Substitution-Permutation Network Structure Research Articles

Fast lightweight block cipher design with involution substitution permutation network (SPN) structure

<p>In the present paper, a new cryptographic lightweight algorithm has been developed for the Internet of Things (IoT) applications. The submitted cipher designed with the involution Substitution Permutation Network SPN structure. The involution structure means that the same encryption algorithm is used in the decryption process except the ciphering key algorithm is applied in reverse order. The introduced algorithm encrypts the data with a block size of 128-bit 192-bit or 256-bit, which iterative with 10, 12 and 14-rounds respectively similar to the AES cipher. The design aspect supports an elegant structure with a secure involution round transformation. The main round is built without S-Box stage instead that it uses the on-fly immediate computing stage and the involution of mathematical invertible affine equations. The proposed cipher is adopted to work in a restricted environment and with limited resources pertaining to embedded devices. The proposed cipher introduces an accepted security level and reasonable Gate Equivalent (GE) estimation with fast implementation.</p>

Information Theory-Based Quantitative Evaluation Method for Countermeasures Against Fault Injection Attacks

The integrated circuits are faced with the threats of fault injection attacks (FIAs), which employ the faulty results and differential fault analysis to retrieve the vital information processed by the circuits. Countermeasures should be taken to protect the circuits against FIAs. This paper proposes a security evaluation method to quantitatively analyze the resistance of block ciphers with a Substitution-Permutation Network structure against FIAs from an information-theoretic perspective. A quantitative security factor is defined based on the amount of information leakage. Specifically, an extended cipher model is proposed to numerically analyze the theoretical amount of information leakage, and an efficient approach is proposed to obtain the actual amount of information leakage. Experiments by applying the quantitative evaluation method to AES circuit validate feasibility, efficiency and scalability of the method. The experimental results show that the security factor can quantify the effects of different fault models and countermeasures. 2000 fault injections are sufficient to complete the evaluation under the considered fault models within 10 microseconds. The proposed method can be used during the circuit design stage as well as chip testing stage.

SFN: A new lightweight block cipher

During past few years, some lightweight block ciphers have been proposed. These lightweight block ciphers take single encryption method that either uses Substitution-Permutation (SP) network structure or Feistel network structure to encrypt. In this paper, we have designed a different encryption method that takes both SP network structure and Feistel network structure to encrypt. Current SP network has a limitation that the encryption and decryption processes are dissimilar. To solve this problem, we have employed involution related properties of the nonlinear and linear components to modify SP network structure. The modified one enables the encryption and decryption program or circuit to work as the Feistel network structure. Additionally, we have implemented a MixRows in SP network structure. Then we instantiate these three novel ideas into the lightweight block cipher called SFN. We have carried out the security evaluation and the hardware and software experiments to it. The result shows that compared to other lightweight block ciphers, SFN has more advantages in terms of being immune to attacks. Also, SFN is not only compact in hardware environment but also efficient in software platforms.

Pengembangan Algoritma Advanced Encryption Standard pada Sistem Keamanan SMS Berbasis Android Menggunakan Algoritma Vigenere

Short Message Service (SMS) is working on a wireless network that allows the theft of the message contents. There are risks that could threaten the security of the contents of the message on SMS services, including SMS snooping, and SMS interception. Therefore, it takes security system messages on SMS services to maintain the security and integrity of the message content to cover the security messages. Algorithms Advanced Encryption Standard (AES) using a structure SPN (Substitution Permutation Network) structure, which has the disadvantage of encryption and decryption, so the safety level is low. To cover the security hole of these weaknesses, the researchers conducted the improvement of Advanced Encryption Standard (AES) algorithm security system based on android SMS using Vigenere algorithm, so that the level of security and integrity of the content of the short message becomes higher and difficult to solve. The results showed an average increase in percentage value of the avalanche effect from 37.24% to 42.96%.
 Keywords—Advanced Encryption Standard, android, message security, encryption.

