• Proceedings of the IEEK Conference
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• 2002.06b
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• pp.125-128
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• 2002

This paper designed a cipher process, which used SEED-Algorithm that is totally domestic technique. This cipher processor is implemented by using SEED-cipher-Algorithm and pipeline scheduling architecture. The cipher is 16-round Feistel architecture but we show just 16-round Feistel architecture for brevity in this thesis. Of course, we can get the result of the 16-round processing by addition of control part simply. Furthermore, it has pipelined architecture, so the speed of cipher process is the faster than others when we performed a cipher a lot of data. The schedule-function can performed the two-cipher process simultaneously, such as using two-cipher processors.

• 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.

• 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.

• KIPS Transactions on Computer and Communication Systems
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• v.4 no.3
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• pp.105-108
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• 2015

In this paper, we propose a differential fault analysis on symmetric SPN block cipher with bitslice involution S-box in 2011. The target block cipher was designed using AES block cipher and has advantage about restricted hardware and software environment using the same structure in encryption and decryption. Therefore, the target block cipher must be secure for the side-channel attacks. However, to recover the 128-bit secret key of the targer block cipher, this attack requires only one random byte fault and an exhausted search of $2^8$. This is the first known cryptanalytic result on the target block cipher.

• The KIPS Transactions:PartD
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• v.13D no.3 s.106
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• pp.437-444
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• 2006

A chaos cipher system that focuses on the stream cipher system has a demerit that the longer the text is, the slower the speed of the encryption and description and the transmission and reception. On this study, we designed the cipher web mail system showing much better capabilities than the existing web mail system as the text is longer. In the embodiment of the cipher web mail system, we developed the key stream, the encryption and description of the text and the inside and outside mail viewer and so on. After the efficiency test, it was valued high in the respect of the speed of the encryption and description and the transmission and reception. And it made up for the defect of the stream cipher system. We expect that we can use it through the persistent applied study in the server system security, the file security, the security of the internet information, the protection of the e-commerce system information and other fields based on the cipher technique as the wide use cipher system that can replace the block cipher system.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.827-828
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• 2012

WG-7 is a stream cipher based on WG Stream Cipher and is designed by Y. Luo, Q. Chai, G. Gong, and X. Lai in 2010. This cipher is designed to implement in low cost and lightweight application such as RFID tags. In this paper, we survey and compare cryptographic module such as stream and block cipher. We can estimate security performance suitable to system.

• Journal of information and communication convergence engineering
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• v.3 no.1
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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.

• The KIPS Transactions:PartC
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• v.15C no.5
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• pp.359-366
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• 2008

As the use of Internet and information communication technology is being generalized, the SSL protocol is essential in Internet because the important data should be transferred securely. While the SSL protocol is designed to defend from active attack such as message forgery and message alteration, the cipher suite setting can be easily modified. If the attacker draw on a malfunction of the client system and modify the cipher suite setting to the symmetric key algorithm which has short key length, he should eavesdrop and cryptanalysis the encrypt data. In this paper, we examine the domestic web site whether they generate the security session through the symmetric key algorithm which has short key length and propose the solution of the cipher suite setting problem.

• Journal of Information Processing Systems
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• v.11 no.2
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• pp.266-279
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• 2015

In this paper, we propose a novel block cipher mode of operation, which is known as the counter chain (CC) mode. The proposed CC mode integrates the cipher block chaining (CBC) block cipher mode of operation with the counter (CTR) mode in a consistent fashion. In the CC mode, the confidentiality and authenticity of data are assured by the CBC mode, while speed is achieved through the CTR mode. The proposed mode of operation overcomes the parallelization deficiency of the CBC mode and the chaining dependency of the counter mode. Experimental results indicate that the proposed CC mode achieves the encryption speed of the CTR mode, which is exceptionally faster than the encryption speed of the CBC mode. Moreover, our proposed CC mode provides better security over the CBC mode. In summary, the proposed CC block cipher mode of operation takes the advantages of both the Counter mode and the CBC mode, while avoiding their shortcomings.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.7
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• pp.1495-1500
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• 2011

Dynamic cipher has the property that the key-size, the number of round, and the plain text-size are scalable simultaneously. In this paper we propose the block cipher algorithm which is symmetrical in the dynamic network. We present the method for designing secure Dynamic cipher against meet-in-the-middle attack and linear crytanalysis. Also, we show that the differential cryptanalysis to Dynamic cipher is hard.