[CF-Devel] Alchemy hashes

Tue Jun 8 02:23:53 CDT 2004

ERACC wrote:
>

      On Monday 07 June 2004 17:39

     >

      Nicolas Weeger wrote:

     >

     >

     >>

     Hello.

     >>

     >>

     Apparently, a player on cf.mf.net browsed alchemy code, and can now

     >>

     do a few formulea with food only (even if they aren't supposed to

     >>

     be done with that).

     >>

     Not really an exploit, as code specifically says that's possible.

     >>

     But still, maybe we'd need to make it harder to make items?

     >>

     >>

     Apparently it's just a matter of finding a good combination of

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     elements that sum up the same as target recipe.

     >>

     >>

     Just asking for opinions around :)

     >>

     >>

     Nicolas

     >

     >

     >

      IMO it is working as intended. If someone wants to take the time to

     >

      figure out alternative recipes then their reward is being able to use

     >

      them. I've been working on figuring out alternative recipes as well

     >

      so I obviously believe it should be left alone. :-)

  Well, just because the code is written in such a way does not mean it is 
correct.  Otherwise crossfire would be bug free.

  Now personally, I don't really have much a problem with random recipes.  The 
problem as I see it is that the recipes do a very simple hash, and so I'd say it 
is more out of game experimentation (or perhaps writing a simple script) to find 
alternative ways to make recipes.  And in fact, the hash is quite simple - I'd 
expect in an evening, I could write a script that could display all the possible 
recipe combinations out there.  And to me, that doesn't seem quite right.

  Now there are various ways around that - one could add some setting value that 
each server can customize - this setting would be added/multiplied/whatever to 
the hash string when attempting to do the recipes - thus, unless you knew that 
setting, it would be very difficult to find recipes outside the game.

  The hash code would have to be redone a bit - probably really want something 
more like a proper hash, eg:

  if (val & 800000) highbit=1;
  val <<= 1;
  val += tolower(character value) + element from setting;
  if highbit val |=1;

  Or something - looking at the code of actual checksum programs could be useful 
here.

  But all that really does it make it harder, depending on the max element from 
the setting.  Eg, if the max value is 100, that isn't all that hard for players 
to figure it out, and once they find that setting, it opens everything up - in a 
sense, that becomes more security through obscurity.

  The other thought I had, and perhaps a more clever thought, was to redo how 
the recipes are defined.  Instead of having the formulae file, you could instead 
do treasurelists.  For example, instead of:

#
# water of ruby
Object ruby
arch water
diff 10
exp 5000
chance 35
skill alchemy
cauldron cauldron
ingred 3 ruby,water of the wise

  Something like:

Object water
title ruby
randomitems recipe_water_ruby
...

and then have

treasure recipe_water_ruby
   arch ruby
     nrof 3
   more
   arch water of the wise
     nrof 1
end

So that allows for simple object comparision on recipes.  But the more clever 
idea is you could have random recipes, like:

treasure gem_encrusted_sword
   list swords
   more
   arch ruby
     chance 25
     no
     arch diamond
     chance 25
     no
       arch emerald
       end
     end
    end
   end

  So it grabs a weapon from the list of swords, and grabs one of those 3 gems, 
and generates a recipe,  You only need a few items and selection of items to now 
get a very big selection list.  For example, if the recipe has 3 items, but 
there are 10 different ones for each of those items, there is now 1000 combinations.

  Now my idea here is that as part of installation, or first run or whatever, 
the server generates those various lists and then write them out, so that they 
are static after that point.  Other settings could dictate if these show up in 
books or if only available by experimentation.  PRobably to do this, you'd need 
an object type RECIPE, and then perhaps even the formula file could go away.

  This has the advantage that it is now in game experimentation that may find 
these (and if you're a low level alchemist, you never really know if you had an 
invalid formula, or just failed on your roll).  But is also means that the 
formula arguably make more sense - transposing some letters or having a sum of 
letters that come up the same recipes doesn't make a whole bunch of sense (I 
know, its magic - it doesn't have to make sense), but something like above makes 
some sense - the objects to make the final project tie in with the object.

  But that's just my $.02

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