Authentication is the process of verifying the identity of a client. When access control, i.e. authorization, is enabled, MongoDB requires all clients to authenticate themselves in order to determine their access.
MongoDB supports a number of authentication mechanisms that clients can use to verify their identity. These mechanisms allow MongoDB to integrate into your existing authentication system.
MongoDB supports multiple authentication mechanisms.
Client and User Authentication Mechanisms
X.509 Certificate Authentication
MongoDB Challenge and Response (MONGODB-CR)
LDAP proxy authentication, and
Internal Authentication Mechanisms