LDAP has its roots in logical directory models dating back over 30 years—conceptually akin to a combination of an organizational chart and an address book. Today, LDAP is used more and more as a way to centralize corporate user information, partition thousands of users into logical groups, and allow unified sharing of user information between many disparate systems.
For security purposes, LDAP is quite commonly used to facilitate centralized username and password authentication—users' credentials are stored in the LDAP directory, and authentication requests can be made against the directory on the user's behalf. This eases management for administrators, as user credentials—login ID, password, and other details—are stored in a single location in the LDAP directory. Additionally, organizational information, such as group or...