Skip to main content
Cryptography

Return to Question

edited tags
Link
SEJPM
SEJPM
  • 46.4k
  • 9
  • 102
  • 210
removed bogus line breaks
Source Link
Gilles 'SO- stop being evil'
Gilles 'SO- stop being evil'
  • 20.1k
  • 4
  • 53
  • 96

The Luby-Rackoff theorem states that if a round function is a secure pseudorandom function (PRF)
 then 3 rounds are sufficient to make the block cipher a pseudorandom permutation (PRP).

PRPs are invertible whereas PRFs are not. How come 3 rounds of a PRF
  will make an invertible block cipher out of a non-invertible function?

The Luby-Rackoff theorem states that if a round function is a secure pseudorandom function (PRF)
 then 3 rounds are sufficient to make the block cipher a pseudorandom permutation (PRP).

PRPs are invertible whereas PRFs are not. How come 3 rounds of a PRF
  will make an invertible block cipher out of a non-invertible function?

The Luby-Rackoff theorem states that if a round function is a secure pseudorandom function (PRF) then 3 rounds are sufficient to make the block cipher a pseudorandom permutation (PRP).

PRPs are invertible whereas PRFs are not. How come 3 rounds of a PRF will make an invertible block cipher out of a non-invertible function?

Tweeted twitter.com/#!/StackCrypto/status/499730873278029824
fixed typo and changed spacing
Source Link
user991
user991

Luby-Rackoff theorem confustionconfusion

The Luby-Rackoff theorem states that if a round function is a secure pseudorandom function (PRF) then
then 3 rounds are sufficient to make the block cipher a pseudorandom permutation (PRP).

PRPs are invertible whereas PRFs are not. How come 3 rounds of a PRF will
will make an invertible block cipher out of a non-invertible function?

Luby-Rackoff theorem confustion

The Luby-Rackoff theorem states that if a round function is a secure pseudorandom function (PRF) then 3 rounds are sufficient to make the block cipher a pseudorandom permutation (PRP).

PRPs are invertible whereas PRFs are not. How come 3 rounds of a PRF will make an invertible block cipher out of a non-invertible function?

Luby-Rackoff theorem confusion

The Luby-Rackoff theorem states that if a round function is a secure pseudorandom function (PRF)
then 3 rounds are sufficient to make the block cipher a pseudorandom permutation (PRP).

PRPs are invertible whereas PRFs are not. How come 3 rounds of a PRF
will make an invertible block cipher out of a non-invertible function?

Source Link
BlaX
BlaX
  • 746
  • 8
  • 18