# Modified Generalized Feistel Network Block Cipher for the Internet of Things
## 2 Related Work
Nevertheless, [41] provides a chosen plaintext attack that employs a differential analysis against the full-round cipher. [PERSON] et al. [42] proposed a novel approach to enhance the security and efficiency of the data encryption standard (DES) with their lightweight variant, the DESL, utilizing a serial hardware architecture and a single S-Box in place of the original eight S-Boxes. The S-Box was meticulously optimized to decrease the gate complexity, resulting in a resistance to common attacks, such as linear and differential cryptanalysis and the Davies-Murphy attack. The DESL achieves a security level suitable for many applications and is more resistant to linear cryptanalysis than the DES, as a result of the improved non-linearity of the S-Box. However, the DESL's key size is no longer practical and is now vulnerable to brute-force attacks. ITUbee [43] is a recently proposed lightweight encryption that has been created exclusively for 8-bit software-based devices. It employs a Feistel structure and consists of 80-bit keys and 80-bit blocks. ITUbee utilizes round-dependent constants rather than a \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Lightweight** & **Rounds** & **Key Size** & **Block Size** & **Weaknesses** \\
**Block Cipher** & & & & \\ \hline RC5 & 0–255 & 128 & 64 & Differential-key attacks. \\ TEA & variable & 128 & 64 & Related-key attacks. \\ XTEA & variable & 128 & 64 & Related-key rectangle attacks on 36 rounds. \\ DESL & 16 & 56 & 64 & Size of the key. \\ ITUBEE & - & 80 & 80 & Self-similarity cryptanalysis. \\ SIMON & 32, 36, 42, 44, 52, & 64, 72, 96, 128, 144, & 32, 48, 64, 96, 128 & Attacks on reduced versions—differential \\  & 54, 68, 69, 72 & 192, 256 & fault analysis. \\ ANU & 25 & 80/128 & 64 & Related-key boomerang attacks. \\ PICCOLO & 25, 31 & 80, 128 & 64 & Biclique cryptanalysis. \\ SLIM & 32 & 80 & 32 & Size of the key. \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Comparisons of Feistel-based lightweight block ciphers. strong key schedule. Although this strategy is meant to improve ITUbee's efficacy, a self-similarity cryptanalysis performed in [44] reveals that it is ineffective. The cryptanalysis proves that the reduced round form of the encryption can be distinguished from a perfect random permutation. In addition, a deterministic related-key differential distinguisher for the 8-round version of the single-key model is described, decreasing the cipher's security by one bit. The NSA invented the SIMON [45] cipher, which is efficient in both software and hardware. It supports multiple key and block sizes, including 64-, 72-, 96-, 128-, 144-, 192-, and 256-bit key sizes, and 32-, 48-, 64-, 96-, and 128-bit block sizes. In addition, it supports a variety of round numbers, including 32, 36, 42, 44, 52, 54, 68, 69, and 72. Several separate cryptanalysis attempts on SIMON have yielded insights into the cipher's design and attacks on its reduced-round variants [46]. However, differential fault attacks on SIMON are outlined in [47]. Moreover, [48] demonstrates that cube and dynamic cube attacks on SIMON with a 64-bit key and 32-bit block can recover the complete key in a feasible amount of time. ANU [16] is a block cipher with a small memory footprint and low power consumption. It supports 128-bit or 80-bit key lengths with a remarkably small chip area of only 1015 GE for 128-bit keys. ANU demonstrates a high level of resistance to linear and differential attacks, biclique cryptanalysis, and zero-correlation attacks, making it an attractive option for a variety of cryptographic applications. Recent research [49] demonstrates that ANU is vulnerable to related-key boomerang attacks. PICCOLO [23] is a novel variation of the generalized Feistel network (GFN) block cipher introduced by [PERSON] et al. PICCOLO is intended to handle a 64-bit block cipher, with key sizes of 80 or 128 bits, and can run for 25 or 31 cycles. The F-function of PICCOLO consists of two S-box layers separated by a diffusion matrix, with the key applied only before the second S-box layer.