• Annual Conference of KIPS
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• 2006.05a
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• pp.955-958
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• 2006

초고속인터넷이 널리 보급되면서 최근 메신저 서비스(Messenger Service)를 이용하는 사용자가 폭발적으로 증가하고, 해킹 기술의 발달로 인하여 메신저를 통하여 전달되는 메시지들이 악의의 사용자에게 쉽게 노출될 수 있는 가증서도 커지고 있다. 본 논문에서는 인스턴트 메신저의 안전한 통신을 위해 인증서를 이용한 인스턴트 메신저 프로토콜에 대해 설계하였다. 또한 메신저 서비스에서의 메시지 보안을 구현함에 있어서 공개키 암호 알고리즘의 연산수행시간을 단축하기 위해 ElGamal 방식의 ECC(Elliptic Curve Cryptography) 알고리즘을 사용하고, 사용자 그룹 단위의 암호화를 위해 그룹별로 타원곡선과 그 위에 있는 임의의 점을 선택하여 다른 그룹과 구별하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.2
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• pp.328-332
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• 2006

Efficient finite field operation in the elliptic curve (EC) public key cryptography algorithm, which attracts much of latest issues in the applications in information security, is very important. Traditional serial finite multipliers root from Mastrovito's serial multiplication architecture. In this paper, we adopt the polynomial basis and propose a new finite field multiplier, inducing numerical expressions which can be applied to exhibit 3 times as much performance as the Mastrovito's. We described the proposed multiplier with HDL to verify and evaluate as a proper hardware IP. HDL-implemented serial GF (Galois field) multiplier showed 3 times as fast speed as the traditional serial multiplier's adding only partial-sum block in the hardware. So far, there have been grossly 3 types of studies on GF($2^m$) multiplier architecture, such as serial multiplication, array multiplication, and hybrid multiplication. In this paper, we propose a novel approach on developing serial multiplier architecture based on Mastrovito's, by modifying the numerical formula of the polynomial-basis serial multiplication. The proposed multiplier architecture was described and implemented in HDL so that the novel architecture was simulated and verified in the level of hardware as well as software.

• Journal of Internet Computing and Services
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• v.13 no.2
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• pp.59-71
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• 2012

PKI-based public key scheme is outstanding in terms of authenticity and privacy. Nevertheless its application brings big burden due to the certificate/key management. It is difficult to apply it to limited computing devices in WSN because of its high encryption complexity. The Bilinear Pairing emerged from the original IBE to eliminate the certificate, is a future significant cryptosystem as based on the DDH(Decisional DH) algorithm which is significant in terms of computation and secure enough for authentication, as well as secure and faster. The practical EC Weil Pairing presents that its encryption algorithm is simple and it satisfies IND/NM security constraints against CCA. The Random Oracle Model based IBE PKG is appropriate to the structure of our target system with one secret file server in the operational perspective. Our work proposes modification of the Weil Pairing as proper to the closed network for secret file distribution[2]. First we proposed the improved one computing both encryption and message/user authentication as fast as O(DES) level, in which our scheme satisfies privacy, authenticity and integrity. Secondly as using the public key ID as effective as PKI, our improved IBE variant reduces the key exposure risk.

• Proceedings of the Korean Information Science Society Conference
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• 2001.10a
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• pp.700-702
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• 2001

As computers and networks become popular, distributing information on the Interment is common in our daily life. Also, the explosion of the Internet, of wireless digital communication and data exchange on Internet has rapidly changed the way we connect with other people. But secure mall is gamins popularity abroad and domestically because of their nature of prodding security. That is. it has been used a variety of fields such as general mail and e-mail for advertisement But, As the data transmitted on network can be easily opened or forged with simple operations. Most of existing e-mall system don't have any security on the transmitted information. Thus, security mail system need to provide security including message encryption, content integrity, message origin authentication, and non-repudiation. In this paper, we design implement secure mall system with non-repudiation service and encryption capability to provide services for certification of delivery and certification of content as well as the basic security services.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.9 no.1
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• pp.103-114
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• 1999

