• Journal of information and communication convergence engineering
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• 제3권1호
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• pp.5-8
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• 2005

Dynamic cipher has the property that the key-size, the number of round, and the plaintext-size are scalable simultaneously. We present the method for designing secure Dynamic cipher against meet-in-the-middle attack and linear cryptanalysis. Also, we show that the differential cryptanalysis to Dynamic cipher is hard. In this paper we propose a new network called Dynamic network for symmetric block ciphers.

• 한국정보통신학회논문지
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• 제15권7호
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• pp.1495-1500
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• 2011

동적 암호는 키의 크기, 라운드의 수 그리고 평문의 크기가 동시에 측정될 수 있는 특성을 갖고 있다. 본 논문에서는 동적 네트워크에 기반한 대칭적인 블록 암호 알고리즘을 제안한다. 제안하는 동적 암호는 중간충돌공격과 선형 암호해독법에 대해서 안전하다. 또한 동적 암호에 대한 미분 분석이 힘든 것을 보여준다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 ITC-CSCC -2
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• pp.743-746
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• 2000

In this paper we propose a new network called Dynamic network for symmetric block ciphers. Dynamic cipher has the property that the key-size, the number of round, and the plaintext-size are scalable simultaneously We present the method for designing secure Dynamic cipher against meet-in-the-middle attack and linear cryptanalysis. Also, we show that the differential cryptanalysis to Dynamic cipher is hard.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2000년도 추계학술발표논문집 (상)
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• pp.149-152
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• 2000

Dynamic Network은 블록 크기와 키 크기, 라운드 수가 동시에 가변이며, 각 라운드에서 서브 블록과 서브 키 사이에 연산이 이루어지지 않는 대칭키 블륵 암호 알고리즘을 위한 기본구조이다. 본 논문에서는 Dynamic Network에 기반한 대칭키 블록 암호 알고리즘을 제안한다. 제안하는 Dynamic Cipher는 임의의 비트 스트링을 키로서 사용할 수 있다. 제안하는 Dynamic Cipher에 차분 분석법과 선형 분석법의 적용이 어려움을 보이고, 대칭키 블록 암호 알고리즘이 만족하여야 할 성질들에 대한 실험 결과들을 제시한다.

• 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.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제12권2호
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• pp.143-152
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• 2005

We present a new block cipher called DyC. It consists of four sets (procedures) having the different $2^2,\;2^2,\;2^4$, and $2^8$ one-to-one correspondence functions as the elements. The round key is used to determine exactly one composite function from the possible $2^{16}$ composite functions. DyC supports 8 $\times$ n bit key size, 16 $\times$ m bit block length, and n rounds. We have confirmed that DyC offers security against other well-known advanced cryptanalytic attacks including the slide attacks and interpolation attacks. In this paper, we show several properties of the key schedule of DyC by mathematical analysis.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권12호
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• pp.3398-3415
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• 2023

Internet-of-Things (IoT) is an emerging technology that interconnects millions of small devices to enable communication between the devices. It is heavily deployed across small scale to large scale industries because of its wide range of applications. These devices are very capable of transferring data over the internet including critical data in few applications. Such data is exposed to various security threats and thereby raises privacy-related concerns. Even devices can be compromised by the attacker. Modern cryptographic algorithms running on traditional machines provide authentication, confidentiality, integrity, and non-repudiation in an easy manner. IoT devices have numerous constraints related to memory, storage, processors, operating systems and power. Researchers have proposed several hardware and software implementations for addressing security attacks in lightweight encryption mechanism. Several works have made on lightweight block ciphers for improving the confidentiality by means of providing security level against cryptanalysis techniques. With the advances in the cipher breaking techniques, it is important to increase the security level to much higher. This paper, focuses on securing the critical data that is being transmitted over the internet by PRESENT using key-based dynamic S-Box. Security analysis of the proposed algorithm against other lightweight block cipher shows a significant improvement against linear and differential attacks, biclique attack and avalanche effect. A novel key-based dynamic S-Box approach for PRESENT strongly withstands cryptanalytic attacks in the IoT Network.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 1998년도 가을 학술발표논문집 Vol.25 No.2 (3)
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• pp.615-617
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• 1998

본 논문에서는 블록 암호 알고리즘을 위한 새로운 Dynamic-네트워크를 제시한다. Dynamic-네트워크 는 좋은 confusion과 diffusion 메카니즘을 제공한다. 어떠한 Dynamic-네트워크 {{{{ { 2}^{n }-비트(n >=1) }}}}길 이를 갖는 모든 평문을 입력으로 할 수 있으며, 일정 길이 이상의 모든 비트 스트링을 키로 사용할 수 있다.

• 한국컴퓨터정보학회논문지
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• 제13권4호
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• pp.169-175
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• 2008

현재의 블록 암호화 알고리즘은 암호화키 값을 변환하지 않고 설계되며, 각각의 블록의 라운드 함수들을 적용하며 암호화한다. 그러므로, 반복적인 라운드 구조의 블록암호화 기법을 위한 가장 강력한 방법들인 차분 암호 분석법 또는 선형 암호 분석법에 의해 평문이나 암호화키는 쉽게 노출된다는 취약점을 가지고 있다. 다이내믹 암호는 키의 크기, 라운드의 수, 그리고 평문의 길이가 동시에 측정될 수 있는 특성을 가지고 있다. 다이내믹 네트워크는 대칭적 블록 암호들에 대한 네트워크들 속에서 이러한 특성들을 만족시키는 독특한 네트워크이다. 우리는 중간 결과에 의한 공격, 선형 암호 분석법, 그리고 차분 암호 분석법에 대한 다이내믹 네트워크의 강력함을 분석한다. 또한, 본 논문에서 대칭적인 블록 암호를 위한 다이내믹 네트워크라 불리는 새 네트워크 방식을 제안한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권7호
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• pp.3608-3628
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• 2017

Several block cipher modes of operation have been proposed in the literature to protect sensitive information. However, different security analysis models have been presented for attacking them. The analysis indicated that most of the current modes of operation are vulnerable to several attacks such as known plaintext and chosen plaintext/cipher-text attacks. Therefore, this paper proposes a secure block cipher mode of operation to thwart such attacks. In general, the proposed mode combines one-time chain keys with each plaintext before its encryption. The challenge of the proposed mode is the generation of the chain keys. The proposed mode employs the logistic map together with a nonce to dynamically generate a unique set of chain keys for every plaintext. Utilizing the logistic map assures the dynamic behavior while employing the nonce guarantees the uniqueness of the chain keys even if the same message is encrypted again. In this way, the proposed mode called SPCBC can resist the most powerful attacks including the known plaintext and chosen plaintext/cipher-text attacks. In addition, the SPCBC mode improves encryption time performance through supporting parallelized implementation. Finally, the security analysis and experimental results demonstrate that the proposed mode is robust compared to the current modes of operation.