• Archives of Plastic Surgery
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• v.40 no.6
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• pp.779-782
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• 2013

Chondroblastomas are rare entities accounting for approximately 1% of all primary bone tumors. We describe a case of a 7-year-old girl with a giant chondroblastoma of the maxilla, treated with bilateral class III maxillectomy and reconstruction with a double-barreled and double skin paddle fibular free flap. We show evidence of an excellent aesthetic outcome at 6 months' follow up with no evidence of tumor recurrence.

• International Journal of Computer Science & Network Security
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• v.21 no.6
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• pp.119-126
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• 2021

The Internet of Things (IoT) applications are quickly spread in many fields. Blockchain methods (BC), defined as a distributed sharing mechanism, offer excellent support for IoT evolution. The BC provides a secure way for communication between IoT devices. However, the IoT environments are threatened by hacker attacks and malicious intrusions. The IoT applications security are faced with three challenges: intrusions and attacks detection, secure communication, and compressed storage information. This paper proposed a system based on double-blockchain to improve the communication transactions' safety and enhance the information compression method for the stored data. Information security is enhanced by using an Ellipse Curve Cryptography (ECC) considered in a double-blockchain case. The data compression is ensured by the Compressed Sensing (CS) method. The conducted experimentation reveals that the proposed method is more accurate in security and storage performance than previous related works.

• International Journal of Internet, Broadcasting and Communication
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• v.13 no.4
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• pp.1-10
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• 2021

The purpose of the study is to contribute to the positive development of blockchain technology by providing data to examine security vulnerabilities and threats to blockchain-based services and review countermeasures. The findings of this study are as follows. Threats to the security of blockchain-based services can be classified into application security threats, smart contract security threats, and network (P2P) security threats. First, application security threats include wallet theft (e-wallet stealing), double spending (double payment attack), and cryptojacking (mining malware infection). Second, smart contract security threats are divided into reentrancy attacks, replay attacks, and balance increasing attacks. Third, network (P2P) security threats are divided into the 51% control attack, Sybil attack, balance attack, eclipse attack (spread false information attack), selfish mining (selfish mining monopoly), block withholding attack, DDoS attack (distributed service denial attack) and DNS/BGP hijacks. Through this study, it is possible to discuss the future plans of the blockchain technology-based ecosystem through understanding the functional characteristics of transparency or some privacy that can be obtained within the blockchain. It also supports effective coping with various security threats.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.26 no.6
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• pp.1353-1360
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• 2016

We analyze the efficiency of the double-block-length hash functions, Abreast-DM, HIROSE, MDC-2, MJH, MJH-Double based on AES or LEA. We use optimized open-source code for AES, and our implemented source code for LEA. As a result, the hash functions based on LEA are generally more efficient than those, based on AES. In terms of speed, the hash function with LEA are 6%~19% faster than those with AES except for Abreast-DM. In terms of memory, the hash functions with LEA has 20~30 times more efficient than those with AES.

• The KIPS Transactions:PartC
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• v.14C no.3 s.113
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• pp.239-254
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• 2007

Ubiquitous computing supports environment to freely connect to network without restrictions of place and time. This environment enables easy access and sharing of information, but because of easy unauthorized accesses, specified security policy is needed. Especially, ubiquitous sensor network devices use limited power and are small in size, so, many restrictions on policies are bound to happen. This paper proposes double-key based light weight security protocol, independent to specific sensor OS, platform and routing protocol in ubiquitous sensor network. The proposed protocol supports safe symmetric key distribution, and allows security manager to change and manage security levels and keys. This had a strong merit by which small process can make large security measures. In the performance evaluation, the proposed light weight security protocol using double-key in ubiquitous sensor network allows relatively efficient low power security policy. It will be efficient to ubiquitous sensor network, such as smart of ace and smart home.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.28 no.2
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• pp.449-456
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• 2018

Many organizations divide the network to manage the network in order to prevent the leakage of internal data between separate organizations / departments by sending and receiving unnecessary traffic. The most fundamental network separation method is based on physically separate equipment. However, there is a case where a network is divided and operated logically by utilizing a virtual LAN (VLAN) network access control function that can be constructed at a lower cost. In this study, we first examined the possibility of bypassing the logical network separation through VLAN ID scanning and double encapsulation VLAN hopping attack. Then, we showed and implemented a data leak scenario by utilizing the acquired VLAN ID. Furthermore, we proposed a simple and effective technique to detect and prevent the double encapsulation VLAN hopping attack, which is also implemented for validation. We hope that this study improves security of organizations that use the VLAN-based logical network separation by preventing internal data leakage or external cyber attack exploiting double encapsulation VLAN vulnerability.

• Journal of information and communication convergence engineering
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• v.13 no.4
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• pp.280-285
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• 2015

Double random phase encryption (DRPE) is one of the well-known optical encryption techniques, and many techniques with DRPE have been developed for information security. However, most of these techniques may not solve the fundamental security problem caused by using fixed phase masks for DRPE. Therefore, in this paper, we propose a key phase mask updating scheme for DRPE to improve its security, where a spatial light modulator (SLM) is used to implement key phase mask updating. In the proposed scheme, updated key data are obtained by using previous image data and the first phase mask used in encryption. The SLM with the updated key is used as the second phase mask for encryption. We provide a detailed description of the method of encryption and decryption for a DRPE system using the proposed key updating scheme, and simulation results are also shown to verify that the proposed key updating scheme can enhance the security of the original DRPE.

• Journal of Korea Society of Digital Industry and Information Management
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• v.17 no.4
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• pp.43-52
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• 2021

IoT applications are quickly spread in many fields. Blockchain methods(BC), defined as a distributed sharing mechanism, offer excellent support for IoT evolution. The BC provides a secure way for communication between IoT devices. However, the IoT environments are threatened by hacker attacks and malicious intrusions. The IoT applications security are faced with three challenges: intrusions and attacks detection, secure communication, and compressed storage information. This paper proposed a system based on double-blockchain to improve the communication transactions' safety and enhance the information compression method for the stored data. Information security is enhanced by using an Ellipse Curve Cryptography(ECC) considered in a double-blockchain case. The data compression is ensured by the Compressed Sensing(CS) method. The conducted experimentation reveals that the proposed method is more accurate in security and storage performance than previous related works.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.20 no.2
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• pp.33-41
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• 2010

Many experimental results shows that RSA-CRT algorithm can be broken by fault analysis attacks. We analyzed the previous fault attacks and their countermeasures on RSA-CRT algorithm and found an weakness of the countermeasure proposed by Abid and Wang. Based on these analyses, we propose a new countermeasure which uses both double exponentiation and fault infective computation method. The proposed method efficiently computes a fault verification information using double exponentiation. And, it is designed to resist simple power analysis attack and (N-1) attack.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.15 no.6
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• pp.81-92
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• 2005

A novel public key cryptosystem that provides a double decryption mechanism is proposed at Asiacrypt '03 by Bresson, Catalano and Pointcheval based on the scheme proposed by Clamor and Shoup at Eurocrypt '02. Previous double decryrtion scheme is designed based on $Z_n^2$ where n=pq for two primes p,q. In this paper, we propose an efficient public key scheme with double decryption mechanism based on $Z_p^2_q$ for two primes p,q. Our scheme is more efficient an the previous schemes. Moreover, we review the previous schemes in a privacy point of view and propose a privacy enhanced double decryption scheme.