Encrypt Disk Using cryptsetup

How to setup an encrypted disk under linux using dm-crypt

Install and Mount

apt-get install cryptsetup
modprobe dm-crypt
cryptsetup luksFormat /dev/sda1
cryptsetup luksOpen /dev/sda1 crypt
mkfs.ext4 /dev/mapper/crypt
mount /dev/mapper/crypt /mnt/crypt