• KIPS Transactions on Computer and Communication Systems
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• v.10 no.4
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• pp.101-106
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• 2021

Quantum algorithms and quantum computers can break the security of many of the ciphers we currently use. If Grover's algorithm is applied to a symmetric key cipher with n-bit security level, the security level can be lowered to (n/2)-bit. In order to apply Grover's algorithm, it is most important to optimize the target cipher as a quantum circuit because the symmetric key cipher must be implemented as a quantum circuit in the oracle function. Accordingly, researches on implementing AES(Advanced Encryption Standard) or lightweight block ciphers as quantum circuits have been actively conducted in recent years. In this paper, korean lightweight block cipher LEA was optimized and implemented as a quantum circuit. Compared to the previous LEA quantum circuit implementation, quantum gates were used more, but qubits were drastically reduced, and performance evaluation was performed for this tradeoff problem. Finally, we evaluated quantum resources for applying Grover's algorithm to the proposed LEA implementation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.229-231
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• 2021

In this paper, we describe a hardware design of the SIMECK block cipher algorithm that can be implemented in lightweight hardware with appropriate security strength. To achieve fast encryption and decryption operations, it was designed using two-step method that reduces the number of operation rounds. The designed SIMECK cryptographic core was implemented in Arty S7-50 FPGA device and its hardware operation was verified with a GUI using Python.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.29 no.3
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• pp.477-489
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• 2019

In this paper, we experimentally verify the expected differential probability under the markov cipher assumption and the distribution of the differential probability. Firstly, we validate the expected differential probability of 6round-PRESENT of the lightweight block cipher under the markov cipher assumption by analyzing the empirical differential probability. Secondly, we demonstrate that even though the expected differential probability under the markov cipher assumption seems valid, the empirical distribution does not follow the well-known distribution of the differential probability. The results was deduced from the 4round-GIFT. Finally, in order to analyze whether the key-schedule affects the mis-matching phenomenon, we collect the results while changing the XOR positions of round keys on GIFT. The results show that the key-schedule is not the only factor to affect the mis-matching phenomenon. Leveraging on GPGPU technology, the data collection process can be performed about 157 times faster than using CPU only.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.4
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• pp.719-726
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• 2015

As big-data and cloud security technologies become popular, many researchers have recently been conducted on faster and lighter encryption. As a result, National Security Research Institute developed LEA which is lightweight and fast block cipher. To date, there have been various studies on lightweight encryption algorithm (LEA) for speeding up using GPU rather than conventional CPU. However, it is rather difficult to explore any guideline how to manipulate the GPU for the efficient usage of the LEA. Therefore, we introduce a guideline which explains how to implement and design the optimal LEA using GPU.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.05a
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• pp.163-165
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• 2018

GF(p)상 타원곡선 암호(ECC)와 RSA를 단일 하드웨어로 통합하여 구현한 공개키 암호 프로세서를 설계하였다. 설계된 EC-RSA 공개키 암호 프로세서는 NIST 표준에 정의된 소수체 상의 224-비트 타원 곡선 P-224와 2048-비트 키 길이의 RSA를 지원한다. ECC와 RSA가 갖는 연산의 공통점을 기반으로 워드기반 몽고메리 곱셈기와 메모리 블록을 효율적으로 결합하여 최적화된 데이터 패스 구조를 적용하였다. EC-RSA 공개키 암호 프로세서는 Modelsim을 이용한 기능검증을 통하여 정상동작을 확인하였으며, $0.18{\mu}m$ CMOS 셀 라이브러리로 합성한 결과 11,779 GEs와 14-Kbit RAM의 경량 하드웨어로 구현되었다. EC-RSA 공개키 암호 프로세서는 최대 동작주파수 133 MHz이며, ECC 연산에는 867,746 클록주기가 소요되며, RSA 복호화 연산에는 26,149,013 클록주기가 소요된다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.2
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• pp.457-465
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• 2015

