New modification on feistel DES algorithm based on multi-level keys

Abstract

The data encryption standard (DES) is one of the most common symmetric encryption algorithms, but it experiences many problems. For example, it uses only one function (XOR) in the encryption process, and the combination of data is finite because it occurs only twice and operates on bits. This paper presents a new modification of the DES to overcome these problems. This could be done through adding a new level of security by increasing the key space (using three keys) during the 16 rounds of the standard encryption algorithm and by replacing the predefined XOR operation with a new # operation. Our proposed algorithm uses three keys instead of one. The first key is the input key used for encrypting and decrypting operations. The second key is used for determining the number of bits, while the third key is used for determining the table numbers, which are from 0 to 255. Having evaluated the complexity of our proposed algorithm, the results show that it is the most complex compared with the well-known DES and other modified algorithms. Consequently, in our proposed algorithm, the attacker try a number of attempts 21173 at minimum to decrypt the message. This means that the proposed DES algorithm will increase the security level of the well-known DES.

Development of data encryption standard algorithm based on magic square

“…In 1972, IBM developed DES as the earliest symmetric encryption algorithm. The algorithm depends on Feistel structure that accepts 64-bit keys, where only 56-bits have already been used because the residual 8-bits were applied for error discovery purposes [12], [13]. The encryption process relies on a 56-bit secret key maps input block (64 bit) into a output block (64 bit).…”

Image Encryption Based on Multi-Level Keys on RC5 Algorithm

“…When the key space and the security are increased, so is making more double the encryption algorithms to intruders, the new manipulation bit process is added using the manipulated bit process variable truth table, which operates on four states {0, 1, 2, 3}, whereas the old traditional binary operation {XOR} works only on {0, 1} bits. The symbol (#) was used to indicate the performing of the operator, this operation using the 4-state truth tables as shown in Figure 2 [25,26].…”

A New Block Cipher Algorithm Using Magic Square of Order Five and Galois Field Arithmetic with Dynamic Size Block

“…The need for the devices currently in use prompted the change from relying on GF(P) to the use of polynomial numbers GF(2 8 ), as each Galois field will depend on the irreducible polynomial in its mathematical that used addition and multiplication [13]. Just as for each specific GF(2 Number ) there is a certain number of irreducible polynomials that can be used within that range, there are only 30 irreducible polynomials that can be used within GF (2 8 ) [14,17]. Before retrieving the original text, the work will be changed to a linear equation system and noting that the number of equations is equal to the number of unknowns to be solved.…”

“…before solving the work by Gaussian elimination or anyway is chosen requires arranging the equations in such a way that the main diagonal does not contain the value zero, and the final result of the Gaussian elimination method will restore the plain text [15,18]. Cryptography is a science that uses mainly mathematics to encode and decode data by using algorithms with the help of a key [14].…”

“…As for the first algorithm suggested, the data complexity will be the ASCII code number raised the message length used, which equals 16. As for the data complexity of the second algorithm suggested, it will have three states according to the message length used 10, 14, or 16, and the ASCII code itself is equal to 256, so the complexity in the data will be either (256) 10 , (256) 14 or (256) 16 (depending on the length of the message). As for the data complexity of the third algorithm suggested, it will be quite similar to the second algorithm.…”