encrypted home directory / wrapped-passphrase

[Basil Chupin]

On 20/07/12 07:26, scar wrote:
> hi i used the ecryptfs-migrate-home command to encrypt my home
> directory, and during that process i am told:
>
> ************************************************************************
> YOU SHOULD RECORD YOUR MOUNT PASSPHRASE AND STORE IT IN A SAFE LOCATION.
>    ecryptfs-unwrap-passphrase ~/.ecryptfs/wrapped-passphrase
> THIS WILL BE REQUIRED IF YOU NEED TO RECOVER YOUR DATA AT A LATER TIME.
> ************************************************************************
>
> so i run that command and get the ~/.ecryptfs/wrapped-passphrase file,
> which it seems to me should be moved elsewhere, like removable storage,
> since it sounds like this file is to be used when i forget my password.
>
> however, when i move that file, my home directory no longer gets
> decrypted when i log in and i get all these errors starting with one
> about .ICEauthority file or something.
>
> if i move that wrapped-passphrase file back to ~/.ecryptfs then things
> get decrypted when i log in.  so it seems like that file is necessary
> but its also stored in an unencrypted location for whomever steals my
> computer to use to decrypt my home directory, defeating the whole point
> of encryption.  i guess i'm obviously not understanding something here,
> can someone clarify?  thanks

You should look carefully into this question of encrypting your home 
directory.

Doing such an encryption of your home directory under the belief that 
you are actually making the data stored in /home totally secure is a 
delusion.

For example, on one of my computers I have the /home encrypted.

WOW, I thought. All this data is now safe!

Well, I have an external HDD which I use for backing up my /home 
directory. But what I found is that anyone can read that backed-up /home 
directory on the external HDD because once you copy it you lose all the 
encryption UNLESS you have the destination also encrypted. I won't 
explain further but I think I have my point.

Now for the next part.

I did an upgrade to my system - it was an upgrade of the kernel actually 
- after which I could not boot into the system. Nothing I tried to do 
could get me into the system using Rescue Disc etc etc because I had an 
encrypted /home directory and I needed to provide the passphrase in 
order to be able to access /home but nothing in the Rescue Disc asked me 
for such a passphrase - the only thing it was interested in was to be 
able to mount the /home partition, which, of course, was encrypted.

After fooling around for a few days and agonising about the thought of 
losing all data (some irreplaceable) in the /home directory, I 
discovered a few simple command line entries which completely bypassed 
the encryption I had on my /home directory and allowed me to boot into 
the system and fix up the mess created by the upgrade to the kernel! So 
much for encryption!

I then abandoned the whole idea of encrypting the /home directory as a 
complete waste of time and effort.

You want security and encryption? Then encrypt your whole 
installation/file system and not just your /home directory. But if you 
go this way it will be at a cost of slowing down the operation of your 
whole system.

Take some time off and read up about encryption/encrypting your file 
system - and NOT just your /home directory.

BC

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