What is meant by pseudo random function?

A function that can be used to generate output from a random seed and a data variable such that the output is computationally indistinguishable from truly random output. Source(s): NIST SP 800-108 under Pseudorandom function.

Do pseudo random functions exist?

Assuming the PRG conjecture, there exists a secure pseudorandom function generator. But before we see the proof of Theorem 4.4, let us see why pseudorandom functions could be useful.

What is PRF pseudo random function?

Definition The pseudorandom function (PRF) defined over (K, X, Y) is an efficient and deterministic function which returns a pseudorandom output sequence: F: K x X -> Y. Pseudorandom permutations can be defined in a similar way. They create output data indistinguishable from random sequences.

Is a hash a PRF?

No, the two primitives are definitely not the same. A pseudorandom function is a keyed function that is (computationally) indistinguishable from a function chosen at random from all functions with matching domain and range as long as the key remains secret.

What is CPA secure?

A chosen-plaintext attack (CPA) is an attack model for cryptanalysis which presumes that the attacker can obtain the ciphertexts for arbitrary plaintexts. The goal of the attack is to gain information that reduces the security of the encryption scheme.

What are pseudo random sequences?

A pseudorandom binary sequence (PRBS), pseudorandom binary code or pseudorandom bitstream is a binary sequence that, while generated with a deterministic algorithm, is difficult to predict and exhibits statistical behavior similar to a truly random sequence.

Why are pseudorandom numbers important?

Although sequences that are closer to truly random can be generated using hardware random number generators, pseudorandom number generators are important in practice for their speed in number generation and their reproducibility.

Are hash functions pseudorandom?

The hash function is chosen as a pseudo-random function, h() . Pseudo-random means that h() is a deterministic function, but from all tests, it appears to be random.

What is the main difference between PRF and PRNG?

1 Answer. Show activity on this post. Pseudorandom generators can be used to feed a pseudorandom function family by repeatedly supplying pseudo-random values to the function. The PRF ensures semantic security, which may be used to stretch keys, initialize vectors or salts.

What is meant by pseudo random number?

A set of values or elements that is statistically random, but it is derived from a known starting point and is typically repeated over and over.

Is AES a pseudo-random function?

While in practice, block ciphers are used in most instances where a pseudorandom function is needed, they do not, in general, constitute a pseudorandom function family, as block ciphers such as AES are defined for only limited numbers of input and key sizes.