File permission in *nix

To access child directory, the parent directory at least set to be executable.
For example:

/home/user1 ---- set to 7 - -
/home/user1/public_html ---- set to 7 5 5

In order to let other user access public_html of user1, permission of /home/user1 must be changed to 711 at least.

Note: setting a folder’s permission to 711, other user cannot read this folder (list the folder to see what files inside), but the readable file in that folder can be reached if other user knows file’s name.