• Journal of the Korea Institute of Information Security & Cryptology
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• v.26 no.2
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• pp.345-358
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• 2016

In this paper, we present a security tool which called Digital Legal Seal. The Digital Legal Seal scans a barcode on a paper and print it with the tag generated by Hash-based Message Authentication Code(HMAC) in text format on a display device. The result of HMAC can be used for user authentication or secure message transmission on both online and offline. We examine not only how the Digital Legal Seal can make up the weak points of security card and OTP (One Time Password), but also the possibility of reducing the forgery of promissory note on offline.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.5
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• pp.999-1008
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• 2017

In this paper, we propose a pipeline network coding (PNC) scheme for efficient data transmission in wireless networks, a data authentication scheme for verifying the integrity of data, and a node authentication scheme for a virtual source. PNC is a technique that improves the overall network performance by relaying data such that the relay node performing network coding transmits to the sender instead. However, network coding is vulnerable to a pollution attack, which is an attack by a malicious attacker to inject modified data into the network. To prevent this, hash-based message authentication code (HMAC) is used. For this purpose, in order to generate a tag used for data authentication, a key must be distributed to the nodes performing authentication. We applied a hash chain to minimize the overhead of key distribution. A null vector is used as the authentication scheme for the virtual source. Finally, we analyze the safety and complexity of the proposed scheme and show he performance through simulation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.4
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• pp.747-754
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• 2016

DHCP(Dynamic Host Configuration Protocol) is a protocol for efficiency and convenience of the IP address management. DHCP automatically assigns an IP address and configuration information needed to run the TCP/IP communication to individual host in the network. However, existing DHCP is vulnerable for network attack such as DHCP spoofing, release attack because there is no mutual authentication systems between server and client. To solve this problem, we have designed a new DHCP protocol supporting the following features: First, ECDH(Elliptic Curve Diffie-Hellman) is used to create session key and ECDSA(Elliptic Curve Digital Signature Algorithm) is used for mutual authentication between server and client. Also this protocol ensures integrity of message by adding a HMAC(Hash-based Message Authentication Code) on the message. And replay attacks can be prevented by using a Nonce. As a result, The receiver can prevent the network attack by discarding the received message from unauthorized host.

• Proceedings of the IEEK Conference
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• 2002.07b
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• pp.948-950
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• 2002

IPSec authentication provides support for data integrity and authentication of IP packets. Authentication is based on the use of a message authentication code(MAC). Hash function algorithm is used to produce MAC , which is referred to HMAC. In this paper, we propose a cryptographic accelerator using FPGA implementations. The accelator consists of a hash function mechanism based on MD5 algorithm, and a public-key generator based on a Elliptiv Curve algorithm with small scale of circuits. The accelator provides a messsage authentification as well as a digital signature. Implementation results show the proposed cryptographic accelerator can be applied to IPSec authentications.

• Journal of Korea Multimedia Society
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• v.11 no.6
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• pp.845-851
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• 2008

The ID/password method is the most classical method among authentication techniques on the internet, and is performed more easily and successfully than other methods. However, it is a vulnerable method against attacks such as eavesdropping or replay attack. To overcome this problem, OTP technique is used. The most popular OTP is HOTP algorithm, which is based on one-way hash function SHA-1. As recent researches show the weakness of the hash function, we need a new algorithm to replace HOTP. In this paper we propose a new OTP algorithm using the MAC(Message Authentication Code) based on AES. We also show that the new OTP outperforms HOTP experimentally.

• Journal of the Korea Society of Computer and Information
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• v.14 no.6
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• pp.27-32
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• 2009

Recently, most of information services are provided by the computer network, since the technology of computer communication is developing rapidly, and the worth of information over the network is also increasing with expensive cost. But various attacks to quietly intercept the informations is invoked with the technology of communication developed, and then most of the financial agency currently have used OTP, which is generated by a token at a number whenever a user authenticates to a server, rather than general static password for some services. A 2-Factor OTP generating method using the OTP token is mostly used by the financial agency. However, the method is vulnerable to real attacks and therefore the OTP token could be robbed and disappeared. In this paper, we propose a 3-Factor OTP way using HMAC to conquer the problems and analyze the security of the proposed scheme.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.47 no.1
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• pp.65-72
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• 2010

Nowadays, most hospitals have been used to create MRI or CT and managed them. Doctors depend on fast access to images such as magnetic resonance imaging (MRIs), computerized tomography (CT) scans, and X-rays for accurate diagnoses. Those image data are related privacy of a patient. Therefore, it should be protected from hackers and managed perfectly. In this paper, we propose a data hiding method into MRI or CT related a condition and intervention of a patient, and it is suggested that how to authenticate patient information from an image. In this way, we create hash code using HMAC with patient information, and hash code and patient information is hided into an image. After then, doctor will check authentication using HMAC. In addition, we use a reversible data hiding DE(Difference Expansion) algorithm to hide patient information. This technique is possible to reconstruct the original image with stego image. Therefore, doctor can easily be possible to check condition of a patient. As a consequence of an experiment with MRI image, data hiding, extraction and reconstruct is shown compact performance.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.701-704
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• 2007

Recently, More and more consumer enjoy the finance service such as settling, account transferring, stocks investment, and so via mobile device. In the mobile environment, data transferring between the devices is formatted as XML. However, the common XML file is exposed to the attack such as hacking and malignity code, to satisfy security of mobile environment is very difficult. The problem is more seriously at the open platform such as WIPI that is developed by our country. So there is enough reason to propose one system to protect the import data. In this paper, we development the system to digital signature and signature the XML document in order to protect data, and the system is observing the recommendation of the XML Signature Syntax and Processing by W3C. When designing and composition the system, we use the digital signature algorithm RSA, DSA, KCDSA, and HMAC, etc. we test the system at the open WIPI platform.