Linked Questions

2 votes
2 answers
5k views

What is the difference between pseudorandom permutation/pseudorandom function/block cipher?

What is the difference between; pseudorandom permutation pseudorandom function block cipher? Very confused with the 3 terms and I am not good at advanced math. Can someone explain in plain word?
Mark's user avatar
  • 21
2 votes
2 answers
13k views

Certificate Signature Algorithm differs from Signature Algorithm Negotiated for Connection

With the upcoming sunsetting of SHA-1 by browsers I was checking signature algorithms for sites I visit. I'm using Firefox 43.0.2 on Windows. I noticed something interesting when I visited the site ...
Michael's user avatar
  • 123
1 vote
2 answers
110 views

Difference between PRF, Pseudorandom Function and Pseudorandom Function Family

According to Wikipedia, PRF is an abbreviation for Pseudorandom function family. But this answer says that PRF means Pseudorandom Function. Does that mean that a Pseudorandom Function is the same as a ...
Riemann's user avatar
  • 221
1 vote
2 answers
948 views

Pseudorandom Permutation equals to PRF?

I stuck on the same problem in a cryptography, as stated in this question I found following statement in famous textbook by J. Katz (main wiki PRP article refers to this textbook) PROPOSITION 3.27 ...
apatsekin's user avatar
  • 111
0 votes
2 answers
169 views

Are Block Ciphers Pseudorandom functions? [duplicate]

I am reading this page on wikipedia on Key derivation function here where it states: In cryptography, a key derivation function (KDF) is a cryptographic algorithm that derives one or more secret keys ...
Finlay Weber's user avatar
6 votes
1 answer
620 views

help with cryptanalysis of a sponge permutation

I have been studying and researching hash functions. So far my research has led me to the sponge construction. It appears that the permutation used in the sponge to stir the state is more or less ...
Ella Rose's user avatar
  • 19.6k
4 votes
1 answer
578 views

If a PRG is constructed by iterating a PRF, is it backtracking-resistant?

Say we construct a pseudo-random generator from a pseudo-random function $f$ (using some constant key $k$ and some initial value $v_0$). We do this by feeding the output block of the PRF back into the ...
user29077's user avatar
3 votes
1 answer
565 views

Can we use a PRF as a PRP?

Leaving aside the problem of how to compute the inverse of a PRF F, may we use it also as a PRP? The reciprocal of this statement is true, see for instance Katz and Lindell, Proposition 3.27, when ...
user1868607's user avatar
  • 1,243
1 vote
1 answer
76 views

PRP, PRF change at next selection?

This is probably a silly question, and similar question was asked before; but I can not figure out what actually is PRP/PRF. For example, it is commented that: A Pseudo Random Function is a ...
hola's user avatar
  • 603
1 vote
1 answer
1k views

How is a PRP different from PRF? Both can be inverted to get the same input

PRP is said to be a bijective function which means that there is a one-to-one mapping with the output. And hence the output can be inverted using the decryption algorithm to get the same input. ...
Saptarshi Basu's user avatar