Show Related Articles Based On Keywords

Hello, I hope someone can help me out, been searching for a few days now and have found tons of related article threads but none that answer my question.

I need a plugin that allows me to enter keywords for each post and then displays posts (older & newer) that have the same keywords. I want to enter the keywords manually and I want the plugin to create the links automatically.

If the plugin shows X# of posts then a link (ex. see all related) that can take you to a page with a list of all related posts would be great. Also if the plugin could rank the related articles and order them based on how many keywords they have in common with the original article that would be even better but not needed (ex. Very related, Somewhat related). Finally, I do not want the keywords to actually be shown anywhere on the page.

If anyone has any suggestions on a plugin like this please let me know.

Thank you.