Ask Max: Locking a single folder
I am looking for a way to lock a folder on my computer (all my financials etc.) with others in the house. I would rather not log in and out of my computer to do this. Any thoughts?Willing to buy additional software that would make it easy. In the Mac OS you can lock the file, but that is only so you cannot throw it away.
Folder level security is a frequently requested feature. Although there are third party utilities that help you do this, OS X will provide you with free tools that will work for you. If you are looking for a low security way to drop files into a lockbox folder, you can do that with Folder Permissions. Create a folder and click on it once to highlight it. Then Hold down the Command key and "I" key to get the "Info" window. Go to the Permissions section and change all the popup menus to "Write only (Drop-Box)." You may have to unlock the permissions popup menus by clicking on the little padlock icon and entering the Admin password. The folder method is flawed. First, to open the folder you have to change the permissions to Read-Write before you can use it and then change it back when you are done. Second, anyone with the Admin password for your Mac can unlock the folder. So the security is light, and the use is kludgy (can you tell I do not like it?).The best way of securing files on your hard drive is not with a folder, but an encrypted disk image. Open Disk Utility from the Utilities folder, it's found inside the Applications folder. In Disk Utility, go to the File menu and down to the "New" submenu. There select "New Blank Image." Give it a name and select the place to save it. Now you will need to set a volume size. This will take some thought because you can't change the size later. Additionally, the image will use the same amount of hard drive space whether empty or full; so don't make it too large. The last change to make here is to set the Encryption popup menu to "128-bit AES" encryption. Click the create button and you will soon be prompted to enter a Password. Make it a good password but know there is no way to open it without the password, so you can't forget it. The last thing to do is uncheck the "Remember Password in Keychain" checkbox. It could take a long time to create the image, depending on how large you made it.When using this disk image, make sure that the password is never remembered in the Keychain. There will often be a checkbox when entering your password, just don't mark the checkbox. Otherwise, everyone will be able to mount the disk image without the password. Now all you have to do to work with the secret files is double-click on the disk image and enter your password. When you are done, just eject the mounted disk. It is a simple and rock-solid security solution.