encrypt your secret file
jerryliang (10 points) | Mon, 2009-07-20 07:16i found lot of people on the forum have such a same problem, they donnt known how to encrypt your private files, or we can say there are few useful tool, but i dont think in this way. few days ago, i got Encryptionshield, and it is pretty nice, to be honest, it is fantastic. if you dont belive me, oh, forget it.
I believe you. You can also read these posts:
http://creativebits.org/mac_os_x/attach_secrets_keychain
A workaround is to create a diskimage with Disk Utility (in your Utilities folder) and turn on encryption. You can put your private files on the mounted image and unmount the disk. Be sure NOT to store the password in your keychain the first time you access the image ;)
Next time you mount the disk you will be asked for your password.