5
$\begingroup$

What is the difference between Pseudo Random Functions and Random Oracles?

  1. Is the difference only about the domain of PRFs and Random Oracles, former having a fixed domain and latter can act on any input as long as it is well formatted?
  2. Having a Random Oracle is a stronger assumption, why is that?
$\endgroup$
  • $\begingroup$ Take a look at this for an intuitive definition of the random oracle $\endgroup$ – rath Apr 4 '14 at 0:34
10
$\begingroup$
  1. $\;\;\;$ No. $\:$ A PRF involves a secret key; a Random Oracle doesn't.

  2. $\;\;\;$ One can construct a PRF from a random oracle.

$\endgroup$
  • $\begingroup$ I'm not sure of 2), because a PRF is supposed to have a circuit representation (and it's a strong property). $\endgroup$ – Ievgeni Sep 20 at 12:20
0
$\begingroup$

Random oracles are purely random. They don't involve any cryptographic functions. They could be considered as the set of all functions that map an input to output. In that sense, a PRF could be considered a subset. Random oracles are stronger assumptions because they are totally random. The measure of a secure PRF is how indistinguishable it's from a Random Oracle. The more indistinguishable the better.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.