SASL is a method for adding authentication support to connection-based protocols. To use SASL, a protocol includes a command for identifying and authenticating a user to a server and for optionally negotiating protection of subsequent protocol interactions. If its use is negotiated, a security layer is inserted between the protocol and the connection. This is the Cyrus SASL plugin that implements the LOGIN authentication mechanism. It's recommended that it only be used if absolutely necessary since it is not a secure authentication scheme.