# What is the function of Feistel cipher?

## What is the function of Feistel cipher?

Feistel Cipher model is a structure or a design used to develop many block ciphers such as DES. Feistel cipher may have invertible, non-invertible and self invertible components in its design. Same encryption as well as decryption algorithm is used. A separate key is used for each round.

## What is the concept of Feistel cipher?

A Feistel cipher is a multi-round cipher that divides the current internal state of the cipher into two parts and operates only on a single part in each round of encryption or decryption.

What is the structure of the Feistel cipher?

As shown in Figure 2, the Feistel structure consists of multiple rounds of processing of the plaintext, with each round consisting of a substitution step followed by a permutation step. The input block to each round is divided into two halves that I have denoted L and R for the left half and the right half.

Which Boolean operation is used in Feistel cipher?

In a Feistel cipher, each round uses an operation called the F-function whose input is half a block and a round key; the output is a half-block of scrambled data which is XOR-ed into the other half-block of text.

### Which is a Feistel cipher network?

In cryptography, a Feistel cipher (also known as Luby–Rackoff block cipher) is a symmetric structure used in the construction of block ciphers, named after the German-born physicist and cryptographer Horst Feistel who did pioneering research while working for IBM (USA); it is also commonly known as a Feistel network.

### Why is AES not Feistel?

AES is an iterative rather than Feistel cipher. It is based on ‘substitution–permutation network’. Unlike DES, the number of rounds in AES is variable and depends on the length of the key. AES uses 10 rounds for 128-bit keys, 12 rounds for 192-bit keys and 14 rounds for 256-bit keys.

What is the difference between Feistel and non Feistel cipher?

1) The main difference between Feistel and non-feistel cipher is that non-feistel cipher uses only invertible components (i.e. the component in the encryption cipher has the same component in the decryption…