSL certificates were created to address this challenge, supporting encryption for 2 to 150 different domains under a single certificate.

The Issuers of Multi-Domain SSL Server Certificates and Their Working Mechanism

When applying, the issuing authority (CA) will consider the first domain as the primary domain, with other domains being treated as additional Subject Alternative Names (SAN). This means that when a browser establishes an SSL connection with a server, the SSL certificate will provide information for all included domains, and the browser will verify whether the current domain matches one of the entries in the certificate.

Steps to Obtain a Multi-Domain SSL Server Certificate

  1. Choose an issuing authority: Select a qualified and experienced digital certificate issuing authority (CA). This is critical as it directly relates to the reliability and recognition of the SSL certificate.
  2. Prepare verification information: There are three types of validation: Domain Validation (DV), Organization Validation (OV), and Extended Validation (EV). Depending on the selected type, businesses may need to provide different levels of identity verification information, such as organizational legal documents, proof of operational locations, etc.
  3. Submit an application: Submit an application to the CA and provide a list of all domains that need protection. The primary domain will serve as the basis for the certificate, with other domains added as SAN entries.
  4. Complete verification: The CA will carry out the necessary verification to ensure the accuracy of the application information. The verification process for DV certificates is relatively simple, while OV and EV certificates require more detailed organizational information verification.
  5. Deploy the certificate: Once verified and obtained, the certificate can be deployed on the server to provide SSL protection for all listed domains.

Advantages of Multi-Domain SSL Server Certificates

The greatest advantage lies in flexibility and cost-effectiveness. Enterprises can manage and protect all domains with just one certificate, which not only simplifies management work and reduces maintenance costs but also provides users with a unified and coherent security experience:

  • Cost-Effectiveness: Compared to purchasing individual SSL certificates for each domain, it can significantly reduce the operational costs of an enterprise.
  • Convenient Management: The workload for updating and managing certificates is significantly reduced, as only one certificate needs to be renewed and managed.
  • Compatibility: Multi-domain SSL server certificates are compatible with the vast majority of modern browsers and devices, eliminating concerns about technical compatibility issues.
  • Increased Trust: EV-type multi-domain SSL certificates display a green security lock in the browser’s address bar, increasing users’ trust in the website.