[MUD-Dev] Guest Voices #2: Griefing in Online Games

J C Lawrence claw at kanga.nu
Thu May 12 20:11:20 New Zealand Standard Time 2005

On Tue, 10 May 2005 16:58:12 -0700
Shannon Appelcline <shannon.appelcline at gmail.com> wrote:

> I just posted the second Skotos Guest Voices article, "The Cost of
> Insecurity: Griefing, from Anonymity to Accountability". It can be
> found here:


> --<cut>--


> While there are numerous sources that can explain how digital
> signatures work, the important feature they support is
> non-repudiation. Non-repudiation is the property that only one
> individual could have signed a message. This works by taking advantage
> of the critical characteristic of public key cryptography. Namely,
> that knowing the public key (P) 'half' of a public-private key pair
> will not allow the reconstruction of the private (secret) key
> (S). Thus, I can broadcast my public key to everyone and they will be
> able to decrypt my messages, but only I can encrypt them.

> I can then use my private key to 'sign' a message by encrypting a hash
> of the message (or the message itself). Then, anyone can use my public
> key to validate my signature:


>  --<cut>--

PK crypto is a frequent suggestion for such problems but suffers from
two central problems:

  You cannot trust the client, and therefore, you cannot trust the
  client's security of its private key.  While there are ways to make
  this more difficult (eg 4 tuple registration against public keys on
  the server), it is inherently an insolvable problem in any perfect

  There is significant reward for an inimical player to ensure that
  their private keys are shared, and shared in a way which makes
  accurate detection and handling exceedingly difficult/expensive.
  Third party markets for game objects are now a significant business.
  We can safely assume that such operations will aggressively work,
  overtly and covertly, to maintain their business models. (eg customer
  support nightmare: inimical player simply steals, spoofs, and
  invalidates keys from opponents/challengers in a wholesale key
  laundering operation).

These problems are of course closely related to and exacerbated by the
set of problems based on free/readily_available trial/test/etc accounts.

As a BtB in researching this particular area you might like to read up
on the various analysies that have been done WRT applying such crypto
solutions in attempt to reduce the general spam problem.  Structurally
it is a fairly similar problem.

J C Lawrence                        They said, "You have a blue guitar,
---------(*)                        You do not play things as they are."
claw at kanga.nu                       The man replied, "Things as they are
http://www.kanga.nu/~claw/          Are changed upon the blue guitar."

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