A security domain is a registry of PKI services. PKI services, such as CAs, register information about themselves in these domains so users of PKI services can find other services by inspecting the registry. The security domain service in Certificate System manages both the registration of PKI services for Certificate System subsystems and a set of shared trust policies.
The security domain manages the trust relationships between subsystems automatically, so if a TPS, TKS, and KRA are within the same security domain, they can communicate securely.
The security domain is used during subsystem configuration. When a subsystem is being set up, it can check the security domain registry to see available instances. If it needs to create a trusted relationship with another instance — like a TPS which uses a TKS and KRA for its operations — then the security domain is used to create a TPS agent user on the selected TKS and KRA instances.
The registry provides a complete view of all PKI services provided by the subsystems within that domain. Each Certificate System subsystem must be either a host or a member of a security domain.
Only a CA can host and manage a security domain. Each CA has its own LDAP entry, and the security domain is an organizational group underneath that CA entry:
Then there is a list of each subsystem type beneath the security domain organizational group, with a special object class (
pkiSecurityGroup) to identify the group type:
Each subsystem instance is then stored as a member of that group, with a special
pkiSubsystemobject class to identify the entry type:
dn: cn=server.example.com:8443,cn=KRAList,ou=Security Domain,dc=example,dc=com
SubsystemName: KRA server.example.com 8443