• Journal of the Korea Computer Industry Society
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• v.10 no.3
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• pp.105-114
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• 2009

In this paper a modified Feistel network 128 bit block cipher algorithm is proposed. The proposed algorithm has a 128, 196 or 256 bit key and it updates a selected 32 bit word from input value whole by deformed Feistel Network structure. Existing of such structural special quality is getting into block cipher algorithms and big distinction. The proposed block cipher algorithm shows much improved software speed compared with international standard block cipher algorithm AES and domestic standard block cipher algorithm SEED and ARIA. It may be utilized much in same field coming smart card that must perform in limited environment if use these special quality.

• The Journal of Society for e-Business Studies
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• v.5 no.1
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• pp.55-73
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• 2000

Recently; EC(Electronic Commerce) is increasing with high speed based on the expansion of Internet. EC which is done on the cyber space through Internet has strong point like independence from time and space. On the contrary, it also has weak point like security problem because anybody can access easily to the system due to open network attribute of Internet. Therefore, we need the solutions that protect the security problem for safe and useful EC activity. One of these solutions is the implementation of strong cipher algorithm. NC(Nonpolynomial Complete) cipher algorithm proposed in this paper is good for the security and it overcome the limit of current 64bits cipher algorithm using 128bits key length for input, output and encryption key, Moreover, it is designed for the increase of calculation complexity and probability calculation by adapting more complex design for subkey generation regarded as one of important element effected to encryption. The result of simulation by the comparison with other cipher algorithm for capacity evaluation of proposed NC cipher algorithm is that the speed of encryption and decryption is 7.63 Mbps per block and the speed of subkey generation is 2,42 μ sec per block. So, prosed NC cipher algorithm is regarded as proper level for encryption. Furthermore, speed of subkey generation shows that NC cipher algorithm has the probability used to MAC(Message Authentication Code) and block implementation of Hash function.

• Journal of Internet Computing and Services
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• v.21 no.3
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• pp.11-19
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• 2020

In this paper, a merged TEA block cipher processor which unifies Tiny Encryption Algorithm(TEA), extended Tiny Encryption Algorithm(XTEA) and corrected block TEA(XXTEA) is designed. After TEA cipher algorithm was first designed, XTEA and XXTEA cipher algorithms were designed to correct security weakness. Three types of cipher algorithm uses a 128-bit master key. The designed cipher processor can encrypt or decrypt 64-bit message block for TEA/XTEA and variable-length message blocks up to 256-bit for XXTEA. The maximum throughput for 64-bit message blocks is 137Mbps and that of 256-bit message blocks is 369Mbps. The merged TEA block cipher designed in this paper has a 16% gain on the area side compared to a lightweight LEA cipher. The cryptographic IP of this paper is applicable in security module of the mobile areas such as smart card, internet banking, and e-commerce.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.4
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• pp.1944-1956
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• 2016

The Digital Video Broadcasting-Common Scrambling Algorithm is an ETSI-designated algorithm designed for protecting MPEG-2 signal streams, and it is universally used. Its structure is a typical hybrid symmetric cipher which contains stream part and block part within a symmetric cipher, although the entropy is 64 bits, there haven't any effective cryptanalytic results up to now. This paper studies the security level of CSA against impossible differential cryptanalysis, a 20-round impossible differential for the block cipher part is proposed and a flaw in the cipher structure is revealed. When we attack the block cipher part alone, to recover 16 bits of the initial key, the data complexity of the attack is O(2^44.5), computational complexity is O(2^22.7) and memory complexity is O(2^10.5) when we attack CSA-BC reduced to 21 rounds. According to the structure flaw, an attack on CSA with block cipher part reduced to 21 rounds is proposed, the computational complexity is O(2^21.7), data complexity is O(2^43.5) and memory complexity is O(2^10.5), we can recover 8 bits of the key accordingly. Taking both the block cipher part and stream cipher part of CSA into consideration, it is currently the best result on CSA which is accessible as far as we know.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.3 no.2
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• pp.64-69
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• 2010

