dm-crypt.txt

# dm-crypt/Device encryption
https://wiki.archlinux.org/index.php/Dm-crypt/Device_encryption

1.dm-crypt kernel module configure.
$ sudo modprobe dm-crypt
$ sudo dmsetup targets
crypt            v1.10.0
mirror           v1.12.0
striped          v1.5.6
linear           v1.1.0
error            v1.2.0
2.encrypting devices with cryptsetup.
$ sudo dd if=/dev/zero of=~/secret.img bs=1M count=100
$ sudo losetup /dev/loop0 ~/secret.img
$ sudo cryptsetup -y create myEncryptedFilesystem /dev/loop0
$ sudo dmsetup ls
myEncryptedFilesystem (221, 0)

$ sudo mkfs.ext3 /dev/mapper/myEncryptedFilesystem
$ sudo mkdir /mnt/myEncryptedFilesystem 
$ sudo mount /dev/mapper/myEncryptedFilesystem /mnt/myEncryptedFilesystem
$ df -h /mnt/myEncryptedFilesystem 
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/myEncryptedFilesystem 97M 2.1M 90M 2% /mnt/myEncryptedFilesystem

$ sudo umount /mnt/myEncryptedFilesystem
$ sudo cryptsetup remove myEncryptedFilesystem