Abstract (Markus Jakobsson)
A fair exchange of payments for goods and services is a barter
where one of the parties cannot obtain the item desired without
handing over the item he offered. We introduce the concept of
ripping digital coins to solve fairness problems in payment transactions.
We demonstrate how to implement coin ripping for a recently
proposed payment scheme, giving a practical and transparent coin
ripping scheme. We then give a general solution that can be used
in any payment scheme with a challenge. We also indicate how
fairness can be obtained by building a contract into the coin.
During the first part of the talk, basic digital cash issues will
be presented along with the cryptographic primitives to be used;
the second part will consist of the above mentioned coin ripping issues.
Last modified: May 23, 1995.
Kim Skak Larsen
(kslarsen@imada.sdu.dk)