Apache Reference: mod_auth
mod_auth - User Authentication by User Name/Password
Since Apache 1.0, src/modules/standard/mod_auth.c
Rob McCool, Robert S. Thau, Dirk van Gulik (1995)
The authentication module mod_auth deals with the HTTP Basic Authentication facility, which is simply a user name/password pair submitted by the client together with the request for a document. This module allows one to check this information against a flat-file database similar to UNIX's C and C files and to deny access when the given user name/password doesn't match the database information. Special variants of this module exist that offer the same functionality but use a database from other than a flat-file (for performance reasons).
AuthAuthoritative AuthGroupFile AuthUserFile