• Parasites, Hosts and Diseases
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• v.51 no.2
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• pp.197-201
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• 2013

A total of 16 Taenia multiceps isolates collected from naturally infected sheep or goats in Gansu Province, China were characterized by sequences of mitochondrial cytochrome c oxidase subunit 1 (cox1) gene. The complete cox1 gene was amplified for individual T. multiceps isolates by PCR, ligated to pMD18T vector, and sequenced. Sequence analysis indicated that out of 16 T. multiceps isolates 10 unique cox1 gene sequences of 1,623 bp were obtained with sequence variation of 0.12-0.68%. The results showed that the cox1 gene sequences were highly conserved among the examined T. multiceps isolates. However, they were quite different from those of the other Taenia species. Phylogenetic analysis based on complete cox1 gene sequences revealed that T. multiceps isolates were composed of 3 genotypes and distinguished from the other Taenia species.

• Journal of KIISE:Software and Applications
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• v.31 no.9
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• pp.1218-1225
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• 2004

S/KEY system was proposed to guard against intruder's password replay attack. But S/KEY system has vulnerability that if an attacker derive passphrase from his dictionary file, he can acquire one-time password required for user authentication. In this paper, we propose a correct S/KEY system mixed with EKE to solve the problem. Also, we specify a new S/KEY system with Casper and CSP, verify its secrecy and authentication requirements using FDR model checking tool.

• Journal of Microbiology and Biotechnology
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• v.16 no.12
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• pp.1882-1889
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• 2006

A 16S rDNA clone library was generated to investigate the bacterial diversity in intertidal sediment from the coast of the Yellow Sea, P. R. China. A total of 102 clones were sequenced and grouped into 73 OTUs using a phylogenetic approach. The sequenced clones fell into 11 bacterial lineages: Proteobacteria, Bacteroidetes, Planctomycetes, Chloroflexi, Acidobacteria, Actinobacteria, Firmicutes, Spirochaetes, and candidate divisions of BRCl, OP3, and OP1l. Based on a phylogenetic analysis of these bacteria, together with the ten most closely related sequences deposited in the GenBank, it was concluded that intertidal bacteria are most likely derived from marine bacteria with a remarkable diversity, and some are particularly abundant in intertidal sediment.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.6
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• pp.1109-1122
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• 2016

Certificateless public key cryptography is a technique that can solve the certificate management problem of a public key cryptosystem and clear the key escrow issue of ID-based cryptography using the public key in user ID. Although the studies were actively in progress, many existing schemes have been designed without taking into account the safety of the secret value with the decryption key exposure attacks. If previous secret values and decryption keys are exposed after replacing public key, a valid private key can be calculated by obtaining the partial private key corresponding to user's ID. In this paper, we propose a new security model which ensures the security against the key exposure attacks and show that several certificateless public key encryption schemes are insecure in the proposed security model. In addition, we design a certificateless public key encryption scheme to be secure in the proposed security model and prove it based on the DBDH(Decisional Bilinear Diffie-Hellman) assumption.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.4
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• pp.479-488
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• 2016

For a secure communication system, it is necessary to use secure cryptographic algorithms and keys. Modern cryptographic system generates high entropy encryption key through standard key derivation functions. Using recent progress in quantum key distribution(QKD) based on quantum physics, it is expected that we can enhance the security of modern cryptosystem. In this respect, the study on the dual key agreement is required, which combines quantum and modern cryptography. In this paper, we propose two key derivation functions using dual key agreement based on QKD and RSA cryptographic system. Furthermore, we demonstrate several simulations that estimate entropy of derived key so as to support the design rationale of our key derivation functions.

• Journal of the Korea Society of Computer and Information
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• v.11 no.6 s.44
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• pp.35-47
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• 2006

In an Ubiquitous Environment, the growth of various services and equipment is forecasted to increase both the multicast users and diverse hacking attacks of the multicast key. Rapid increasing of multicast users and application security protocols reduce the performance of the Central key management system. Accordingly. We propose to elevate the functionality of the key management mechanism for greater efficiency and stability of the multicast services. in this paper The existing key management mechanism comparison and simulation will analyze these problems. We propose the advanced SMKD (Secure Multicast Key Distribution) mechanism application of the small group and key length control new security protocol by methods to solve these problems. The SMKD Model in this paper will help reduce loading the key distribution and encryption execution of a central key management system, and this model can also ensure stability to a central key management system by efficient key management.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.5
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• pp.1082-1088
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• 2005

Generating fast round key in AES Rijndael algorithm using three key sizes, such as 128, 192, and 256-bit keys is a critical factor to develop high throughput AES processors. In this paper, we propose on-the-fly round key generator which is applicable to the pipelined and non-pipelined AES processor in which cipher and decipher nodes must be implemented on a chip. The proposed round key generator has modular and area-and-time efficient structure implemented with simple connection of two key expander modules, such as key_exp_m and key_exp_s module. The round key generator for non-pipelined AES processor with support of three key lengths and cipher/decipher modes has about 7.8-ns delay time under 0.25um 2.5V CMOS standard cell library and consists of about 17,700 gates.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.2
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• pp.353-360
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• 2017

The Internet of Things(IoT) security has more need than a technical problem as it needs series of regulations and faultless security system for common purposes. So, this study proposes an efficient key management in order that can be trusted IoT data in cloud computing. In contrast with a key distribution center of existing sensor networks, the proposed a federation key management of cloud proxy key server is not central point of administration and enables an active key recovery and update. The proposed key management is not a method of predetermined secret keys but sharing key information of a cloud proxy key server in autonomous cloud, which can reduce key generation and space complexity. In addition, In contrast with previous IoT key researches, a federation key of cloud proxy key server provides an extraction ability from meaningful information while moving data.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.680.1-680.1
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• 2006

• Proceedings of the Korean Magnestics Society Conference
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• 2008.12a
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• pp.10.1-10.1
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• 2008