• Journal of Korea Society of Digital Industry and Information Management
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• v.13 no.4
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• pp.99-106
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• 2017

With the advent of virtual money such as bit coins, interest in the block chain is increasing. Block Chain is a technology that supports Distributed Ledger and is a versatile technology applicable to various fields. Currently, the block chain is conducting research for various applications such as virtual money, trade finance, marketplace, power market, image contents service, and IoT. The technologies that make up the block chain are smart contract, digital signature/hash function and consensus algorithm. And these technologies operate on P2P networks. In this paper, we have studied e-mail system based on the ethereum which is one of the block chain based technologies. Most legacy mail systems use SMTP and the POP3/IMAP protocol to send and receive e-mail, and e-mail use S/MIME to protect the e-mail. However, S/MIME is vulnerable to DDoS attacks because it is configured centrally. And it also does not provide non-repudiation of mail reception. To overcome these weaknesses, we proposed an e-mail system model based on ethereum. The proposed model is able to cope with DDoS attack and forgery prevention by using block chain based technology, and reliable recording and management among block chain participants are provided, so that it is possible to provide a non-repudiation function of e-mail transmission and reception.

• Journal of the Korea Society of Computer and Information
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• v.16 no.2
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• pp.183-191
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• 2011

Recently Wang-Li proposed the remote user authentication scheme using smart cards. But the proposed scheme has not been satisfied security requirements considering in the user authentication scheme using the password based smart card. In this paper, we described the Wang-Li and Yoon et al.'s authentication scheme simply, and we prove that the Wang-Li's scheme is vulnerable to a password guessing attack and impersonation attack in case that the attacker steals the user's smart card and extracts the information in the smart card. Accordingly, we propose the improved user authentication scheme based on the hash function and generalized ElGamal signature scheme that can withstand many possible attacks including a password guessing attack, impersonation attack and replay attack, and that can offer the function of forward secrecy. The result of comparative analysis, the our proposed scheme is much more secure and efficient than the Wang-Li and Yoon et al.'s scheme.

• KIPS Transactions on Computer and Communication Systems
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• v.2 no.11
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• pp.495-502
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• 2013

In this paper, we present an anonymous authentication and location assurance protocol for secure location-aware services over vehicular ad hoc networks (VANETs). In other to achieve our goal, we propose the notion of a location-aware signing key so as to strongly bind geographic location information to cryptographic function while providing conditional privacy preservation which is a desirable property for secure vehicular communications. Furthermore, the proposed protocol provides an efficient procedure based on hash chain technique for revocation checking to effectively alleviate communication and computational costs on vehicles in VANETs. Finally, we demonstrate comprehensive analysis to confirm the fulfillment of the security objectives, and the efficiency and effectiveness of the proposed protocol.

• Journal of Digital Convergence
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• v.12 no.4
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• pp.259-264
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• 2014

Body insertion due to the recent development of sensor technology, the device is attached patients to receive medical services from anywhere, anytime environment is changing. Body insertion devices for the hospital, the patient's vital information attached personnel (doctors, nurses, pharmacists, etc.) to pass, however, when a problem occurs, a patient's information to a third party that can be exploited easily exposed. In this paper, we proposed signature authentication protocols mandate based on the patient's power of attorney from the center of the u-Healthcare services, hospital officials FormHelper third party disguised as a patient, the hospital patient information easily obtained from the officials to prevent. The proposed protocol, the patient's sensitive information to a third party, do not expose the patient's sensitive information to the random number generated by the u-Healthcare service centers and patients hash signature key to encrypt sensitive information of patients. From third parties to maintain synchronization between the patients and the hospital personnel in order to prevent patient information from being exploited illegally by the patient's vital information leakage can be prevented.

