In several companies across the world, Windows servers are the integral constituent of IT infrastructures. These companies, if required, set up a Public Key Infrastructure (PKI) for issuing digital certificates for their network. PKIs implement and manage certificates, which can be deployed for device authentication, securing web servers (SSL), encrypting emails (S/MIME), digital signatures for documents, and many more similar activities.
Yet, you’d be surprised to learn that many people are unaware that the two can be connected. This is where AD CS comes into the picture.
Active Directory Certificate Services (AD CS) is a Microsoft product for an on-premise PKI solution. It has been in existence for some time and provides digital certificates, public key cryptography, and digital signature capabilities for the organization.
However, if you have dabbled with PKI in the past, you would know that AD CS is not needed to build a CA. It is not needed for signature certificates or several other use cases readily available on the net.
So, why should you bother yourself with AD CS?
The clue here is “provisioning.” You know that it is simple to create your own CA or sign a few certificates with tools like OpenSSL. You can also buy a few certificates and install them manually, but what do you do when these same activities are needed to be done on a large scale?
AD CS permits your organization to distribute certificates from a CA at an extensive level, where the company employs thousands of employees and possibly uses even more machines.
How does AD CS do that?
Active Directory is a Windows domain network directory service. Hence, the foundation for each Active Directory deployment is Active Directory Domain Services (AD DS). It stores information about computers, groups, and users within a domain and also verifies their credentials, and sets the access rights. Learn more on ‘What is a Forest in Active Directory‘
Similar to how HR maintains all relevant information of employees in an organization, AD DS maintains information of the members of the domain. AD DS being the primary directory, information that is registered to this inventory may be attached by other Active Directory services, like AD CS.