how do I password protect a finder folder

OS X doesn't really allow individual folders to be protected. A third party app Espionage (http://www.taoeffect.com/espionage/) does this but by disguising a sparsebundle as an encrypted folder. Might suit your needs though.

Or, you can just create an encrypted sparse bundle directly and not bother with Espionage:

http://support.apple.com/kb/HT1578?viewlocale=en_US&locale=en_US

I don't understand why you need this. Seems better suited that you keep your own account to yourself, and set up another account for anyone else that you don't trust.

That's not secure and in any case someone could reset the admin password like here https://discussions.apple.com/thread/3749881?answerId=17642498022#17642498022

Well I guess it's time to turn on File-Vault then.

If the data isn't that much, you could just copy&paste it into the NOTES within the keychain, so it doesn't matter if someone rests the pw from the outside.

How to Password Protect a Folder in Finder:

· Open up the “Disk Utility” application

· Select “File” ➜ “New” ➜ “Disk Image from Folder...”

· Choose a folder to protect

· Click on “Image”

· Image Format:
select “Read / Write”

· NOTE:
The default Image Format is “Compressed”, this makes all files in the folder “Read – ONLY”, to change this option simply select “Read / Write” – and you will be able to continue reading and writing files.

· Encryption:
select “128-bit AES encryption (recommended)”

· Click “Save”

· Enter your desired new password twice

· WARNING – If You Forget This Password You Will Not Be Able To Access The Files Stored On This Image.
Forgotten Passwords Cannot Be Retrieved.