I would like to know how high the level of entropy is when installing Ubuntu and encrypting the installation. As far as I know, the only partition that is not encrypted is the /boot partition because it has the boot loader unencrypted. When I use TrueCrypt to encrypt Windows, I am asked to move the mouse cursor inside the window to create a pool to improve the level of entropy.
As Ubuntu does not offer something like that, how can I be sure the keys, salts etc. are secure enough?