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Re: Linux disk partition encryption



Thanks everyone who commented. 

On Thu, 27 Jan 2011 00:07:21 +0100, tv.debian@googlemail.com wrote:

>> - First very noob question, I don't want whole disk encryption, just
>> want to encrypt some selected already partitioned partitions. If
>> someone mount those encrypted partitions, will they shows up as empty
>> or, there are some hints that the partitions have been encrypted?
> 
> Don't know what you mean exactly by "show up as empty", with ecryptfs
> the mountpoint will indeed be empty unless the crypted directory is
> open. . . 

My this question seems to have confused most people. What I wanted to 
know is how would the partition appears to normal Joe. Now my 
understanding is the following. are they correct? 

The encrypted partition will appear as unformatted -- with no files 
system on it, if you just simply want to do 'mount /dev/sdx' (just like 
how Linux partitions normally appear to Windows). Even if one read its 
physical sections, they will appear as "random" numbers. Oh, wait, 
cryptsetup, has a pretty standard header, so an expert can at least tell 
that the partition is encrypted with cryptsetup, but whether he can 
decipher or not is a different story.

Is about correct? 

Further, does disk encryption access the partition directly? I mean, does 
the 'cryptsetup luksFormat /dev/sdxn' care what type of partition 
(ext2/3, fat, etc) /dev/sdxn is? 

Now another question, which nobody seems to have noticed/mentioned. 

Since CBC encryption is a "recursive algorithm, the encryption of the n-th 
block requires the encryption of all preceding blocks, 0 till n-1." [1]
Now, does it mean if my HD has a bad block in the middle, then all the 
remaining data will be gone entirely?

1. http://clemens.endorphin.org/LinuxHDEncSettings

Thanks

-- 
Tong (remove underscore(s) to reply)
  http://xpt.sourceforge.net/techdocs/
  http://xpt.sourceforge.net/tools/


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