What is Wildcard Certificate?
A wildcard certificate is issued to a domain and all its subdomains. It is a digital certificate and an ideal and cost-efficient choice for an entity with multiple pages or sites existing on one single domain. Users just make one single payment for all the domains and any future pages that they may be adding.
The wildcard certificate contrasts with the standard SSL certificate that is issued to a one domain name. A wildcard certificate consists of a period(.) and an asterisk (*). The certificate comes with a common name of * yourdomain.com and a SAN (Subject Alternative Name) of yourdomain.com and protects all other subdomains like payment.domain.com, sales.domain.com, mail.domain.com etc.
Applying a single certificate to subdomains can work to be a money and time- saving effort. Since it is scalable, users need not purchase a new certificate each time they add new subdomains.
The only drawback here is that for some reason if it is revoked in one subdomain, the certificate stands cancelled on all the subdomains. In the same manner, in case it is hacked on one subdomain, risks of other subdomains being affected too are plenty.
There are still many other types of certificates that may suit the small businesses.