Apache Reference: mod_digest, AuthDigestFile
Textual File for Message Digest-based User Authentication
Syntax: AuthDigestFile A
Example: AuthDigestFile etc/passwd.digest
Since: Apache 1.1
This directive specifies the textual file containing the
list of users and encoded passwords for MD5-based message digest
authentication. The filename argument consists of the absolute path
to the user file. It uses a special format that can be created
using the htdigest utility.