A requirement in almost any server application is a system for managing authentication . You need to be able to verify the identity of every user who attempts to access your server, based on their password or some other credentials. Once you allow a user to log in, you need to manage his permissions, controlling what he can and cannot do. The twisted.cred package is designed to facilitate these kinds of tasks.
Many parts of Twisted rely on twisted.cred, including the POP3, IMAP, SSH, and FTP servers. You can also use twisted.cred to add authentication to a web application, an SMTP server, a Perspective Broker server, or your own custom protocol. This chapter explains how twisted.cred works, and how to use it in your applications.
Building Simple Clients and Servers
Web Services and RPC
NNTP Clients and Servers
Services, Processes, and Logging