Encrypting the disk of your laptop with Ubuntu

I found it's kind of complicated to have your laptop have a fully encrypted disk. The instructions in the Ubuntu installer are not very intuitive. I found useful guidelines here.

In short:

You need the alternate installer cd for 32 or 64 bits. You need to select "expert install". Then, when you get to the disk partitioner:

- select "manual install"
- create a new partition table on your disk
- create a new partition of about 200Mb that you configure as ext4 file system, mount point is /boot, bootable flag on
- create a new partition of the remainder of your disk, use as "physical volume for encryption".

Now the complicated part.
Use the logical volume manager to create a logical volume group on your encrypted disk partition. In the logical volume group, create two logical volumes: a swap partition of a few Gb - you create a swap partition by creating a partition and selecting swap space - and an ext4 file system for the remainder of the disk. This ext4 file system should have / as the mount point.

Done!