Instal Lock On USB Stick

[weehaggis]

Is it possible to install some sort of lock on a USB stick AFTER the contents have been loaded on ? (i.e.: without deleting the contents)
Thanks

 

[rctlr]

Not really.
You need to encrypt the card.
If it's going from Mac to Mac format it with hfs and encryption. It will ask you for a password to format the card.
Every time you plug it into another Mac it will ask you for the same password to access it.
If it's gojng from Mac to pc then truecrypt is a good tool to encrypt the card.