KaeruCT

This plugin allows passwords for password-protected pages/posts to be passed directly through the URL.
The query string parameter that should contain the password is <code>pw</code>.
For example, if the URL of your post is <code>http://myblog.com/password-protected-page/</code> and the password is <code>PASSWORD</code>, 
then just append <code>?pw=PASSWORD</code> to it.
If the URL already contains a query string (for example, <code>http://myblog.com/?p=5</code>), then be sure to append <code>&pw=PASSWORD</code> instead.

Password Passthrough

This plugin allows passwords for password-protected pages/posts to be passed directly through the URL.

peckjon

WordPress allows editors to mark Posts as “Protected” or “Private”.
In some Themes, the words “Protected:” or “Private:” are automatically placed before the title of each post.
This plugin removes those words from the titles.

Clean Protected and Private Page Titles

Some themes prefix post titles with "Protected" or "Private"; this plugin removes those prefixes

Password Passthrough vs Clean Protected and Private Page Titles