• The KIPS Transactions:PartC
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• v.14C no.6
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• pp.463-470
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• 2007

Revocation is one of the main difficulties faced in implementing Public Key Infrastructures(PHs). Boneh, Ding and Tsudik first introduced a mediated cryptography for obtaining immediate revocation of RSA keys used in PKIs. Their method is based on the idea that each user's private key can be split into two random shares, one of which is given to the user and the other to an online security mediator(SEM). Thus any signature or decryption must be performed as a cooperation between a user and his/her associated SEM and revocation is achieved by instructing the mediator SEM to stop cooperating the user. Recently, Libert and Quisquater showed that the fast revocation method using a SEcurity Mediator(SEM) in a mRSA can be applied to the Boneh-Franklin identify based encryption and GDH signature schemes. In this paper we propose a mediated identity based signature(mIBS) with batch verification which apply the SEM architecture to an identity based signature. Libert's GDH siganture scheme is not forward secure even though forward security is an important and desirable feature for signature schemes. We propose an efficient key udating mediated signature scheme, mKUS based on mIBS and analyze its security and efficiency.

• Journal of the Korea Society for Simulation
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• v.31 no.3
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• pp.35-44
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• 2022

In this study, we analyze and forecast quantum computer technology trends. Previous research has been mainly focused on application fields centered on technology for quantum computer technology trends analysis. Therefore, this paper analyzes important quantum computer technologies and performs future signal detection and prediction, for a more market driven technical analysis and prediction. As analyzing words used in news articles to identify rapidly changing market changes and public interest. This paper extends conference presentation of Cha & Chang (2022). The research is conducted by collecting domestic news articles from 2019 to 2021. First, we organize the main keywords through text mining. Next, we explore future quantum computer technologies through analysis of Term Frequency - Inverse Document Frequency(TF-IDF), Key Issue Map(KIM), and Key Emergence Map (KEM). Finally, the relationship between future technologies and supply and demand is identified through random forests, decision trees, and correlation analysis. As results of the study, the interest in artificial intelligence was the highest in frequency analysis, keyword diffusion and visibility analysis. In terms of cyber-security, the rate of mention in news articles is getting overwhelmingly higher than that of other technologies. Quantum communication, resistant cryptography, and augmented reality also showed a high rate of increase in interest. These results show that the expectation is high for applying trend technology in the market. The results of this study can be applied to identifying areas of interest in the quantum computer market and establishing a response system related to technology investment.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.8
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• pp.1443-1448
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• 2006

As computers and networks become popular, distributing information on the Internet is common in our daily life. In the past, e-mail has been the primary choice of exchanging information but messengers are gaining popularity abroad and domestically because of their nature of getting immediate responses. Information leakage by invasion that is enemy of evil in communication of communications division Server and Agent between each agents that become burden of communication for effective administration of data for most of existing messenger is becoming an issue. In this paper, we design a secure messenger system that could be obtained maximum security. It use ECC based on ElGamal methodology using PKI for secure communication. For the message encryption and decryption between the same group non, each group is kept distinct by drawing an elliptic curve and an arbitrary point is chosen on the curve.

• Journal of KIISE:Information Networking
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• v.30 no.2
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• pp.199-206
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• 2003

one of the representative micropayment protocols. The original PayWord system is designed for a user who generates paywords by performing hash chain operation for payment to an only designated vendor. In other words, a user has to create new hash chain values in order to establish commercial transactions with different vendors on the Internet. Therefore, we suggest an efficient scheme that is able to deal with business to different vendors by using only one hash chain operation to supplement this drawback. In this proposed system, a broker creates a new series of hash chain values along with a certificate for the user's certificate request. This certificate is signed by a broker to give authority enabling a user to generate hash chain values. hew hash chain values generated by a broker provide means to a user to do business with multiple vendors.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.4
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• pp.691-699
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• 2009

Recently, the ERO protocol has been adopted as a standard to protect the routing optimization mode introduced by MIPv6. This protocol uses the public key cryptography and the early binding update method to improve the Return Routeability protocol while optimizing both security and performance. On the other hand, though various security approaches including the ERO protocol have been proposed for MIPv6, they lack formal verification. Especially, to our best knowledge, there is no formal analysis on the ERO protocol. In order to provide a good example for formal analysis on MIPv6 security protocols, this paper verifies the correctness of the ERO protocol through BAN-logic. For this goal, BAN-logic is extended to consider the address tests on the mobile nodes's CoA and HoA. It is expected that the analysis presented in this paper will be useful for the formal verifications on the security protocols related to MIPv6.

