• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.313-316
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• 2002

This paper presents the design and implementation of a crypto processor, a special-purpose microprocessor optimized for the execution of cryptography algorithms. This crypto processor can be used fur various security applications such as storage devices, embedded systems, network routers, etc. The crypto processor consists of a 32-bit RISC processor block and a coprocessor block dedicated to the SEED and triple-DES (data encryption standard) symmetric key crypto (cryptography) algorithms. The crypto processor has been designed and fabricated as a single VLSI chip using 0.5 $\mu\textrm{m}$ CMOS technology. To test and demonstrate the capabilities of this chip, a custom board providing real-time data security for a data storage device has been developed. Testing results show that the crypto processor operates correctly at a working frequency of 30MHz and a bandwidth o1240Mbps.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.18 no.1
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• pp.170-191
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• 2024

The transmission of confidential data using cover media is called steganography. The three requirements of any effective steganography system are high embedding capacity, security, and imperceptibility. The text file's structure, which makes syntax and grammar more visually obvious than in other media, contributes to its poor imperceptibility. Text steganography is regarded as the most challenging carrier to hide secret data because of its insufficient redundant data compared to other digital objects. Unicode characters, especially non-printing or invisible, are employed for hiding data by mapping a specific amount of secret data bits in each character and inserting the character into cover text spaces. These characters are known with limited spaces to embed secret data. Current studies that used Unicode characters in text steganography focused on increasing the data hiding capacity with insufficient redundant data in a text file. A sequential embedding pattern is often selected and included in all available positions in the cover text. This embedding pattern negatively affects the text steganography system's imperceptibility and security. Thus, this study attempts to solve these limitations using the Part-of-speech (POS) tagging technique combined with the randomization concept in data hiding. Combining these two techniques allows inserting the Unicode characters in randomized patterns with specific positions in the cover text to increase data hiding capacity with minimum effects on imperceptibility and security. Format-preserving encryption (FPE) is also used to encrypt a secret message without changing its size before the embedding processes. By comparing the proposed technique to already existing ones, the results demonstrate that it fulfils the cover file's capacity, imperceptibility, and security requirements.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.1
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• pp.83-94
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• 2015

Deduplication, which is a technique of eliminating redundant data by storing only a single copy of each data, provides clients and a cloud server with efficiency for managing stored data. Since the data is saved in untrusted public cloud server, however, both invasion of data privacy and data loss can be occurred. Over recent years, although many studies have been proposed secure deduplication schemes, there still remains both the security problems causing serious damages and inefficiency. In this paper, we propose secure and efficient client-side deduplication with Key-server based on Bellare et. al's scheme and challenge-response method. Furthermore, we point out potential risks of client-side deduplication and show that our scheme is secure against various attacks and provides high efficiency for uploading big size of data.

• Journal of Information Technology Applications and Management
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• v.27 no.4
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• pp.1-19
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• 2020

Infringement of information security has caused the corporate image to be damaged and share price to fall, and it is emerging as an organizational risk. The value of information assets in enterprises has led to a higher level of security than in the past. As a result, companies are aware of the need for officers to protect information and to oversee a security management system. However, despite the growing importance of information security officers, there is a lack of research on their roles and characteristics. This study validates the relationship between determinants that affect the performance of information security. And a structural equation model was presented and empirically analyzed to see the impact of the internal and external characteristics of the staff in charge of information security on the organization's information security performance.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.24 no.5
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• pp.961-968
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• 2014

In order to prevent leakage of personal information by insiders a large number of companies install pc security solutions like DRM(Digital Right Management), DLP(Data Loss Prevention), Personal information filtering software steadily. However, despite these investments anomalies personal information occurred. To establish proper security policy before implementing pc security solutions, companies can prevent personal information leakage. Furthermore by analyzing the log from the solutions, companies verify the policies implemented effectively and modify security policies. In this paper, we define the required security solutions installed on PC to prevent disclosure of personal information in a variety of PC security solution, plan to integrate operations of the solutions in the blocking personal information leakage point of view and propose security policies through PC security solution log analysis.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.04a
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• pp.844-847
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• 2011

