SSL/TLS Certificate Types and Purposes

SSL certificates are used to secure communications between a website, host or server, and end users that are connecting to that server. An SSL certificate confirms the identity of the domain name that is operating the web site, encrypts all information between the server and the visitor and ensures the integrity of the transmitted information.

There are several types of SSL certificates that we can issue using the InCommon certificate service.  A brief description of the types of SSL certificates offered, their typical purpose, and limitations follows:

Certificate Type

Description and Purpose

Available Validity

Typical Processing Time

Single domain (Incommon SSL Certificate)

An SSL certificate protects a single domain e.g.  These are the "traditional" SSL certificates that have been in use since the advent of the SSL protocol.

1 year

5 minutes

Multiple domain (Incommon Multi-domain SSL certificate)

A multiple domain certificate allows you protect multiple host names with a single SSL certificate.  These are also known as SAN (Subject Alternative Name) certificates.   Up to 100 domain names can be included in a multi-domain certificate. However, if applying for a certificate with more than 20 SANs, please contact so that we can assist you in this request. 

These certificates are often used on a single servers hosting many web sites to eliminate the need to use unique ip addresses for each web site e.g. and

1 year

5 minutes

Wildcard (Incommon wildcard SSL certificate)

A wildcard certificate protects a domain and unlimited subdomains of that domain e.g * secures,, etc.  Because of the increased risk of using wildcard certificates, we require an the requestor agree to certain terms of service and suggest using multi-domain certificates rather than wildcard certificates when possible.

1 year

5 minutes

IGTF Certain academic grid computing requires these Interoperable Global Trust Federation certificates. 
1 year   5 minutes
Code Signing In rare instances, certain types of desktop software may benefit from having signed code. 3 years  2-3 Business days

Keywordsserver certificates ssl tls incommon comodo sectigo   Doc ID18922
OwnerJake S.GroupSSL Server Certificates
Created2011-06-19 19:00:00Updated2024-06-12 08:08:26
SitesDoIT Help Desk, SSL Server Certificates
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