• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.1
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• pp.245-251
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• 2014

Mix network plays a key role in electronic voting to preserve anonymity and lots of mixnet schemes have been proposed so far. However, they requires complex and costly zero-knowledge proofs to provide their correct mixing operations. In 2010, Seb$\acute{e}$ et al. proposed an efficient and lightweight mixnet scheme based on a cryptographic secure hash function instead of zero-knowledge proofs. In this paper, we present a more efficient and faster mixnet scheme than Seb$\acute{e}$ et al.'s scheme under the same assumption. Also, our scheme is secure.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.22 no.3
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• pp.417-425
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• 2012

In 2010, Sebe et al. proposed an efficient and lightweight mixnet scheme for remote voting systems. The scheme based on a cryptographic secure hash function, does not require complex and costly zero-knowledge proofs of their correct mixing operations, thus they claimed that their scheme is simple and efficient. In this paper, we propose more efficient and fast mixnet scheme than Sebe et al.'s scheme under the same assumption.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.246-248
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• 2021

Recently data has been transformed into a data economy and society that acts as a catalyst for the development of all industries and the creation of new value, and COVID-19 is accelerating digital transformation. In the upcoming intelligent Internet of Things era, the availability of decentralized systems such as blockchain and mixnet is emerging to solve the security problems of centralized systems that makes it difficult to utilize data safely and efficiently. Blockchain manages data in a transparent and decentralized manner and guarantees the reliability and integrity of the data through agreements between participants, but the transparency of the data threatens the privacy of users. On the other hand, mixed net technology for protecting privacy protects privacy in distributed networks, but due to inefficient power consumption efficiency and processing speed issues, low cost, light weight, low power consumption Internet Hard to use. In this paper, we analyze the limitations of conventional mixed-net technology and propose a mixed-net technology method for low power consumption, high speed, and the Internet of things.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2005.11a
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• pp.247-250
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• 2005

Recently, a concept of bid-rigging is issued in electronic auction. To prevent this attack, Abe-Suzuki proposed firstly receipt-free scheme based on bidding-booth. Chen-Lee-Kim pointed out that Abe-Suzuki's scheme only provides receipt-freeness for losing bidders. Also, they introduced a new receipt-free sealed bid auction scheme using the homomorphic encryption technique. The main participants of their scheme are Auctioneer, Auction Issuer, Bidder and Seller. Bid-rigging can happen by a seller in their scheme. We propose receipt-free sealed-bid auction scheme using a universal re-encryption mixnet. For our receipt-free sealed-bid auction, we use Pseudo ID of a bidder and universal re-encryption technique of Golle et al. Also, our scheme satisfies privacy, correctness, public verifiability, non-reputation, and receipt-freeness.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.22 no.1
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• pp.117-130
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• 2012

Recently, smartphone has being most popular mobile device in mobile market, not around the world, but in domestic. In Korea, there are about 710 million people are using smartphone in 2010, and it is expected that about 1 billion people will use smartphone in next year. However, with exponential growth of smartphone, several security issues come to the fore. Because, the smartphone store various private information to provide user customized services, smartphone security can be regarded most critical issues than security of other devices. However, leak of awareness for security may cause many security accidents in present. Therefore, in this paper, we analyze security features of smartphone and propose a protection profile based on Common Criteria v3.1. Our work can be distributed for developer and user of smartphone to estimate security of smartphone.

• Information Systems Review
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• v.25 no.4
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• pp.47-65
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• 2023

In this paper, we investigate how the online voting system can be a trust-based system from a technical perspective. Under four principles of voting, we finely evaluate the existing belief that offline voting is safer and more reliable than online voting based on procedural processes, technical principles. Many studies have suggested the ideas for implementing online voting system, but they have not attempted to strictly examine the technologies of online voting system from the perspective of voting requirements, and usually verification has been insufficient in terms of practical acceptance. Therefore, this study aims to analyze how the technologies are utilized to meet the demanding requirements of voting based on the technologies proven in the field. In addition to general data encryption, online voting requires more technologies for preventing data manipulation and verifying voting results. Moreover, high degree of confidentiality is required because voting data should not be exposed not only to outsiders but also to managers or the system itself. To this end, the security techniques such as Blind Signature, Bit Delegation and Key Division are used. In the case of blockchain-based voting, Mixnet and Zero-Knowledge Proof are required to ensure anonymity. In this study, the current status of the online voting system is analyzed based on the field system that actually serves. This study will enhance our understanding on online voting security technologies and contribute to build a more trust-based voting mechanism.