• The KIPS Transactions:PartC
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• v.11C no.7 s.96
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• pp.981-992
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• 2004

The established NEIS has a lot of problems in the management of security. It does not realize access control in following authority because it only uses PKI certification in user certification and the use of central concentration DBMS and plain text are increased hacking possibility in NEIS. So, This paper suggests a new NEIS for the secure management of data and authority certification. First, we suggest the approached authority in AC pf PMI and user certification in following the role, RBAC. Second, we realize DB encryption plan by digital signature for the purpose of preventig DB hacking. Third, we suggest SQL counterfeit prevention by one-way hash function and safe data transmission per-formed DB encryption by digital signature.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.7
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• pp.2532-2553
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• 2014

In Asiacrypt 2003, Al-Riyami and Paterson proposed the notion of certificateless cryptography, a technique to remove key escrow from traditional identity-based cryptography as well as circumvent the certificate management problem of traditional public key cryptography. Subsequently much research has been done in the realm of certificateless encryption and signature schemes, but little to no work has been done for the identification primitive until 2013 when Chin et al. rigorously defined certificateless identification and proposed a concrete scheme. However Chin et al.'s scheme was proven in the random oracle model and Canetti et al. has shown that certain schemes provable secure in the random oracle model can be insecure when random oracles are replaced with actual hash functions. Therefore while having a proof in the random oracle model is better than having no proof at all, a scheme to be proven in the standard model would provide stronger security guarantees. In this paper, we propose the first certificateless identification scheme that is both efficient and show our proof of security in the standard model, that is without having to assume random oracles exist.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.12
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• pp.5895-5901
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• 2011

This paper shows that a scheme provided by An[7] is not enough to satisfy security requirements for a user certification using a password-based smart card. In order to compensate this weakness, this study provides an improved user scheme with a hash function and ElGamal signature. This new scheme has some advantages protecting password guessing attack, masquerade, and replay attack as well as providing forward secrecy. Compared to An's certification scheme, this scheme suggests that the effect of computational complexity is similar but the efficiency of safety is better.

• Convergence Security Journal
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• v.15 no.5
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• pp.3-8
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• 2015

Most mobile cloud computing system use public key cryptography to provide data security and mutual authentication. A variant of traditional public key technologies called Identity-Based Cryptography(IBC) has recently received considerable attention. The certificate-free approach of IBC may well match the dynamic qualities of cloud environment. But, there is a need for a lightweight secure framework that provides security with minimum processing overhead on mobile devices. In this paper, we propose to use hierarchical ID-Based Encryption in mobile cloud computing. It is suitable for a mobile network since it can reduce the workload of root Public Key Generators by delegating the privilege of user authentication and private key generation. The Identity-Based Encryption and Identity-Based Signature are also proposed and an ID-Based Authentication scheme is presented to secure data processing. The proposed scheme is designed by one-way hash functions and XOR operations, thus has low computation costs for mobile users.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.28 no.1
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• pp.73-83
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• 2018

There has been increasing interest from NIST and other companies in studying post-quantum cryptography in order to resist against quantum computers. Multivariate polynomial based, code based, lattice based, hash based digital signature, and isogeny based cryptosystems are one of the main categories in post quantum cryptography. Among these categories, isogeny based cryptosystem is known to have shortest key length. In this paper, we implemented Supersingular Isogeny Diffie-Hellman (SIDH) protocol efficiently on low-end mobile device. Considering the device's specification, we select supersingular curve on 523 bit prime field, and generate efficient isogeny computation tree. Our implementation of SIDH module is targeted for 32bit environment.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.2
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• pp.15-26
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• 2021

Recently, as the introduction of cloud, mobile, and IoT has become active, there is a growing need for technology development that can supplement the limitations of traditional security solutions based on fixed perimeters such as firewalls and Network Access Control (NAC). In response to this, SDP (Software Defined Perimeter) has recently emerged as a new base technology. Unlike existing security technologies, SDP can sets security boundaries (install Gateway S/W) regardless of the location of the protected resources (servers, IoT gateways, etc.) and neutralize most of the network-based hacking attacks that are becoming increasingly sofiscated. In particular, SDP is regarded as a security technology suitable for the cloud and IoT fields. In this study, a new access control system was proposed by combining SDP and hash tree-based large-scale data high-speed signature technology. Through the process authentication function using large-scale data high-speed signature technology, it prevents the threat of unknown malware intruding into the endpoint in advance, and implements a kernel-level security technology that makes it impossible for user-level attacks during the backup and recovery of major data. As a result, endpoint security, which is a weak part of SDP, has been strengthened. The proposed system was developed as a prototype, and the performance test was completed through a test of an authorized testing agency (TTA V&V Test). The SDP-based access control solution is a technology with high potential that can be used in smart car security.