<s>
In	O
cryptography	O
,	O
a	O
multi-party	B-Protocol
fair	I-Protocol
exchange	I-Protocol
protocol	I-Protocol
is	O
protocol	O
where	O
parties	O
accept	O
to	O
deliver	O
an	O
item	O
if	O
and	O
only	O
if	O
they	O
receive	O
an	O
item	O
in	O
return	O
.	O
</s>
<s>
An	O
-party	O
single-unit	O
general	O
exchange	O
is	O
a	O
permutation	B-Algorithm
on	O
,	O
where	O
each	O
party	O
offers	O
a	O
single	O
unit	O
of	O
commodity	O
to	O
,	O
and	O
receives	O
a	O
single	O
unit	O
of	O
commodity	O
from	O
.	O
</s>
<s>
An	O
-party	O
multi-unit	O
general	O
exchange	O
is	O
a	O
matrix	B-Architecture
of	O
baskets	O
,	O
where	O
the	O
entry	O
in	O
row	O
and	O
column	O
is	O
the	O
basket	O
of	O
goods	O
given	O
by	O
to	O
.	O
</s>
