What is a Pricing Function
A pricing function is a function of the form y=
f(x) or a relation R such that pair (x,y) satisfies it, with the property that it is moderately hard (but not intractable) to compute, yet easy to verify.
The formal definition given by
Cynthia Dwork∞ and
Moni Naor∞ in their paper
"Pricing via Processing or Combatting Junk Mail"∞ is reproduced below:
A function
f is a pricing function if:
- f is moderately easy to compute
- f is not amenable to amortization: given l values m1 Â
ml, the amortized cost of computing f(m1) Â
f(ml) is comparable to f(mi) for any 1<=i<=l
- Given x and y it is easy to verify y = f(x)
A
difference parameter can be used to make the function
harder to compute for the sender.
HashCash and
MBound are pricing functions.
CategoryGeneral
