Permissions and passwords are different
Folder permissions control which local accounts may read or modify an item. An administrator or software running with enough access may still change those permissions. Encryption transforms stored data so it cannot be read without the key.
The Mac alternative: an encrypted disk image
An encrypted sparsebundle appears as a package while locked. After you enter its passphrase, macOS mounts it as a volume that Finder can browse like a folder. Unmounting it closes access again.
Why sparsebundles are useful
A sparsebundle grows as content is added, up to its configured capacity, instead of reserving the entire maximum size immediately. It is still a package made of many band files, so copy or synchronize it only while it is unmounted.
What Finder still does
Finder remains the place where you open, edit, organize, and search mounted content. The encryption boundary is the mounted volume, not each individual file.
A practical Finder workflow
- Create a local encrypted vault from the folder you want to protect.
- Unlock the vault and open its mounted location in Finder.
- Work normally, then close any documents, previews, or terminals using the volume.
- Relock the vault to unmount it and close access.
Limits to remember
Finder permissions alone are not encryption. An unlocked vault is available to the active Mac session, and a forgotten passphrase cannot be recovered. Keep backups, use FileVault for whole-disk protection, and avoid active sparsebundles in cloud-synced folders.