• Journal of KIISE:Information Networking
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• v.29 no.6
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• pp.654-662
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• 2002

As the Internet technology becomes a major information infrastructure, an emerging problem is the tremendous increase of malicious computer intrusions. The present Intrusion Detection System (IDS) serves a useful purpose for detecting such intrusions, but the current situation requires more active response mechanism other than simple detection. This paper describes a multi-agent based tracing system against the intruders when the system is attacked. The focus of the study lies on the secure communication mechanism for the agent message communication. We have extended parameters on the KQML protocol, and apt)lied the public key encryption approach, The limitation might be the requirements of two-way authentication for every communication through the broker agent. This model ma)r not improve the efficiency, but it provides a concrete secure communication. Also this is one important factor to protect the agent and the tracing server during the tracing process.

• Journal of Internet Computing and Services
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• v.20 no.6
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• pp.119-127
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• 2019

This paper proposes a new authentication model to solve the problem of personal information takeover and personal information theft by service providers using centralized servers for user authentication and management of personal information. The centralization issue is resolved by providing user authentication and information storage space through a decentralize platform, blockchain, and ensuring confidentiality of information through user-specific symmetric key encryption. The proposed model was implemented using the public-blockchain Ethereum and the web-based wallet extension MetaMask, and users access the Ethereum main network through the MetaMask on their browser and store their encrypted personal information in the Smart Contract. In the future, users will provide their personal information to the service provider through their Ethereum Account for the use of the new service, which will provide user authentication and personal information without subscription or a new authentication process. Service providers can reduce the costs of storing personal information and separate authentication methods, and prevent problems caused by personal information leakage.

• 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.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.14 no.6
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• pp.31-45
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• 2004

Public Key Infrastructure(PKI) provides a strong authentication. Privilege Management Infrastructure(PMI) as a new technology can provide user's attribute information. The main function of PMI is to give more specified authority and role to user. To authenticate net and role, we have used digital signature. Role Based Access Control(RBAC) is implemented by digital signature. RBAC provides some flexibility for security management. NEIS(National Education Information System) can not always provide satisfied quality of security management. The main idea of the proposed RNEIS(Roll Based NEIS) is that user's role is stored in AC, access control decisions are driven by authentication policy and role. Security manager enables user to refer to the role stored in user's AC, admits access control and suggests DB encryption by digital signature.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.34 no.2
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• pp.157-166
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• 2024

Probability of decryption failure of a public key cryptography based on LWE(learning with errors) is determined by its architecture and parameter settings. Since large decryption failure probability leads to attacks[1] on scheme as well as degradation of performance, TiGER[2], a Ring-LWE(R)-based KEM proposed for the first round of KpqC, tried to reduce the decryption failure probability by using error correction code Xef and D2 encoding method. However, D'Anvers et al. has shown that the commonly assumed independence of each bit error is not established since in the case of an encryption scheme based on Ring-LWE(R) using an error correction code, there is error dependency which is not negligible[3]. In this paper, since TiGER does not consider the error dependency, we calcualte the decryption failure probability of TiGER by considering the error dependency. In addition, we found that the bit error probability is incorrectly calculated in TiGER, so we present the correct calculation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.3
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• pp.1428-1438
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• 2013

Services take place in Internet environment, a formation of the trust relationship between user and service provider for services. Different authentication schemes such as using Certificate of Public Key Infrastructure authentication and using ID/PW for a simple user authentication have been proposed for trust relationship. In addition, in the case of electronic financial transactions, transaction integrity and non-repudiation features are provided. These services are provided in Internet environment, use various measures to ensure service safety. However, it was difficult to prevent attacks using existing security technology because of emergence of MITB attack that manipulate the memory area of the Web browser and social engineering attacks such as phishing/pharming, requires application of new security technologies became. In this paper, we propose a concept of smart secure-pad, and utilize it safely formed a trust relationship between user and service provider, a model has been proposed to ensure safety of data transmission. Proposed model's security evaluation results show security against to MITB attack and phishing/pharming that can't be prevent attack using existing security technology. In addition, service provider can easily apply the model in safe environment can provide Internet service using provided representative services applying the proposed model.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.12 no.2
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• pp.21-34
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• 2002

