[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re:Negative reputations

szabo@netcom.com writes:
>Chaumian credentials also give the credential holder control over
>the transfer of credentials between his pseudonyms (hereafter "nyms"),
>creating an incentive to show positive credentials and hide
>negative ones.

In the various papers written by Chaum and others dealing with such
secure untracable credentials this issue is covered quite well as are
the means for dealing with this problem.  The credential protocols allow
one to perform secure boolean operations on the credentials, with
these operations one can require a user to construct a non-negative
credential.  To determine if a bank should lend money to a credential
holder the bank can require that the user present a credential which has
been signed by credit agencies stating that the user is not a credit risk.
To determine if a library should loan a book to a user it can require that
the user present a credential which shows that the user has not exceeded
the lending limit (the construction of such chained credentials is given
in Chaum's original paper and expanded in a paper in one of the later
Crypto proceedings, by Pfitzmann IIRC...)

The only situation which is a loose-end in the Chaumian credential system
are negative reputations where the user who wishes to hide the
negative reputation is not under any compulsion to present any information
to the other user (the "create, trash, and burn" identity cycle.)  A
good example of this are Usenet postings and current internet identity (or
lack thereof...) and the best answer to these situations seems to be
to treat the negative reputation just like a subjective potitive one and
have filtering mechanisms to raise the cost of entry into the "economy of
attention" to be a positive reputation.  There is nothing objective about
any reputation, positive or negative, so there is no particular reason to
treat a negative reputation any differently than a positive reputation;
the scale is simply subjective shades of grey.