Link Password is a Firefox addon to encrypt your Firefox browser bookmarks using the symmetric AES cipher, you could combine Firefox Private Browsing mode that runs in RAM memory and does not save anything to your hard disk, with this privacy Firefox addon that will hide what your favourite sites are, it can be useful for those sharing computer at home or an Internet cafe, library, etc.
If you already have bookmarked link you can choose to encrypt them, Link Password can encrypt individual links or the folders containing them, it uses its own protocol “linkpassword“, the links can be renamed and rolled back if necesary, when you click on a link you will be asked for the password before it can be opened, decryption and encryption of bookmarks can be done with using a right click.
An alternative to Link Password would be to create an encrypted container and store Firefox Portable inside (including bookmarks), but encryption software like Truecrypt requires administrator rights and can not be used at libraries and Internet cafes where you are logged in as a user.