GNU SASL is an implementation of the Simple Authentication and Security Layer
framework and a few common SASL mechanisms. SASL is used by network servers
(e.g., IMAP, SMTP) to request authentication from clients, and in clients to
authenticate against servers.

GNU SASL contains a library (`libgsasl'), a command line utility (`gsasl') to
access the library from the shell, and a manual. The library includes support
for the SASL framework (with authentication functions and application data
privacy and integrity functions) and at least partial support for the CRAM-MD5,
EXTERNAL, GSSAPI, ANONYMOUS, PLAIN, SECURID, DIGEST-MD5, LOGIN, NTLM and
KERBEROS_V5 mechanisms.

The library is portable because it does not do network communication by itself,
but rather leaves it up to the calling application. The library is flexible
with regards to the authorization infrastructure used, as it utilizes callbacks
into the application to decide whether an user is authorized or not.

WWW: http://www.gnu.org/software/gsasl/