There are many different types of SSL certificates based on the number of domain names or sub-domains owned, such as :
Single - secures one fully-qualified domain name or sub-domain name/
Wildcard - covers one domain name and an unlimited number of its sub-domains.
Multi-Domain - secures multiple domain names
and the level of validation needed, such as :
Domain Validation (DV) – this level is the least expensive and covers basic encryption and verification of the ownership of the domain name registration. This type of certificate usually takes a few minutes to several hours to receive.
Organization Validation (OV) – in addition to basic encryption and verification of ownership of the domain name registration, certain details of the owner (e.g., name and address) are authenticated. This type of certificate usually takes a few hours to several days to receive.
Extended Validation (EV) – this provides the highest degree of security because of the thorough examination that is conducted before this certificate is issued (and as strictly specified in guidelines set by the SSL certification industry’s governing consortium). In addition to ownership of the domain name registration and entity authentication, the legal, physical and operational existence of the entity is verified. This type of certificate usually takes a few days to several weeks to receive.