• 정보보호학회논문지
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• 제10권3호
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• pp.37-48
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• 2000

서울Visual cryptography scheme is a simple method in which can be directly decoded the secret information in human visual system without performing any cryptographic computations. This scheme is a kind of secret sharing scheme in which if a secret of image type is scattered to n random images(slides) and any threshold (or more) of them are stacked together the original image will become visible. In this paper we consider (2, n) visual cryptography scheme and propose a new construction method in which the number of expanded pixels can be reduced by using the sample matrix. The proposed scheme can futhermore distribute the multiple secret image to each group according to the difference of relative contrast.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권10호
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• pp.5144-5160
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• 2019

Secret sharing is an effective way of protecting secret messages. However, the traditional secret sharing schemes are considered meaningless due to malicious people attention which might raise risks. To overcome the weakness, this paper presents an effective secret sharing scheme with the functionality of cheater identification, based on meaningful QR code. The secret message will be split and concealed in the padding region of cover QR codes with the assistance of Latin square and it can be completely restored when all the involved participants cooperate. The concealing strategy exploits the characteristic of Reed-Solomon (RS) code to ensure the strong robustness of generated QR code pseudo-shares. The meaningful QR code pseudo-shares help to reduce the curious of unrelated persons. Some experiments were done to evaluate the performance of proposed scheme. The results showed that the proposed scheme is feasible, efficient and secure compared to the other existing schemes. It also achieves a higher secret payload and maintains stronger robustness.

• 한국정보과학회논문지:시스템및이론
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• 제30권5_6호
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• pp.239-249
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• 2003

비밀 분산(Secret Sharing)은 임계 암호시스템(Threshold Cryptosystem)의 기본 개념이며, 현대 암호학에서 중요한 한 축을 이루는 암호학의 한 분야이다. 1995년 Jarecki는 이동 공격자 모델에 대하여 비밀 분산 프로토콜의 안전성을 유지할 수 있는 능동적 비밀 분산(Proactive Secret Sharing) 개념을 제안하였고, 이와 함께 (k, n) threshold scheme에서 능동적 비밀 분산을 적용하기 위하여 공유 갱신 프로토콜을 제안하였다. Jarecki가 제안한 공유 갱신 프로토콜은 전체 참여자가 n명일 경우 각 참여자당 $O(n^2)$의 모듈라 멱승 연산을 수행하여야 한다. 이것은 매우 큰 연산량으로 참여자가 큰 대규모의 비밀 분산 수행시 계산 비용의 증가로 Jarecki의 프로토콜은 사용하기 어렵게 된다. 본 논문에서는 (k, n) threshold scheme에서의 능동적 비밀 분산을 위한 효율적인 공유 갱신 방법을 제안한다. 제안 방법은 이전 방법과는 달리 각 참여자당 O(n)의 모듈라 멱승 연산만으로 공유 갱신이 가능하다. 이와 함께 본 논문에서는 k(클n-1 인 경우에 대하여 제안 방법의 안전함을 증명한다.

• 정보처리학회논문지C
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• 제11C권5호
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• pp.563-568
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• 2004

비밀분산방식에서, 재구성된 비밀은 참가자에게 노출된다. 동일한 비밀분산 방식을 유지하기 위해서, 새로운 비밀을 생성하고 참가자에게 재분배하여야 한다. 그러한 재생성과정은 비효율적이다. 본 논문은 참가자에게 노출되지 않고 고유치에 의해 효율적인 비밀 재생성과 재분배할 수 있는 방식을 제안한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권12호
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• pp.4552-4567
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• 2014

A (n,t,n) secret sharing scheme is to share a secret among n group members, where each member also plays a role of a dealer,and any t shares can be used to recover the secret. In this paper, we propose a strong (k,t,n) verifiable multi-secret sharing scheme, where any k out of n participants operate as dealers. The scheme realizes both threshold structure and adversary structure simultaneously, and removes a trusted third party. The secret reconstruction phase is performed using an additive homomorphism for decreasing the storage cost. Meanwhile, the scheme achieves the pre-verification property in the sense that any participant doesn't need to reveal any information about real master shares in the verification phase. We compare our proposal with the previous (n,t,n) secret sharing schemes from the perspectives of what kinds of access structures they achieve, what kinds of functionalities they support and whether heavy storage cost for secret share is required. Then it shows that our scheme takes the following advantages: (a) realizing the adversary structure, (b) allowing any k out of n participants to operate as dealers, (c) small sized secret share. Moreover, our proposed scheme is a favorable candidate to be used in many applications, such as secure multi-party computation and privacy preserving data mining, etc.

