• Journal of Platform Technology
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• 제11권1호
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• pp.72-84
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• 2023

With the rise of the Internet of Things, the security of such lightweight computing environments has become a hot topic. Lightweight block ciphers that can provide efficient performance and security by having a relatively simpler structure and smaller key and block sizes are drawing attention. Due to these characteristics, they can become a target for new attack techniques. One of the new cryptanalytic attacks that have been attracting interest is Neural cryptanalysis, which is a cryptanalytic technique based on neural networks. It showed interesting results with better results than the conventional cryptanalysis method without a great amount of time and cryptographic knowledge. The first work that showed good results was carried out by Aron Gohr in CRYPTO'19, the attack was conducted on the lightweight block cipher SPECK-/32/64 and showed better results than conventional differential cryptanalysis. In this paper, we first apply the Differential Neural Distinguisher proposed by Aron Gohr to the block ciphers HIGHT and GOST to test the applicability of the attack to ciphers with different structures. The performance of the Differential Neural Distinguisher is then analyzed by replacing the neural network attack model with five different models (Multi-Layer Perceptron, AlexNet, ResNext, SE-ResNet, SE-ResNext). We then propose a Related-key Neural Distinguisher and apply it to the SPECK-/32/64, HIGHT, and GOST block ciphers. The proposed Related-key Neural Distinguisher was constructed using the relationship between keys, and this made it possible to distinguish more rounds than the differential distinguisher.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권8호
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• pp.4006-4024
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• 2017

Internet of Things (IoT) will transform our daily life by making different aspects of life smart like smart home, smart workplace, smart health and smart city etc. IoT is based on network of physical objects equipped with sensors and actuators that can gather and share data with other objects or humans. Secure communication is required for successful working of IoT. In this paper, a total of 13 lightweight cryptographic algorithms are evaluated based on their implementation results on 8-bit, 16-bit, and 32-bit microcontrollers and their appropriateness is examined for resource-constrained scenarios like IoT. These algorithms are analysed by dissecting them into their logical and structural elements. This paper tries to investigate the relationships between the structural elements of an algorithm and its performance. Association rule mining is used to find association patterns among the constituent elements of the selected ciphers and their performance. Interesting results are found on the type of element used to improve the cipher in terms of code size, RAM requirement and execution time. This paper will serve as a guideline for cryptographic designers to design improved ciphers for resource constrained environments like IoT.

• Journal of information and communication convergence engineering
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• 제14권3호
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• pp.177-183
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• 2016

A lot of Internet of Things devices has resource-restricted environment, so it is difficult to implement the existing block ciphers such as AES, PRESENT. By this reason, there are lightweight block ciphers, such as SIMON, SPECK, and Simeck, support various block/key sizes. These lightweight block ciphers can support the security on the IoT devices. In this paper, we propose efficient implementation methods and performance results for the Simeck family block cipher proposed in CHES 2015 on an 8-bit ATmega128-based STK600 board. The proposed methods can be adapted in the 8-bit microprocessor environment such as Arduino series which are one of famous devices for IoT application. The optimized on-the-fly (OTF) speed is on average 14.42 times faster and the optimized OTF memory is 1.53 times smaller than those obtained in the previous research. The speed-optimized encryption and the memory-optimized encryption are on average 12.98 times faster and 1.3 times smaller than those obtained in the previous studies, respectively.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권1호
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• pp.165-184
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• 2023

The ARX-based lightweight block cipher is widely used in resource-constrained IoT devices due to fast and simple operation of software and hardware platforms. However, there are three weaknesses to ARX-based lightweight block ciphers. Firstly, only half of the data can be changed in one round. Secondly, traditional ARX-based lightweight block ciphers are static structures, which provide limited security. Thirdly, it has poor diffusion when the initial plaintext and key are all 0 or all 1. This paper proposes a new dynamic ARX-based lightweight block cipher to overcome these weaknesses, called DABC. DABC can change all data in one round, which overcomes the first weakness. This paper combines the key and the generalized two-dimensional cat map to construct a dynamic permutation layer P1, which improves the uncertainty between different rounds of DABC. The non-linear component of the round function alternately uses NAND gate and AND gate to increase the complexity of the attack, which overcomes the third weakness. Meanwhile, this paper proposes the round-based architecture of DABC and conducted ASIC and FPGA implementation. The hardware results show that DABC has less hardware resource and high throughput. Finally, the safety evaluation results show that DABC has a good avalanche effect and security.

• Journal of Information Processing Systems
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• 제17권2호
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• pp.253-270
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• 2021

In January 2013, the National Institute of Standards and Technology (NIST) announced the CAESAR (Competition for Authenticated Encryption: Security, Applicability, and Robustness) contest to identify authenticated ciphers that are suitable for a wide range of applications. A total of 57 submissions made it into the first round of the competition out of which 6 were announced as winners in March 2019. In the process of the competition, NIST realized that most of the authenticated ciphers submitted were not suitable for resource-constrained devices used as end nodes in the Internet-of-Things (IoT) platform. For that matter, the NIST Lightweight Cryptography Standardization Process was set up to identify authenticated encryption and hashing algorithms for IoT devices. The call for submissions was initiated in 2018 and in April 2019, 56 submissions made it into the first round of the competition. In August 2019, 32 out of the 56 submissions were selected for the second round which is due to end in the year 2021. This work surveys the 32 authenticated encryption schemes that made it into the second round of the NIST lightweight cryptography standardization process. The paper presents an easy-to-understand comparative overview of the recommended parameters, primitives, mode of operation, features, security parameter, and hardware/software performance of the 32 candidate algorithms. The paper goes further by discussing the challenges of the Lightweight Cryptography Standardization Process and provides some suitable recommendations.

