• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.6
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• pp.1251-1259
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• 2017

One-time password has been proposed for the purpose of addressing the security problems of the simple password system: fixed passwords and pre-shared passwords. Since it employs the consecutive hash values after a root hash value is registered at the server, the security weakness of the fixed passwords has been addressed. However, it has a shortcoming of re-registering a new root hash value when the previous hash chain's hash values are exhausted. Even though several one-time password systems not requiring re-registration have been proposed, they all have several problems in terms of constraint conditions and efficiency. In this paper, we propose the one - time password scheme based on a hash chain that generates one - time passwords using only two cryptographic hash functions at each authentication and satisfies the existing constraints without re-registration, Security requirements and efficiency.

• Journal of KIISE:Information Networking
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• v.30 no.2
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• pp.207-221
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• 2003

A hash chain is highly efficient, attractive structure to use in electronic cash. Previous systems using hash chain were, however, either credit-based vendor-specific cash or debit-based general-purpose cash which lacks efficiency due to double spending problem. In this paper, we propose a new divisible cash system using hash chain. This newly proposed cash is general-purpose, debit-based, anonymous, and offline. The efficiency of the system results from its capacity to pay variable amounts with no additional costs. A client always performs a single blind signature in the withdrawal phase, independent of the length of the chain. During payment, a client performs a single challenge-and-response or generates a single signature, independent of the amount paid. This system provides a new refund mechanism, which uses a refund ticket, that allows clients to refund the unspent part of the chain without revealing any connection to the spent part.

• Journal of Korea Society of Digital Industry and Information Management
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• v.14 no.3
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• pp.69-75
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• 2018

Recently, various convergence technologies are attracting attention due to the block chain innovation technology in the M2M environment. Although the block-chain-based technology is known to be secure in its own right, there are various problems such as security and weight reduction in various M2M environments connected with this. In this paper, we propose a new lightweight method for the hash tree generation of block chains to solve the lightweight problem. It is designed considering extensibility without affecting the existing block chain. Performance analysis shows that the computation performance increases with decreasing the existing hash length.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.3
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• pp.560-566
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• 2009

A low-power Radio Frequency Identification (RFID) system is an auto-identification technology that reads and writes an information of things without physical contacts using radio frequency. It is unescapable against unlawful modification, eavesdropping, tracking, or privacy of individuals because RFID systems use the radio frequency and RFID tags. Therefore we create a key using hash chain between database and tag and this process can prevent above attacks. Also we support the efficiency of proposed protocol using hash function to abate computation.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.6
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• pp.201-208
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• 2010

The classical iterated hash function is vulnerable to a multi-collision attack. Gauravaram et al. proposed 3C and 3C+ hash functions, in which an accumulation chain is added to usual Merkle-Damgard changing. Their goal is to design composition schemes resistant to generic attacks of Joux's type, but Joscak and Tuma have shown that 3C and 3C+ schemes are not better than Merkle-Damgard scheme in term of security against multi-collision attacks under some mild assumptions. In this dissertation, in order to increase security of 3C hash function, we proposed secure double pipe hash function which was effectively using XOR and XNOR operations per blocks of message. We seek to improve on the work of Lucks in a way. Proposed secure double pipe hash function takes resistance to multi-block collision, fixed point and pre-image attacks.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.5
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• pp.1049-1056
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• 2010

Recently RFID system has been adopted in various fields rapidly. However, we should solve the problem of privacy invasion that can be occurred by obtaining information of RFID Tag without any permission for popularization of RFID system. To solve these problems, There is the Ohkubo et al.'s Hash-Chain Scheme which is the safest method. However, this method has a problem that requesting lots of computing process because of creasing numbers of Tag. Therefore We, suggest SP-Division algorithm satisfied with all necessary security of Privacy Protection Scheme and decreased in Tag Identification Time in this paper. And this paper implemented it in time standard finding the first key among the data devided into each nodes. The length of Hash-Chain holds 1000, and the total number of SPs increases 1000, 2000, 3000, and 4000. Comparing tag identification time by the total number of SPs and the number of Nodes with single node, extending the number of nodes to 1, 2, 3 and 4, when the number of nodes is 2, 40% of Performance, when the number of nodes is 3, 56%, and when the number of nodes is 4, 71% is improved.