Wireless mesh network (WMN) is a type of mobile ad-hoc network consists of wireless router, mobile clients and gateway which connects the network with the Internet. To provide security in the network it is required to encrypt the message sent among the communicating nodes in such way so that only legitimate user can retrieve the original data. Several security mechanisms have been proposed so far to enhance the security of WMN. However, there still exists a need for a comprehensive mechanism to prevent attacks in data communication. Considering the characteristic of mesh network, in this paper we proposed a public key cryptography based security architecture to establish a secure key agreement among communicating nodes in mesh network. The proposed security architecture consists of two major sections: client data protection and network data protection. Client data protection deals with the mutual authentication between the client and the access router and provide client to access router encryption for data confidentiality using standard IEEE 802.11i protocol. On the other hand, network data protection ensures encrypted routing and data transfer in the multi hop backbone network. For the network data protection, we used the pre-distributed public key to form a secure backbone infrastructure.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.4
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• pp.2219-2236
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• 2017

With cloud storage services, users can handle an enormous amount of data in an efficient manner. However, due to the widespread popularization of cloud storage, users have raised concerns about the integrity of outsourced data, since they no longer possess the data locally. To address these concerns, many auditing schemes have been proposed that allow users to check the integrity of their outsourced data without retrieving it in full. Yuan and Yu proposed a public auditing scheme with a deduplication property where the cloud server does not store the duplicated data between users. In this paper, we analyze the weakness of the Yuan and Yu's scheme as well as present modifications which could improve the security of the scheme. We also define two types of adversaries and prove that our proposed scheme is secure against these adversaries under formal security models.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.12
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• pp.5058-5072
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• 2015

Quaternions have been commonly employed in color image processing, but when the existing pure quaternion representation for color images is used in perceptual hashing, it would degrade the robustness performance since it is sensitive to image manipulations. To improve the robustness in color image perceptual hashing, in this paper a full quaternion representation for color images is proposed by introducing the local image luminance variances. Based on this new representation, a novel Full Quaternion Discrete Cosine Transform (FQDCT)-based hashing is proposed, in which the Quaternion Discrete Cosine Transform (QDCT) is applied to the pseudo-randomly selected regions of the novel full quaternion image to construct two feature matrices. A new hash value in binary is generated from these two matrices. Our experimental results have validated the robustness improvement brought by the proposed full quaternion representation and demonstrated that better performance can be achieved in the proposed FQDCT-based hashing than that in other notable quaternion-based hashing schemes in terms of robustness and discriminability.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.2
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• pp.587-608
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• 2022

The European Union recently established the General Data Protection Regulation (GDPR) for secure data use and personal information protection. Inspired by this, South Korea revised their Personal Information Protection Act, the Act on Promotion of Information and Communications Network Utilization and Information Protection, and the Credit Information Use and Protection Act, collectively known as the "Three Data Bills," which prescribe safe personal information use based on pseudonymous data processing. Based on these bills, the personal data store (PDS) has received attention because it utilizes the MyData service, which actively manages and controls personal information based on the approval of individuals, and it practically ensures their rights to informational self-determination. Various types of PDS models have been developed by several countries (e.g., the US, Europe, and Japan) and global platform firms. The South Korean government has now initiated MyData service projects for personal information use in the financial field, focusing on personal credit information management. There is also a need to verify the efficacy of this service in diverse fields (e.g., medical). However, despite the increased attention, existing MyData models and frameworks do not satisfy security requirements of ensured traceability, transparency, and distributed authentication for personal information use. This study analyzes primary PDS models and compares them to an internationally standardized framework for personal information security with guidelines on MyData so that a proper PDS model can be proposed for South Korea.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.5
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• pp.2414-2428
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• 2018

In order to solve the problem that the current network security situation assessment methods just focus on the attack behaviors, this paper proposes a kind of network security situation assessment method based on Markov Decision Process and Game theory. The method takes the Markov Game model as the core, and uses the 4 levels data fusion to realize the evaluation of the network security situation. In this process, the Nash equilibrium point of the game is used to determine the impact on the network security. Experiments show that the results of this method are basically consistent with the expert evaluation data. As the method takes full account of the interaction between the attackers and defenders, it is closer to reality, and can accurately assess network security situation.