Re: Problem with DES

[Gisle S{lensminde <gisle@ii.uib.no>]

On Thu, 4 Jan 2001, Pierre PEIFFER wrote:

> Pierre PEIFFER wrote:
>
> > Hello everybody and happy new year !
> >
> >     I have problem with DES, I use kernel patch 2.2.17.10 with kernel
> > 2.2.13 and I have the following problem:
> >     losetup return "ioctl: LOOP_SET_STATUS: Invalid argument".
> >
> >     Since rijndael encryption works very well and since a message "Use
> > of DES is deprecated", I was worrying if DES is still well supported and
> > maintained ?

Not really. DES is not considered secure by today's standards, and
it's not maintained in kerneli. Unless you have an old
DES-encrypted partition, you should not use it, since there's
ciphers that is both faster and more secure than DES. Your problems
regarding the key indicated that you not have such a partition. :-)

Your problem is that you for DES (unlike the other cipher inkl 3DES)
must specify the key in hexadecimal, and the key must have the
parity bits correctly set. For the other ciphers, it's sufficient
to enter a passphrase, which then is hashed into the actual key.
To calculate the parity is not that easy, but since DES is deprecated
nobody have bothered to fix this problem. I don't even know if DES
works, since I never bothered to calculate a key with correct
parity manually. For 3DES the parity is calculated automatically.

If you have an old DES-encrypted partition somewhere, I can help you.
Otherwise I recoment either Rijndael/AES, serpent or blowfish.

--
Gisle Sælensminde ( gisle@ii.uib.no )

With sufficient thrust, pigs fly just fine. However, this is not
necessarily a good idea. It is hard to be sure where they are going
to land, and it could be dangerous sitting under them as they fly
overhead. (from RFC 1925)


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