Recently, various prototypes for electronic commerce are realized and its related researches are active under the present condition which it is increasing for the reality of its extended applications. First of all, actual demands are increasing for more secure and efficient electronic payment systems. Electronic cash, one of the Electronic payment systems, must have several properties like real money. Blind signature scheme by D. Chaum stands for the methods of obtaining privacy. In this paper, we propose a method for obtaining the blind signature based on the Elliptic Curve Cryptosystems, where the crytosystems are known as solving some problems of conventional crytosystems in views of computation time and key space. Also, we present a method for the divisibility of the electronic cash using our proposal by re-signing spare cash. Thus applying the proposed method, we can develop an efficient electronic payment systems.

• Journal of KIISE
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• v.44 no.3
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• pp.323-331
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• 2017

Due to the recent developments of various smart devices, U-healthcare services using these appliances has increased. However, the security of U-healthcare services is a very important issue since healthcare services contain highly sensitive and private personal health information. In order to handle the security issues, the functionality of encrypting medical information must be provided, and an encryption key exchange method is necessary. In this paper, we propose a key exchange protocol by utilizing smart devices for secure U-healthcare services. The proposed protocol has been designed based on the elliptic curve based public key cryptography, providing high level security for smart devices by using short keys. Moreover, in order to strengthen user authentication and security, a smart watch is used as a complementary device, whenever the key exchange protocol is performed.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.13 no.3
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• pp.57-64
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• 2003

Recently, it has been shown that cryptographic devices such as smart cards are vulnerable to power attacks. In this paper, by mixing the randomization concept and the folding in half for secret scalar integer on ECCs, we propose an efficient and fast scalar multiplication algorithm to resist against simple power analysis(SPA) and differential power analysis(DPA) attacks. Our proposed algorithm as a countermeasure against SPA and DPA is estimated as a 33% speedup compared to the binary scalar multiplication.

• Journal of Korea Multimedia Society
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• v.14 no.6
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• pp.785-793
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• 2011

Since then, with the advance of computing environment, various Internet services are emerging and the importance of user authentication technology is increasing for verifying users authorized to use such services. Along with the advance of authentication technology, research is being made actively on one time password, which is used once in a session and then discarded. In existing one time passwords, however, the values of one time passwords in a created table are stored in serial order, and therefore, if the seed value and the number of one time passwords used are disclosed, one may infer the value of the one time password to be used next. What is more, one time passwords of the S/Key type have the problem that the number of uses is fixed. In this paper, We analysis the existing one time password. Also, We propose one time password methods using elliptic curve cryptography scheme and using enhanced randomness with time value.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.26 no.5
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• pp.1099-1103
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• 2016

The user's secret key can be retrieved by the leakage informations of power consumption occurred during the execution of scalar multiplication for elliptic curve cryptographic algorithm which can be embedded on a security device. Recently, a carry random recoding method is proposed to prevent simple power and differential power analysis attack by recoding the secret key. In this paper, we show that this recoding method is still vulnerable to the differential power analysis attack due to the limitation of the size of carry bits, which is a different from the original claim.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.3 s.357
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• pp.35-42
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• 2007

The finite-field division can be applied to the elliptic curve cryptosystems. However, an efficient algorithm and the hardware design are required since the finite-field division takes much time to compute. In this paper, we propose a radix-4 systolic divider on $GF(2^m)$ with comparative area and performance. The algorithm of the proposed divide, is mathematically developed and new counter structure is proposed to map on low-cost systolic cells, so that the proposed systolic architecture is suitable for YLSI design. Compared to the bit-parallel, bit-serial and digit-serial dividers, the proposed divider has relatively effective high performance and low cost. We design and synthesis $GF(2^{193})$ finite-field divider using Dongbuanam $0.18{\mu}m$ standard cell library and the maximum clock frequency is 400MHz.