• Journal of the Korea Society of Computer and Information
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• v.13 no.1
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• pp.161-167
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• 2008

As the authentication and the integrity methods based on the hash chain are popular, several certificate status validation methods based on the same function are proposd at the moment. In NOVOMODO, a CA generates and releases the hash value to each user. In Jianying Zhou's framework and Jong-Phil Yang's framework, a user generates and releases the hash value to verifier. Therefore, the CA loads are distributed to each user. However, these frameworks are based on the assumption that the CA's secret key is not lost or compromised and the certificates issued by the CA are error-free. Therefore, these frameworks are not suitable in real PKI environments. In this paper, as one hash value generated by CA is included in the user's certificate in addition, the certificate revocation published by CA using that value can be managed. The hash value included in user's certificate is the same for all users. The computation costs, the storage amounts and the release costs are small in the CA. And we modify the procedure for the signature and its validation in Jong-Phil Yang's framework. Our solution is more suitable than those frameworks in real PKI environments.

• Journal of the Korea Society for Simulation
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• v.25 no.3
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• pp.77-83
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• 2016

A new key generation scheme is proposed to support partial encryption and partial decryption of data in cloud computing environment with a minimal key-related traffic overhead. Our proposed scheme employs a concept of hash tree chain to reduce the number of keys that need to be delivered to the decryption node. The performance of the proposed scheme is evaluated through simulation.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.04a
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• pp.710-713
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• 2012

최근 스마트 기기는 결제, 할인쿠폰 등 각종 기능을 제공하는 수단으로 진화되면서 통신과 금융이 융합된 모바일 NFC 서비스의 시장이 급성장할 것으로 전망되고 있다. 특히 모바일 NFC 결제 서비스 시장의 활성화가 예상됨에 따라 모바일 NFC 결제 서비스는 국내 외적으로 널리 주목받고 있다. 하지만 이를 주도할 수 있는 보안 관련 기술력이 부족한 상태이며 NFC 모바일 결제 환경에서 적용이 가능한 NFC 결제 관련 기술 연구도 미흡한 실정이다. 이에 따라 기존 방식과는 전혀 다른 결제 환경과 결제 방식에 의해 도출될 수 있는 다양한 응용서비스에 대한 새로운 법 제도의 정비와 새로운 결제환경에 맞는 보안기술이 필요할 것으로 예상된다. 본 논문에서는 기존의 물리적인 플라스틱 신용카드의 권한 위임 문제와 NFC 모바일 신용카드를 비교하여 NFC 모바일 기반 결제 서비스 상에서의 위협을 분석하고 NFC 결제환경에서 안전한 결제 권한 위임이 가능한 Hash Chain기반의 Time-Stamping Proxy 서명 기술을 제안하였다.

• IEMEK Journal of Embedded Systems and Applications
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• v.5 no.3
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• pp.118-127
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• 2010

Inter-vehicle communication is one of the most important parts in Intelligent Vehicle System. Through this communication, drivers can recognize what is happening out of their sights, such as the freezing condition of the street, traffic accidents, and so on. Each car in IVS gives various services to the drivers after analyzing those received information from cars or a base station. If the message is, however, exchanged from car to car directly, the computation cost which is needed for all the car to authenticate the transmitted message between nearby cars is tremendously high. Therefore, one can naturally think that the message communication between cars is performed with the help of the base station to reduce the computation cost. In this case where the base station collects all the information transmitted from cars and broadcasts them nearby, there should be an efficient way both for the base station to authenticate the car message within its communication range and for the car to authenticate the information received from the base station. In this paper, we present a two-way authentication protocol using a hash chain to efficiently exchange GPS information between a car and a base station. This information can be used to provide a driver with the navigation which displays all the moving cars around him in real time. When a car goes into an area of a base station, the car authenticates itself to the base station using its private key of PKI, sends a commitment of a hash chain, then starts to send a message with the hash value for authentication. The message includes GPS information, driver's status and so on. The base station also authenticates itself to the nearby cars using its private key, transmits the commitment of the hash chain, and sends all the messages gathered from cars with authentication information.