Internet of Things(IoT) technologies should be able to communication with various embedded platforms. We will need to select an appropriate cryptographic algorithm in various embedded environments because we should consider security elements in IoT communications. Therefore the lightweight block cryptographic algorithm is essential for secure communication between these kinds of embedded platforms. However, the lightweight block cryptographic algorithm has a vulnerability which can be leaked in side channel analysis. Thus we also have to consider side channel countermeasure. In this paper, we will propose the scenario of side channel analysis and confirm the vulnerability for HIGHT algorithm which is composed of ARX structure. Additionally, we will suggest countermeasure for HIGHT against side channel analysis. Finally, we will explain how much the effectiveness can be provided through comparison between countermeasure for AES and HIGHT.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.32 no.2
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• pp.163-170
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• 2022

LEA is a lightweight block cipher developed in Korea in 2013. In this paper, among block cipher operation methods, CTR operation mode and GCM operation mode that provides confidentiality and integrity are implemented. In the LEA-CTR operation mode, we propose an optimization implementation that omits the operation between states through the state fixation and omits the operation through the pre-operation by utilizing the characteristics of the fixed nonce value of the CTR operation mode. It also shows that the proposed method is applicable to the GCM operation mode, and implements the GCM through the implementation of the GHASH function using the Galois Field(2¹²⁸) multiplication operation. As a result, in the case of LEA-CTR to which the proposed technique is applied on 32-bit RISC-V, it was confirmed that the performance was improved by 2% compared to the previous study. In addition, the performance of the GCM operation mode is presented so that it can be used as a performance indicator in other studies in the future.

• Proceedings of the Korea Information Processing Society Conference
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• 2021.05a
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• pp.163-166
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• 2021

ICISC'20에서 발표된 경량 블록암호 PIPO는 비트 슬라이스 기법 적용으로 효율적인 구현이 되었으며, 부채널 내성을 지니기에 안전하지 않은 환경에서도 안정적으로 사용 가능한 경량 블록암호이다. 본 논문에서는 ARM 프로세서를 대상으로 PIPO의 병렬 최적 구현을 제안한다. 제안하는 구현물은 8평문, 16평문의 병렬 암호화가 가능하다. 구현에는 최적의 명령어 활용, 레지스터 내부 정렬, 로테이션 연산 최적화 기법을 사용하였다. 구현은 A10x fusion 프로세서를 대상으로 한다. 대상 프로세서상에서, 기존 레퍼런스 PIPO 코드는 64/128, 64/256 규격에서 각각 34.6 cpb, 44.7 cpb의 성능을 가지나, 제안하는 기법은 8평문 64/128, 64/256 규격에서 각각 12.0 cpb, 15.6 cpb, 16평문 64/128, 64/256 규격에서 각각 6.3 cpb, 8.1 cpb의 성능을 보여준다. 이는 기존 대비 각 규격별로 8평문 병렬 구현물은 약 65.3%, 66.4%, 16평문 병렬 구현물은 약 81.8%, 82.1% 더 좋은 성능을 보인다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.401-403
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• 2015

This paper describes an efficient hardware design of 128-bit block cipher algorithm LEA(lightweight encryption algorithm). In order to achieve area-efficient and low-power implementation, round block and key scheduler block are optimized to share hardware resources for encryption and decryption. The key scheduler register is modified to reduce clock cycles required for key scheduling, which results in improved encryption/decryption performance. FPGA synthesis results of the LEA processor show that it has 2,364 slices, and the estimated performance for the master key of 128/192/256-bit at 113 MHz clock frequency is about 181/162/109 Mbps, respectively.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.26 no.6
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• pp.1353-1360
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• 2016

We analyze the efficiency of the double-block-length hash functions, Abreast-DM, HIROSE, MDC-2, MJH, MJH-Double based on AES or LEA. We use optimized open-source code for AES, and our implemented source code for LEA. As a result, the hash functions based on LEA are generally more efficient than those, based on AES. In terms of speed, the hash function with LEA are 6%~19% faster than those with AES except for Abreast-DM. In terms of memory, the hash functions with LEA has 20~30 times more efficient than those with AES.