• Journal of the Korea Institute of Information Security & Cryptology
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• v.13 no.4
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• pp.139-149
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• 2003

In this paper a hardware design of area-efficient hash processor which implements MD5 algorithm using hardware sharing and carry-save addition schemes is described. To reduce area, the processor adopts hardware sharing scheme in which 1 step operation is divided into 2 substeps and then each substep is executed using the same hardware. Also to increase clock frequency, three serial additions of substep operation are transformed into two carry-save additions and one carry propagation addition. The MD5 hash processor is designed using 0.25 $\mu\textrm{m}$CMOS technology and consists of about 13,000 gates. From timing simulation results, the designed MD5 hash processor has 465 Mbps hash rates for 512-bit input message data under 120 MHz operating frequency.

• The KIPS Transactions:PartC
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• v.16C no.6
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• pp.669-680
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• 2009

By identifying the unique information of the objects using the RF, the RFID technique which will be able to manage the object is spot-lighted as the main technology in Ubiquitous era. On RFID systems, since the information of RFID may easily be unveiled in air, the secure and privacy problems always exist. In this paper, we propose mutual authentication protocol based on symmetric key. Proposed protocol has been able to minimize the tag's H/W resource by using symmetric key. And we use tag ID which is encrypted with hash function and a shared symmetric key by Challenge-Response pair of PUF(Physically Unclonable Function), thus there is no key disclosure problem in our protocol.

• Journal of Korea Society of Industrial Information Systems
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• v.10 no.3
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• pp.30-37
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• 2005

Ad hoc network is a collection of mobile nodes without using any infrastructure, it , is using in the various fields. Because ad hoc network is vulnerable to attacks such as routing disruption and resource consumption, it is in need of routing protocol security. In this paper, we propose two secure route-discovery protocols. One is a protocol using hash function. This protocol is weak in active attack but has some merits such as small data of transmission packet and small computation at each hop. The other is a protocol using hash function and public key cryptography. This protocol is strong in active attack.

• Journal of Advanced Navigation Technology
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• v.11 no.1
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• pp.93-98
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• 2007

The importance of information security is increasing by the rapid development of the communication network. So, cryptosystems are used to solve these problems and securities of cryptosystems are dependent on keys. In this paper, we propose a key generation method which is based on cryptographically secure MD5 hash function. The basic structure of the MD5 hash function features is a repetitive structure which is processed in a block unit of 512 bits from inputs of limited length and generates a fixed output of 128 bits. The security of proposed method is based on the hash function and the proposed method can be also utilized for authentication algorithm or data encryption algorithm.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.11
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• pp.2459-2464
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• 2009

In sensor network there are no nodes or servers that are exclusively responsible for packet forwarding and routing. Instead, sensor nodes participating in network communications perform these activities. Thus, they are vulnerable to the alteration and forgery of message in the process of packet forwarding and routing. To solve this problem, a security to ensure authentication and integrity of routing and forwarding messages should be required. To do this, we propose the hash chain-based digital signature model where it takes less time to compute in generating and verifying the digital signature model, unlike he public key-based digital signature model, and verify if this model is proper by comparing computation times between tow models.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.9
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• pp.41-48
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• 2004

In this work, a domain-wise hash structure is developed for efficient data handling, and by using the developed domain-wise hash structure, an automatic triangular mesh generation algorithm is proposed. To generate the optimal nodal points and triangles efficiently, the advancing layer method and Delaunay triangulation method are utilized. To investigate the performance of the proposed algorithm, benchmarking tests are carried out for various models including convex, concave and complicated shapes through the developed object oriented C++ mesh generation code.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.6C
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• pp.497-501
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• 2012

While increasing online services with developing e-businesses, finance, game companies and others have employed OTP(One-Time Password) to overcome vulnerabilities of static passwords. Existing OTP technology has inconvenience that customers always possess reserved token since requiring the token to generate OTP. In order to supplement the issue we propose mobile OTP generated by mobile devices such as smart phones. Our mobile OTP scheme generates OTP by using a non-linear function based on pairing to eject the collision problem of S/Key scheme universally used to design OTP schemes. Our scheme based on a non-linear function over pairing can complements the collision problem and widely applied to finance and various services to increase security level of the services.

• Journal of the Korea Society of Computer and Information
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• v.18 no.10
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• pp.81-88
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• 2013

Since nowadays mobile phone messages are flourishing, the application of electronic coupon (e-coupon) will become a trend for mobile users. E-coupon for mobile commerce can provide mobility for users and distribution flexibility for issuers. In this paper, we propose a mobile e-coupon system that just applies some simple cryptographic techniques, such as one-way hash function and XOR operation. In our system, the customer can control the number of issued e-coupons and the issuer can prevent them from double-redeeming. The customer does not need to perform any exponential computation in redeeming and transferring the coupons. Our scheme uses one-way hash chains for preventing from double-spending.

• The KIPS Transactions:PartD
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• v.9D no.4
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• pp.579-586
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• 2002

This paper propose an efficient algorithm for mining association rules in the large main memory systems. To do this, the paper attempts firstly to extend the conventional algorithms such as DHP and Partition in order to be compatible to the large main memory systems and proposes secondly an algorithm to improve Partition algorithm by applying the techniques of the hash table and the bit map. The proposed algorithm is compared to the extended DHP within the experimental environments and the results show up to 65% performance improvement in comparison to the expanded DHP.

• Journal of KIISE:Software and Applications
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• v.27 no.1
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• pp.41-49
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• 2000

This paper describes a method of generating MPHFs(Minimal Perfect Hash Functions) for large static search key sets. The MOS(Mapping-Ordering-Searching) approach is widely used presently in MPHF generation. In this research, the MOS approach is improved and a SOMS(Selecting-Ordering-Mapping-Searching) approach is proposed, where the Selecting step is newly introduced and the Orderng step is performed before the Mapping step to generate MPHFs more effectively. The MPHF generation algorithm proposed in this research is probabilistic and the expected processing time is linear to the number of keys. Experimental results show that MPHFs are generated fast and the space needed to represent the hash functions is small.