Creating an encrypted loopback device with Tomb
Tomb makes managing encrypted volumes easy - in fact very easy. This is a must if you're like me and want to store sensitive stuff on the cloud.
You can download Tomb from here.
1. Install some dependencies:
yum install ncurses-devel cryptsetup zsh gettext -y
yum install http://pkgs.repoforge.org/dcfldd/dcfldd-1.3.4.1-1.el6.rf.x86_64.rpm
2. Download and untar Tomb:
cd /tmp
wget https://files.dyne.org/tomb/Tomb-2.1.1.tar.gz
tar zxf Tomb-2.1.1.tar.gz
3. Make Tomb:
cd Tomb-2.1.1
make install
4. Add a user:
useradd -m weirdbricks
5. Dig a new tomb of the size you want - in this example I'm going to use 40GB (40960MB):
cd /home/weirdbricks
time tomb dig -s 40960 archived-photos.tomb
Output:
tomb . Commanded to dig tomb archived-photos.tomb
tomb (*) Creating a new tomb in archived-photos.tomb
tomb . Generating archived-photos.tomb of 40960MiB
40960+0 records in
40960+0 records out
42949672960 bytes (43 GB) copied, 8898.17 s, 4.8 MB/s
-rw------- 1 root root 40G Nov 2 07:56 archived-photos.tomb
tomb (*) Done digging archived-photos
tomb . Your tomb is not yet ready, you need to forge a key and lock it:
tomb . tomb forge archived-photos.tomb.key
tomb . tomb lock archived-photos.tomb -k archived-photos.tomb.key
real 148m18.280s
user 0m0.281s
sys 147m50.630s
As you can see from the output of time, creating the tomb can take a while :)
6. Create a key for the tomb - in this case we'll name the key "archived-photos.key":
tomb forge -f -k archived-photos.key
This will prompt you for the key's password twice
7. OK, now let's format the tomb and lock it - you will be asked for your password:
tomb lock -k archived-photos.key archived-photos.tomb
8. Finally let's open the tomb (mounts it!) - this will ask you for your password:
tomb open -k archived-photos.key archived-photos.tomb
9. You're good to go! Check the output of df -h to see the mounted Tomb:
df -h
Filesystem Size Used Avail Use% Mounted on
/dev/xvda1 50G 42G 5.7G 88% /
none 496M 0 496M 0% /dev/shm
/dev/mapper/tomb.archived-photos.1446525515.loop0
40G 48M 38G 1% /media/archived-photos
10. If you want to close the tomb (aka unmount it):
tomb close all