volmar

This plugin puts a global password selected by you on all posts. Based on Matt Mullenwegs plugin “Protect old posts”
I’ve looked for a plugin like this but couldn’t find one that fitted my needs so i this one. I hope it will be helpfull for someone else to.
BEWARE: This will write over all old passwords and replace it with the one you select.

Password Protect All Posts

This plugin puts a global password selected by you on all posts. Based on Matt Mullenwegs plugin "Protect old posts"

profaceoff

“Protect Pages & Posts” plugin protects your WordPress pages and posts on demand.
Your WordPress website may have some private pages and posts that you only want certain people to see them. “Protect Pages & Posts” plugin helps you just that. It is designed to protect both your WordPress pages and posts. In other words, your private content is no longer accessible by other people until you share its private URLs with them.
PROTECT WORDPRESS PAGES & POSTS
Our plugin protects your WordPress pages and posts. Once protected, they cannot be accessed directly by their original URLs. If people attempt to access this private content directly via its original URLs, they will be redirected to your 404 error page.
AUTO-GENERATE PRIVATE URLS
Our plugin will automatically generate a Private URL containing random strings for you to see that content. This private URL is the ONLY way to access the protected content. 
You can get that private URL to clipboard and subsequently paste it on your browsers or email by <a href="https://www.buildwps.com/documentation/protect-wordpress-pages-posts/?utm_source=wp.org&utm_medium=plugin-repo&utm_campaign=under-private-urls" rel="nofollow ugc">clicking on the Copy URL button</a>.
BLOCK GOOGLE FROM INDEXING YOUR PAGES & POSTS
“Protect Pages & Posts” plugin explicitly tells Google and other search engines <a href="https://www.buildwps.com/documentation/protect-wordpress-pages-posts/?utm_source=wp.org&utm_medium=plugin-repo&utm_campaign=under-index-google" rel="nofollow ugc">not to index</a> any of your protected content so that your pages and posts and original URLs will never appear on the search results.

Protect Pages & Posts

Protects content of your WordPress pages and posts.

Password Protect All Posts vs Protect Pages & Posts