This paper designs the ABC(Advanced Block Cipher) algorithm which is a 64byte block encryption algorithm, improves the performance of encryption process time, and makes an key exchange using EC-DH. The ABC algorithm reduces basic memory occupation rates using the original data position exchange method which is a data swap key without S-Box, IP-Box and etc. Also, it prepares the exposure of symmetric key using the unfixed encryption(decryption) key excepting the fixed encryption(decryption) key. Therefore, the proposed ABC algorithm in this paper is a proper encryption algorithm in lower memory environment and mobile banking.

• Journal of Advanced Navigation Technology
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• v.17 no.5
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• pp.568-573
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• 2013

In this paper, we propose a differential fault analysis on symmetry structured SPN block cipher proposed in 2008. The target algorithm has the SPN structure and a symmetric structure in encryption and decryption process. To recover the 128-bit secret key of the target algorithm, this attack requires only one random byte fault and an exhaustive search of $2^8$. This is the first known cryptanalytic result on the target algorithm.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.777-779
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• 2014

The LEA(Lightweight Encryption Algorithm) is a 128-bit high-speed/lightweight block cipher algorithm developed by National Security Research Institute(NSRI) in 2012. The LEA encrypts plain text of 128-bit using cipher key of 128/192/256-bit, and produces cipher text of 128-bit, and vice versa. To reduce hardware complexity, we propose an efficient architecture which shares hardware resources for encryption and decryption in round transformation block. Hardware sharing technique for key scheduler was also devised to achieve area-efficient and low-power implementation. The designed LEA cryptographic processor was verified by using FPGA implementation.

• Journal of Korea Multimedia Society
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• v.5 no.6
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• pp.665-673
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• 2002

In this paper, we introduce cellular automata and propose a new block cipher algorithm based on cellular automata. For the evaluation of performance and security, we compare the results of the proposed algorithm with them of the standard block ciphers such as DES, Rijndael regarding on avalanche effects and processing time, and analyze the differential cryptanalysis for a reduction version of the proposed algorithm. In addition, we perform the statistical tests in FIPS PUB 140-2(Federal Information Processing Standards Publication 140-2) for the output bit sequences of proposed algorithm to guarantee the randomness property.

• Journal of KIISE:Computer Systems and Theory
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• v.30 no.3_4
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• pp.149-159
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• 2003

The need for information security increases interests on cipher algorithms recently. Especially, a large volume of data transmission over high-band communication network requires faster encryption and decryption techniques for real-time processing. It would be a good solution for this problem that we implement the cipher algorithm in forms of hardware circuits. Though some previous researches use this approach, they focus only on repeatedly executing the core part of the algorithm to minimize the hardware chip size, while most cipher algorithms are inherently parallel. In this paper, we propose a new design for the SEED block cipher algorithm developed by KISA (Korea Information Security Agency) in 1998 as Korean standard cipher algorithm. It exploits the parallelism of the algorithm basically and implements it in a pipelined fashion. We described the design in VHDL program and performed functional simulations on the program, and then found that it worked correctly. In addition, we synthesized it and verified that it could be implemented in a single FPGA chip, implying that the new design can be Practically used for the actual hardware implementation of a high-speed and high-performance cipher system.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.28 no.2
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• pp.347-355
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• 2018

Ransomware uses symmetric-key algorithm such as a block cipher to encrypt users' files illegally. If we find the traces of a block cipher algorithm in a certain program in advance, the ransomware will be detected in increased rate. The inclusion of a block cipher can consider the encryption function will be enabled potentially. This paper proposes a way to determine whether a particular program contains a block cipher. We have studied the implementation characteristics of various block ciphers, as well as the AES used by ransomware. Based on those characteristics, we are able to find what kind of block ciphers have been contained in a particular program. The methods proposed in this paper will be able to detect ransomware with high probability by complementing the previous detection methods.