+use constant USER_REGEX => qr/^\w{2,20}$/pas;
+use constant PASSPHRASE_VERSION => 1;
+use constant INVALID_USER => "invalid-user\n";
+use constant BAD_PASSWORD => "bad-password\n";
+
+use if $ENV{MOD_PERL}, 'Apache2::RequestRec';
+use if $ENV{MOD_PERL}, 'Apache2::Access';
+use if $ENV{MOD_PERL}, 'Apache2::Const' => qw/OK HTTP_UNAUTHORIZED/;