I don't know if it is strictly necessary, for me it works with these permissions:

700 (or drwx------) for the folder (folder2 in your case)
600 (or -rw-------) for the private_key file.

Both owned by the user that runs the tor process.

I don't know if it is strictly necessary, for me it works with these permissions:

700 (or drwx------) for the folder (folder2 in your case)
600 (or -rw-------) for the private_key file.

Both owned by the user and group that runs the tor process.