In this paper we propos a new hardware architecture of modular exponentiation using a division chain method which has been proposed in (2). Modular exponentiation using the division chain is performed by receding an exponent E as a mixed form of multiplication and addition with divisors d=2 or $d=2^I +1$ and respective remainders r. This calculates the modular exponentiation in about $1.4log_2$E multiplications on average which is much less iterations than $2log_2$E of conventional Binary Method. We designed a linear systolic array multiplier with pipelining and used a horizontal projection on its data dependence graph. So, for k-bit key, two k-bit data frames can be inputted simultaneously and two modular multipliers, each consisting of k/2+3 PE(Processing Element)s, can operate in parallel to accomplish 100% throughput. We propose a new encoding scheme to represent divisors and remainders of the division chain to keep regularity of the data path. When it is synthesized to ASIC using Samsung 0.5 um CMOS standard cell library, the critical path delay is 4.24ns, and resulting performance is estimated to be abort 140 Kbps for a 1024-bit data frame at 200Mhz clock In decryption process, the speed can be enhanced to 560kbps by using CRT(Chinese Remainder Theorem). Futhermore, to satisfy real time requirements we can choose small public exponent E, such as 3,17 or $2^{16} +1$, in encryption and verification process. in which case the performance can reach 7.3Mbps.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.21 no.1
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• pp.15-26
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• 2011

The development of IT technology and information communication networks activated to online financial transactions; the users were able to get a variety of financial services. However, unlike the positive effect that occurred on 7 July 2009 DDoS(Distribute Denial of Service) attacks, such as damaging to the user, which was caused negative effects. Authentication technology(OTP) is used to online financial transaction, which should be reviewed to safety with various points because the unpredictable attacks can bypass the authentication procedure such as phishing sites, which is occurred. Thus, this paper proposes mobile OTP(One Time Password) Mechanism, which is based on PKI to improve the safety of OTP authentication. The proposed Mechanism is operated based on PKI; the secret is transmitted safely through signatures and public key encryption of the user and the authentication server. The users do not input in the web site, but the generated OTP is directly transmitted to the authentication server. Therefore, it is improvement of the availability of the user and the resolved problem is exposed from the citibank phishing site(USA) in 2006.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.5
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• pp.3-16
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• 2008

A Wireless Sensor Network (WSN for short) is a wireless network consisting of distributed small devices which are called sensor nodes or motes. Recently, there has been an extensive research on WSN and also on its security. For secure storage and secure transmission of the sensed information, sensor nodes should be equipped with cryptographic algorithms. Moreover, these algorithms should be efficiently implemented since sensor nodes are highly resource-constrained devices. There are already some existing algorithms applicable to sensor nodes, including public key ciphers such as TinyECC and standard block ciphers such as AES. Stream ciphers, however, are still to be analyzed, since they were only recently standardized in the eSTREAM project. In this paper, we implement over the MicaZ platform nine software-based stream ciphers out of the ten in the second and final phases of the eSTREAM project, and we evaluate their performance. Especially, we apply several optimization techniques to six ciphers including SOSEMANUK, Salsa20 and Rabbit, which have survived after the final phase of the eSTREAM project. We also present the implementation results of hardware-oriented stream ciphers and AES-CFB fur reference. According to our experiment, the encryption speeds of these software-based stream ciphers are in the range of 31-406Kbps, thus most of these ciphers are fairly acceptable fur sensor nodes. In particular, the survivors, SOSEMANUK, Salsa20 and Rabbit, show the throughputs of 406Kbps, 176Kbps and 121Kbps using 70KB, 14KB and 22KB of ROM and 2811B, 799B and 755B of RAM, respectively. From the viewpoint of encryption speed, the performances of these ciphers are much better than that of the software-based AES, which shows the speed of 106Kbps.