The Password Protect plugin enables users to secure their Obsidian notes and folders by setting a password, ensuring that sensitive content like journals remains hidden. Hidden notes are not visible in search results or graph view until the correct password is entered. The plugin works by changing file extensions to hide them, offering a layer of protection against casual viewers. While the files are not encrypted, they are inaccessible without the password. The plugin also allows for syncing hidden files across devices using services like Syncthing, provided certain conditions are met. It provides basic protection and is ideal for users looking for privacy within their Obsidian vault.