• 정보보호학회논문지
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• 제33권3호
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• pp.383-389
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• 2023

양자 컴퓨터의 발전 및 Shor 알고리즘, Grover 알고리즘과 같은 양자 알고리즘의 등장으로 인해 기존 암호의 안전성은 큰 위협을 받고 있다. 양자 알고리즘은 기존 컴퓨터에서 오랜 시간이 걸리는 수학적 작업을 효율적으로 할 수 있게 해준다. 이 특성은 수학적 문제에 의존하는 현대 암호 시스템이 깨지는 시간을 단축시킬 수 있다. 이러한 알고리즘을 기반으로 하는 양자 공격에 대비하기 위해서는 기존 암호를 양자회로로 구현해야 한다. 이미 많은 암호들은 양자회로로 구현되어 공격에 필요한 양자 자원을 분석하고 암호에 대한 양자 강도를 확인하였다. 본 논문에서는 LED 경량 블록암호에 대한 양자회로를 제시하고 양자회로의 각 함수에 대한 설명을 진행한다. 이후LED 양자회로에 대한 자원을 추정하고 다른 경량 블록암호와 비교하여 평가해보도록 한다.

• ETRI Journal
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• 제43권6호
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• pp.1113-1129
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• 2021

Lightweight ciphers are increasingly employed in cryptography because of the high demand for secure data transmission in wireless sensor network, embedded devices, and Internet of Things. The PRESENT algorithm as an ultralightweight block cipher provides better solution for secure hardware cryptography with low power consumption and minimum resource. This study generates the key using key rotation and substitution method, which contains key rotation, key switching, and binary-coded decimal-based key generation used in image encryption. The key rotation and substitution-based PRESENT architecture is proposed to increase security level for data stream and randomness in cipher through providing high resistance to attacks. Lookup table is used to design the key scheduling module, thus reducing the area of architecture. Field-programmable gate array (FPGA) performances are evaluated for the proposed and conventional methods. In Virtex 6 device, the proposed key rotation and substitution PRESENT architecture occupied 72 lookup tables, 65 flip flops, and 35 slices which are comparably less to the existing architecture.

• 전자공학회논문지
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• 제53권10호
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• pp.103-108
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• 2016

미래의 것으로 여겨지던 pervasive 컴퓨팅이 현재 널리 이용되고 있다. Pervasive 컴퓨팅의 단점으로 여겨지는 데이터의 유출문제는 데이터의 확실한 보호가 이루어진다면 크게 부각되지 않겠지만 해커들의 홈 네트워크를 통한 정보 수집 등과 같은 문제들이 발생하고 있다. Pervasive 디바이스는 일반적으로 소비 전력, 공간 및 비용 측면에서 제약을 가지고 있고 완벽한 암호화 환경의 구현은 현실적으로 불가하다. 따라서 연구의 초점은 가능한 적은 메모리를 필요로 하는 암호화 경량화에 집중하고 있다. 본 논문은 새로운 경량 블록 암호의 설계 및 구현에 초점을 두고 치환-순열(S-P) 네트워크와 파이스텔 구조의 장단점을 연구하여, 두 가지 네트워크의 이용시 가장 적합한 방향을 제시한다. 알고리즘은 S-박스 및 P-박스와 함께 파이스텔 구조를 사용한다. 본 논문에서는 백도어 아이디어가 알고리즘에 사용되는 것을 방지하기 위해 S-박스를 사용하였다. P-박스와 달리 S-박스는 키 디펜던트 원 스테이지 오메가 네트워크를 사용하여 보안 단계를 향상하였다. 본 논문에서 제안하는 하드웨어는 Verilog HDL로 설계되었으며 Virtex6 XC4VLX80 FPGA iNEXT-V6 테스트 보드를 사용하여 검증하였다. Simple core design은 337 MHz의 최대 클록 주파수에서 196 슬라이스를 합성한다.

• 한국컴퓨터정보학회논문지
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• 제23권10호
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• pp.111-117
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• 2018

CHAM is a lightweight block cipher, proposed in ICISC 2017. CHAM-n/k has the n-bit block and the k-bit key, and designers recommend CHAM-64/128, CHAM-128/128, and CHAM-128/256. In this paper, we study how to make optimal software implementation of CHAM such that it has high encryption speed on CPUs with high computing power. The best performances of our CHAM implementations are 1.6 cycles/byte for CHAM-64/128, 2.3 cycles/byte for CHAM-128/128, and 3.8 cycles/byte for CHAM-128/256. The comparison with existing software implementation results for well-known block ciphers shows that our results are competitive.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권7호
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• pp.3421-3437
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• 2018

With the enlargement of wireless technology, vehicular ad-hoc networks (VANETs) are rising as a hopeful way to realize smart cities and address a lot of vital transportation problems such as road security, convenience, and efficiency. To achieve data confidentiality, integrity and authentication applying lightweight cryptosystems is widely recognized as a rather efficient approach for the VANETs. The Khudra cipher is such a lightweight cryptosystem with a typical Generalized Feistel Network, and supports 80-bit secret key. Up to now, little research of fault analysis has been devoted to attacking Khudra. On the basis of the single nibble-oriented fault model, we propose a differential fault analysis on Khudra. The attack can recover its 80-bit secret key by introducing only 2 faults. The results in this study will provides vital references for the security evaluations of other lightweight ciphers in the VANETs.