| External authentication | The process by which a client is identified and authenticated by something other than an Oracle username and password. For example, a user can be authenticated by the operating system or by a network authentication service such as Cybersafe Challenger or Kerberos. |
| Operating-system authorized login or OPS$ login | A term formerly used to refer to the process by which a user's identity is authenticated by the operating system (same as operating system authentication). The client passes its operating system user name to the server. The server then verifies that the user has an operating-system account by calling the operating system. |
| Proxy logins | Used by the server to impersonate the client in performing an operation for the client. Proxy logins are performed for database links, or server-to-server connections. Data is only as secure as the underlying protocol can provide. Security will vary depending on the underlying protocol in use, and network topology. |
| Privileges and roles | They control the access a user has to database functions and the schema objects within the database. |
For more information, see 
