File used to create and update the flat-files used to store usernames and password for basic authentication of HTTP users; encrypts passwords using either a version of MD5 modified for Apache HTTP server, or the system's own crypt routine.

File names for HTPASSWD files start with a dot owing to the fact that most Unix-like operating systems consider any file with a name that begins with a dot to be a hidden file. HTPASSWD files are made up of rows with each row corresponding to a pair of username and hashed password separated with a colon in between.