Looking for a solution for a site feature

Hey I am having trouble with a certain feature for a client as is described:

“We need to be able to upload shop drawings, specs and addendums when we get new jobs and be able to update it as we close and open new ones. He wants that to be secured by a password and each job different password so we can give it out to the contractors we want to give information to”

If anyone knows of a plugin or any tips that would be great!