Question about history of hash and cipher collections

David Shaw dshaw at
Mon Jan 14 05:24:23 CET 2008

On Sun, Jan 13, 2008 at 09:15:42PM -0600, Kevin Hilton wrote:
> Sorry the last post was cut off
> Sorry about my post
> I can see you seem to know a lot about gpg -- thanks.
> Whatever happened to the tiger hash??

Tiger was never really a part of OpenPGP.  RFC-2440 reserved an
algorithm ID number for it, but Tiger wasn't fully specified at the
time, so was not usable (the algorithm was specified, but an OID
number was never allocated).  It was dropped as part of RFC-4880 as it
was never widely implemented, and sort of missed its chance - it was
okay back when 2440 was published, but at only 192 bits, it's too
small for the modern 4880 era.

> Lastly, do you know the reason that the serpent cipher algorithm never
> made it into gpg.  From the NSA competition, I thought the serpent
> algorithm came in second --- again Im not sure of the criteria that
> was used to judge strength -- but wasnt it from this competition that
> the US gov adopted AES as the national standard?  Just a question, b/c
> from my very elementary understanding of ciphers, it seems like
> serpent is a very secure standard.  I believe looking at the source
> code (either in pgg or pgp2 -- I cant remember) I even saw a serpent.c
> file.

Serpent was never put in the OpenPGP standard, so GnuPG won't use it.
There isn't a really dramatic reason for it.  Adding algorithms to
OpenPGP involves a rough consensus among the OpenPGP working group.
With Serpent, that consensus never really happened.


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