• Journal of IKEEE
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• v.23 no.4
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• pp.1321-1327
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• 2019

This paper describes an efficient hardware implementation of modular square root (MSQR) computation over GF(p), which is the operation needed to map plaintext messages to points on elliptic curves for elliptic curve (EC)-ElGamal public-key encryption. Our method supports five sizes of elliptic curves over GF(p) defined by the National Institute of Standards and Technology (NIST) standard. For the Koblitz curves and the pseudorandom curves with 192-bit, 256-bit, 384-bit and 521-bit, the Euler's Criterion based on the characteristic of the modulo values was applied. For the elliptic curves with 224-bit, the Tonelli-Shanks algorithm was simplified and applied to compute MSQR. The proposed method was implemented using the finite field arithmetic circuit with 32-bit datapath and memory block of elliptic curve cryptography (ECC) processor, and its hardware operation was verified by implementing it on the Virtex-5 field programmable gate array (FPGA) device. When the implemented circuit operates with a 50 MHz clock, the computation of MSQR takes about 18 ms for 224-bit pseudorandom curves and about 4 ms for 256-bit Koblitz curves.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.724-727
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• 2008

Studies on binary adder have been variously developed. According to those studies of critical worst delay and mean delay time of asynchronous binary adders, carry select adders (CSA) based on hybrid structure showed 17% better performance than ripple carry adders (RCA) in 32 bit asynchronous processors, and 23% better than in 64 bit microprocessor implemented. In the complicated signal processing systems such as RSA, it is essential to optimize the performance of binary adders which play fundamental roles. The researches which have been studied so far were subject mostly to addition algorithms or adder structures. In this study, we analyzed and designed adders in an asp;ect of synthesis method. We divided the ways of implementing adders into groups, each of which was synthesized with different synthesis options. Also, we analyzed the variously implemented adders to evaluate the performance and area so that we can propose a different approach of designing optimal binary adders.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.9
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• pp.1257-1263
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• 2018

Secure authentication technology is a fundamental building block for secure services for Internet of Things devices. Particularly, the multiplication operation is a core operation of public key cryptography, such as RSA, ECC, and SIDH. However, modern low-power processor, namely ARM Cortex-M3 processor, is not secure enough for practical usages, since it executes the multiplication operation in variable-time depending on the input length. When the execution is performed in variable-time, the attacker can extract the password from the measured timing. In order to resolve this issue, recent work presented constant-time solution for multiplication operation. However, the implementation still missed various speed-optimization techniques. In this paper, we analyze previous multiplication methods over ARM Cortex-M3 and provide optimized implementations to accelerate the speed-performance further. The proposed method successfully accelerates the execution-time by up-to 25.7% than previous works.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.7
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• pp.1493-1500
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• 2004

Today's Commercial security server system which provide secrecy, integrity and availability may still be vulnerable to denial-of-service attacks. Authentication system whith use a public key cryptography and process RSA encryption is relatively slow and the slowness has become a major security threat specifically in service flooding attacks caused by authentication requests. The service flooding attacks render the server incapable of providing its service to legitimitive clients. Therefore the importance of implementing systems that prevent denial of service attacks and provide service to legitimitive users cannot be overemphasized. In this paper, we propose a puzzle protocol which applies to authentication model. our gradually strengthening authentication model improves the availability and continuity of services and prevent denial of service attacks and we implement flooding of service tolerance system to verify the efficiency of our model. This system is expected to be ensure in the promotion of reliability.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.2C
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• pp.208-218
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• 2008

We are sure that RFID system should be a widely used automatic identification system because of its various advantages and applications. However, many people know that invasions of privacy in RFID system is still critical problem that makes it difficult to be used. Many works for solving this problem have focused on light-weight cryptographic functioning in the RFID tag. An agent scheme is another approach that an agent device controls communications between the tag and the reader for protecting privacy. Generally an agent device has strong security modules and enough capability to process high-level cryptographic protocols and can guarantees consumer privacy. In this paper, we present an enhanced mobile agent for RFID privacy protection. In enhanced MARP, we modified some phases of the original MARP to reduce the probability of successful eavesdropping and to reduce the number of tag's protocol participation. And back-end server can authenticate mobile agents more easily using public key cryptography in this scheme. It guarantees not only privacy protection but also preventing forgery.