New differentially 4-uniform permutations by modifying the inverse function on subfields

Permutations over ??22k$\mathbb {F}_{2^{2k}}$ with low differential uniformity, high algebraic degree and high nonlinearity are of great cryptographic importance since they can be chosen as the substitution boxes (S-boxes) for many block ciphers with SPN (Substitution Permutation Network) structure. A well known example is that the S-box of the famous Advanced Encryption Standard (AES) is derived from the inverse function on ??28$\mathbb {F}_{2^{8}}$, which has been proved to be a differentially 4-uniform permutation with the optimal algebraic degree and known best nonlinearity. Recently, Zha et al. proposed two constructions of differentially 4-uniform permutations over ??22k$\mathbb {F}_{2^{2k}}$, say Gt and Gs, t with Tr(s?1) = 1, by applying affine transformations to the inverse function on some subfields of ??22k$\mathbb {F}_{2^{2k}}$ (Zha et al. Finite Fields Appl. 25, 64---78, 2014). In this paper, we generalize their method by applying other types of EA (extended affine) equivalent transformations to the inverse function on some subfields of ??22k$\mathbb {F}_{2^{2k}}$ and present two new constructions of differentially 4-uniform permutations, say F? and Fs, ? with Tr(s?1) = 1. Furthermore, we prove that all the functions Gt with different t are CCZ (Carlet-Charpin-Zinoviev) equivalent to our subclass F0, while all the functions Gs, t with different t are CCZ-equivalent to our subclass Fs,0. In addition, both our two constructions give many new CCZ-inequivalent classes of such functions, as checked by computer in small numbers of variables. Moreover, all these newly constructed permutations are proved to have the optimal algebraic degree and high nonlinearity.

Impossible differential cryptanalysis on cipher E2

SUMMARYE2, a block cipher, is an Advanced Encryption Standard candidate designed and submitted by Nippon Telegraph and Telephone Corporation. It employs a Feistel structure as global structure and two‐layer substitution–permutation network structure in round function. The conservative structure makes E2 immune to kinds of current cryptanalysis. Previously, there is no result of impossible differential attacks on E2 because it was once supposed to have no more than five‐round impossible differential characteristic. In this paper, we present a series of six‐round impossible differential characteristics of E2 with/without initial transformation (IT)/ final transformation (FT) functions. Based on these impossible differentials, the immunity of E2 against impossible differential cryptanalysis is evaluated. We perform a seven‐round attack on tweaked E2 (E2 without IT and FT ) with 128, 192, and 256 bits key and an eight‐round attack on tweaked E2 with 256 bits key. The seven‐round attack requires about 2120 chosen plaintexts and 2115.5 seven‐round encryptions; the eight‐round attack needs 2121 chosen plaintexts and less than 2214 eight‐round encryptions. We also discuss the seven‐round attack on E2 with IT or FT, and the result shows that the attack has the same complexities with the seven‐round attack on tweaked E2. Copyright © 2013 John Wiley & Sons, Ltd.

A New Differential Fault Attack on SPN Structure, with Application to AES Cipher

The Substitution-Permutation Network (SPN) is a main type of structure in block ciphers. This paper proposes a new and practical differential fault attack technique on SPN structure. As an instance of SPN cipher , AES-256 can be recovered by 4 faulty ciphertexts. Compared with the previous techniques, our work can recover all subkeys of a n SPN cipher with all key s izes. Therefore , our attacking method on AES not only improves the efficiency of fault injection, but also decreases the number of faulty ciphertexts. It provides a new approach for fault analysis on block ciphers.

Perfect involutory diffusion layers based on invertibility of some linear functions

One of the most important structures used in modern block ciphers is the substitution-permutation network (SPN) structure. Many block ciphers with this structure widely use Maximun Distance Separable (MDS) matrices over finite fields as their diffusion layers, for example, advanced encryption standard (AES) uses a 4-4 MDS matrix as the main part of its diffusion layer and the block cipher Khazad has an involutory 8-8 matrix. In this study, first a construction is proposed for a 4-4 linear diffusion layer that can intermix four words of arbitrary size with branch number 5. Then extend this idea for 8-8 diffusion layer using low-cost linear functions. In this construction, first, certain binary linear combinations of inputs are fed into two or three different invertible linear functions and then combined using XOR operation. In order to show the efficiency of the proposed diffusion layer, the authors exploit it in a nested SPN structure and compare its efficiency with some well-known diffusion layers such as the diffusion layer of Hierocrypt.