esafe is a bash script to create, mount, unmount and manipulate an encrypted filesystem using the cryptsetup program and the luks linux kernel extentions.
I find it useful, but there are no guarantees as to its usefulness.
For this script, the filesystem is created using /dev/zero and exists in /root/esafe.bin or the local directory you are in when esafe is started. The default used is the first instance found. This way you can keep an encrypted filesystem on a flash drive, cd there, and start esafe. When the filesystem is first created it will be in /root. You can move or copy it around from there.
The size is 250MB, but that can be changed in the create function.
Typing esafe (run as root. use 'sudo' or 'sudo su -') will show the various options and the filesystem status.
When mounted, the encrypted filesystem will reside on /mnt/container with permissions 757, owned by root.
Options to esafe are:
on: enable and mount
off: disable and unmount
status: show current status
new: build a new encrypted filesystem
addkey: add an additional key to the filesystem
delkey: delete an existing key
changekey: change an existing key
dump: show encrypted filesystem header info
Warning: deleting the final (only) key will disable the filesystem with no chance of recovery.
Place the file esafe in /usr/local/bin or where ever you keep your executables. Running esafe new will build a new encrypted filesystem. If your machine does not have /sbin/cryptsetup the esafe script will use apt-get install to install it. If your machine doesn't use apt-get you can manually install the cryptsetup programs.
Once the file /root/esafe.bin is fully created it can be copied as a backup. It can be kept on a usb flash drive.
---NOTE---
Ubuntu has started (and maybe others) using /dev/loop0-25 for their own uses.
esafe by default uses /dev/loop0
You WILL need to change the /dev/loop0 devices in esafe to /dev/loopNN for esafe to run correctly. Best way to do this is find the first unused device in /dev (in my case it was /dev/loop26) and create it:
sudo su - (change your user to root)
cd /dev
mknod /dev/loop26 b 7 26
chmod 660 /dev/loop26
then ls -la /dev/loop*
The new node should be the same permissions wise as the others.
You can (after changing /devloop0 to /dev/loop26 in esafe) then create a new container by running esafe new.
---NOTE---
NORMAL USE
With the esafe script in /usr/local/bin:
sudo su - (become root)
esafe on (start script, enter password used when created)
copy files to/from /mnt/container
esafe off (done. unload container)
exit (back to being a normal user)
While there are other ways to do this, this is probably the easiest.