• 한국정보처리학회논문지
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• 제7권10호
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• pp.3128-3137
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• 2000

비밀분산이란 비밀정보에 대한 부분 정보를 여러 참가자들에게 분배하였다가 필요한 경우에 허가된 참가자들의 협조에 의해서만 복원이 가능하도록 하는 암호학적 기술을 말한다. 이러한 비밀분산은 비밀정보의 관리뿐만 아니라 다자간 프로토콜, 그룹 암호 방식 등의 분야에서 매우 중요한 부분이다. 본 논문에서는 일방향 해쉬함수에 기반한 효율적인 온라인 비밀분산 방식을 제안하고자 한다. 제안하는 방식은 하나의 부분 정보만으로 여러 개의 비밀을 분산할 수 있고, 액세스 구조가 변하는 경우에는 게시판에 공개된 값들만 변경하면 각 참가자들은 기존의 부분 정보를 그대로 사용할 수 있다. 또한 참가자들의 부정이 있는 경우 그 수에 관계없이 항상 부정한 참가자의 신분을 밝혀낼 수 있으며, 기존의 제안된 방식들보다 계산상 효율적이라는 장점이 있다.

• 한국컴퓨터정보학회논문지
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• 제21권9호
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• pp.73-78
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• 2016

In 2014, Wuu et al. proposed a group key management scheme based on (2,2) secret sharing. They asserted that their scheme satisfies security requirements and mutual authentication. But this paper pointed out that their scheme does not satisfy mutual authentication and impersonating attack. In this paper, we describe the reasons and processes that a malicious group member can impersonate the Group Key Distributor. To fill the gaps, we discuss the problems, and propose an improved protocol.

• 한국멀티미디어학회논문지
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• 제17권7호
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• pp.849-857
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• 2014

In this paper, we propose a (2,2)-reversible secret image sharing scheme using histogram shifting and difference expansion. Two techniques are widely used in information hiding. Advantages of them are the low distortion between cover and stego images, and high embedding capacity. In secret image sharing procedure, unlike Shamir's secret sharing, a histogram generate that the difference value between the original image and copy image is computed by difference expansion. And then, the secret image is embedded into original and copy images by using histogram shifting. Lastly, two generated shadow images are distributed to each participant by the dealer. In the experimental results, we measure a capacity of a secret image and a distortion ratio between original image and shadow image. The results show that the embedding capacity and image distortion ratio of the proposed scheme are superior to the previous schemes.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권7호
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• pp.2862-2878
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• 2020

Data Security is the most challenging area in Internet communication, where most of the secret sharing schemes are proposed for binary images. But still it lacks in providing security for data communication, especially in image transmission. Traditional visual cryptography scheme generate meaningless diwies and the reconstruction phase leads to quality degradation over the secret image. In this work, an intelligent two dimensional secret share construction scheme is proposed. A secret image is expanded into n diwies with the choice of scheme selection. By Stacking all the qualified diwies to revert the secret image without content loss and less than s^* - 1 shares could not reveal any information about the secret image. The experimental results emphasize that the proposed secret share scheme is highly secured for image transmission.

• 한국멀티미디어학회논문지
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• 제20권2호
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• pp.261-270
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• 2017

Data hiding is a way to hide the information in multimedia media such as images or video. The scheme proposed by Nguyen and Chang, was able to embed, extract, and restore the cover image and the secret data using Sudoku. But in the extracting phase, the occurrence of duplicate values in the reference matrix was found to decrease the embedding capacity of secret data. This paper has proposed a reversible data hiding scheme while maintaining the quality of the image to provide high embedding capacity using $7{\times}7$ Sudoku and Shamir's secret sharing scheme.