Re: 2.4 and cryptofs on raid1 - what will be cached and how many times

[Bryan Andersen <bryan@bogonomicon.net>]

Vlad Harchev wrote:

>>A potential attacker can use this to look for the ext2 superblock,
>>which gives him the same data both encrypted an unencrypted. A real
> 
>  
>  I've got an impression that in case of loopback with encryption the 
> superblock will also be encrypted. 
>  If one forgets known cleartext attacks, one can place the filesystem at
> some offset.

Yes it would be encrypted.  Unfortunately it is predictable data and as 
such it is much easier to crack.  Better set that offset at a location 
computed from the encryption key.

On a side note I find it interesting that many people sugest compressing 
a file before encrypting it.  Take a look at the first few bytes of 
every compressed file.  Unless your going to get rid of that header...

>>cryptofs would go through great pains to take such advantages away.

- Bryan