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Date: Fri, 11 May 2007 09:22:31 +0400
From: Solar Designer <>
Subject: Re: Q about "MaxLen" of incremental mode

> yl_changjiu <yl_changjiu@...> writes:
> > my hashes are like "I/2n0CZPaSkTI", "LHMfqiZfvP.eo" and so on.

On Fri, May 11, 2007 at 05:02:47AM +0000, -. -PhanTom-. - wrote:
> Well, those hashes are DES.
> And any words of more than 8 characters encrypted by DES will be truncated
> to 8 characters.

Those hashes use one of the DES-based hashing methods (the most common
one for Unix passwords), and this is hashing, not encryption.  You might
want to use the right words when speaking about this.  The differences
might appear subtle to you, but they are crucial.  Not all DES-based
hashing methods have this truncation property, and of those that do not
all truncate at 8 characters (for example, LM hashes are also DES-based,
but they split input passwords at 7 and truncate them after 14 characters).
If you were to actually encrypt something with DES (the block cipher)
rather than compute a hash, there would be different modes of operation
to choose from, but the input plaintext would not be truncated unless
you choose to process just one block or similar.

> milkshake -> milkshak
> hamburger -> hamburge

Yes, that's what happens for the traditional DES-based crypt(3).

Alexander Peslyak <solar at>
GPG key ID: 5B341F15  fp: B3FB 63F4 D7A3 BCCC 6F6E  FC55 A2FC 027C 5B34 1F15 - bringing security into open computing environments

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