How Do I Select an SSL Certificate?

This topic describes all you want to know about how to select an SSL certificate that meets your business needs.

For more details, see Differences Between Certificate Types

Which Certificate Type Is Suitable for Me?

When you purchase SSL certificates, you can select OV, OV Pro, EV, EV Pro, or DV (Basic) for Certificate Type.

EV certificates are recommended for finance and payment service businesses. For other enterprises, OV or higher-level certificates are recommended.
For use on mobile devices or in interface invocation, OV or higher-level certificates are recommended.
If you do not have a business license, you can apply for only basic DV certificates.

Which Certificate Authorities Are Available?

The following table lists the CAs supported by SCM and the certificate types each CA provides.

**Table 1** Certificate authorities
Certificate Authority	Description	SSL DV Certificates Supported	SSL OV Certificates Supported	SSL EV Certificates Supported
DigiCert	DigiCert, formerly Symantec, is the world's largest CA. It provides services for more than 100,000 customers in over 150 countries and regions. Advantages: High security, stability, and compatibility. Suitable for digital transactions with high security requirements and widely used by financial institutions.	Yes Single-domain certificates supported	Yes Single-domain, multiple-domain, and wildcard-domain certificates supported	Yes Single-domain and multi-domain certificates supported
GeoTrust	GeoTrust, the world's second largest CA, is an industry-leading provider of identity and trust validation. It is committed to offering the best service at the lowest price possible to enterprises of all sizes. Advantages: Powered by DigiCert. High security, stability, and compatibility, cost-effective, and less know-how required for HTTPS protection	Yes Single-domain and wildcard-domain certificates supported	Yes Single-domain and wildcard-domain certificates supported	Yes Single-domain and multi-domain certificates supported

Promotion activities

Single domain names (using domain name www.a.com and root domain name a.com as an example)
Figure 1 Promotion activities
Wildcard domain name (using domain names *.a.com and *.a.b.com as an example)
Figure 2 Promotion activities

Which Domain Type Should I Select?

You need to confirm the types of domain names you want to protect. In SCM, options for Domain Type can be Single domain, Multiple domains, or Wildcard.

**Table 2** Domain Type
Parameter	Description
Single domain	Single-domain certificates Only one common domain name can be associated. If you have only one domain name, select Single domain.
Multiple domains	Multi-domain certificate Multiple domains can be added to a certificate. Multiple single domains can be set for domains. For example, you can use one multi-domain certificate to protect domains example.com, example.cn, and test.com. You need to configure the domain quantity based on the number of domains you need to protect with a single multi-domain certificate. Different promotion activities are offered by CAs for subdomain names, or www domain names. For details, see Which Certificate Authorities Are Available? The following uses subdomain name www.a.com and root domain name a.com as an example to show the differences. For DigiCert and GeoTrust certificates, you can purchase a certificate for either the root domain or the subdomain to protect both domains at the same time. For example, if you plan to purchase a multi-domain certificate issued by DigiCert or GeoTrust and expect to use this certificate to protect www.a.com and a.com, just associate www.a.com or a.com with the certificate. The number of domain names ranges from 2 to 250. A maximum of 250 domain names can be protected with a certificate. If you have multiple domain names, select Multiple domains. Purchase domain names of the required quantity on the purchase page.
Wildcard	Wildcard-domain certificates Only one wildcard domain name can be associated. A wildcard domain name is the one that starts with a wildcard (), for example, .huaweicloud.com or .example.huaweicloud.com. Only the same-level domain matching is supported. For example, a certificate associated with .huaweicloud.com can protect p1.huaweicloud.com but not p2.p1.huaweicloud.com. If you need to protect p2.p1.huaweicloud.com, purchase a wildcard-domain certificate for .p1.huaweicloud.com. For details about more level matching rules, see Table 3. If your domain names are of the same level, you can select Wildcard* for Domain Type.

You can use one SSL certificate to protect more than one wildcard domain name and more than one common domain name. For details, see How Do I Apply for a Combination Certificate?

To purchase a wildcard-domain certificate, you need to pay attention to the domain name matching rules. Table 3 are some examples.

**Table 3** Examples of wildcard-domain matching rules
Domain name	Matched Domain Name	Unmatched Domain Name
*.huaweicloud.com	test.huaweicloud.com, yun.huaweicloud.com, example.huaweicloud.com, and other domain names	abc.test.huaweicloud.com, yun.test.huaweicloud.com, example.test.huaweicloud.com, and other domain names
*.test.huaweicloud.com	abc.test.huaweicloud.com, yun.test.huaweicloud.com, example.test.huaweicloud.com, and other domain names	abc.huaweicloud.com, yun.huaweicloud.com, example.huaweicloud.com, and other domain names

For wildcard-domain certificates, only those associated with root domain names support the domain names. For example:
- A certificate associated with the wildcard domain *.huaweicloud.com (a root domain) protects huaweicloud.com and other domain names of the same level. No additional certificate needs to be purchased for this.
- A certificate associated with the wildcard domain *.p1.huaweicloud.com (not a root domain) will not protect p1.huaweicloud.com (a different level domain). It can only protect domain names of the same level. To protect p1.huaweicloud.com, you would need to purchase a new certificate.
If the www subdomain is associated with a certificate, the certificate also protects the root domain. For example:
A certificate purchased for domain www.huaweicloud.com can also protect huaweicloud.com. There is no need to purchase another certificate.
Once your digital certificate is issued, the associated domain cannot be changed.

Table 4 provides domain type selection examples.

**Table 4** Domain type selection examples
Example Scenario	Example Domain Name	Domain Type Selection	Quantity Selected
You have only one domain.	huaweicloud.com	Single domain	Single-domain type. The value of Quantity is fixed at 1.
	test.huaweicloud.com	Single domain
	p1.test.huaweicloud.com	Single domain
You have multiple domains.	Two domains huaweicloud.com and p1.huawei.com	Multiple domains	2
	Three domains huaweicloud.com, p1.huawei.com, and p1.test.huaweicloud.cn	Multiple domains	3
	Four domains huaweicloud.com, test.huaweicloud.cn, p1.test.huaweicloud.cn, and p1.test.yun.huaweicloud.com	Multiple domains	4
You have multiple domains at the same level.	test.huaweicloud.com, yun.huaweicloud.com, example.huaweicloud.com, and other domain names are the same level and are part of *.huaweicloud.com.	Wildcard domain	Wildcard domain type. The value of Quantity is fixed at 1.