If you want to protect all posts within selected post type (for example all products), you can try my Bulk Password Protect Post Types plugin. I published this plugin few days ago and it allows you to choose one or more post types and set password for all posts within.
If you like it, feel free to rate it on WordPress.org or share. If you have a suggestion on how it can be improved, I’d appreciate if you could do that.
Post How to password protect all posts within post type je prvi puta viđen na bbird.me.