Which parameters and design choices determine the actual algorithm of a Feistel cipher?

Answer 1

Block size: Larger block sizes mean greater security but reduced encryption/decryption speed. A block size of 64 bits is a reasonable tradeoff and has been nearly universal in block cipher design. However, the new AES uses a 128-bit block size.

Key size: Larger key size means greater security but may decrease encryption/decryption speed. Key sizes of 64 bits or less are now widely considered being inadequate and 128 bits has become a common size.

Number of rounds: The essence of the Feistel cipher is that a single round offers inadequate security but that multiple rounds offer increasing security. A typical size is 16 rounds.

Sub key generation algorithm: Greater complexity in this algorithm should lead to greater difficulty of cryptanalysis.

Round function: Again, greater complexity generally means greater resistance to cryptanalysis.

Answer 2

Block size: Larger block sizes mean greater security but reduced encryption/decryption speed. A block size of 64 bits is a reasonable tradeoff and has been nearly universal in block cipher design. However, the new AES uses a 128-bit block size.Key size: Larger key size means greater security but may decrease encryption/decryption speed. Key sizes of 64 bits or less are now widely considered being inadequate and 128 bits has become a common size.Number of rounds: The essence of the Feistel cipher is that a single round offers inadequate security but that multiple rounds offer increasing security. A typical size is 16 rounds.Sub key generation algorithm: Greater complexity in this algorithm should lead to greater difficulty of cryptanalysis.Round function: Again, greater complexity generally means greater resistance to cryptanalysis.

Answer 3

Parameter name