• Convergence Security Journal
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• v.21 no.1
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• pp.33-44
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• 2021

Data outsourcing utilizing the Cloud faces a problem of the third-party exposure, modulation, and reliability for the provided computational delegation results. In order to solve those problematic security issues, homomorphic encryption(HE) which executes calculation and analysis on encrypted data becomes popular. By extension, a new type of HE with a authentication functionality, homomorphic authenticated encryption(HAE) is suggested. However, a research on the HAE is on the initial stage. Furthermore, based on a message authenticated scheme with HE, the method and analysis to design is still absent. This paper aims to analyze an HAE, with a generic combination of a message authenticated scheme and a HE, known as "Encrypt with Authentication". Following a series of analysis, we show that by adopting a unforgeable message authenticated scheme, the generically constructed HAE demonstrated an unforgeability as well. Though, a strong unforgeability is not the case. This paper concludes that although indistinguishable HE can be applied to design the HAE, a security issue on the possibility of indistinguishability is still not satisfied.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.24 no.3
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• pp.461-475
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• 2014

Homomorphic MAC is a cryptographic primitive which protects authenticity of data, while allowing homomorphic evaluation of such protected data. In this paper, we present a new homomorphic MAC, which is based on integers, relying only on the existence of secure PRFs, and having efficiency comparable to the practical Catalano-Fiore homomorphic MAC. Our scheme is unforgeable even when MAC verification queries are allowed to the adversary, and we achieve this by showing strong unforgeability of our scheme.

• Journal of KIISE:Databases
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• v.32 no.3
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• pp.326-333
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• 2005

Many XML applications use XPath Patterns as a query language for XML documents. Two XPath patterns may have containment relationship, and the containment problem between two XPath patterns is a problem that determines whether one XPath pattern contains another XPath Pattern. Although the containment problem occurs in many applications, it is known as a co-NP complete. A homomorphism problem, which is a sufficient condition for the containment problem, is solved in polynomial time. We first discuss applications that replace the containment problem with the homomorphism problem, and maintaining homomorphism information among XPath patterns will benefit those applications. Then, we propose a lattice structure, called POX (Partially Ordered Set of XPath Patterns), and develop algorithms for maintaining it. As our analyses show, the algorithms can efficiently maintain POX in polynomial time.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.10
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• pp.2217-2223
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• 2012

As smartphone users are over 20 million, companies, which offer cloud computing services, try to support various mobile devices. If so, users can use the same cloud computing service using mobile devices, as sharing document. When user share the work, there are problem in configuration management, data confidentiality and integrity. In this paper, we propose a method that cloud computing users share document efficiently, edit encrypted docuements, and manage configuration based on homomorphic encryption, which integrity is verifiable.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.4
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• pp.909-916
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• 2013

Since realization of E-voting system expands participation of voters and efficient count of voting, political and social and technical revolution is possible. However, without secure e-voting system, practical usages are infeasible. In the paper, we propose an e-voting system which is able to open votes in server without decryption during midst process using EC-ELGAMAL homomorphic cryptography. Users ensure anonymity with pseudo id from server and check their voting with Bloom Filter technology. Furthermore, we combine attributes and voters' information, so we can collect information of voter under the condition of anonymity.

• The KIPS Transactions:PartC
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• v.15C no.6
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• pp.447-454
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• 2008

In this paper, we propose new technique which uses the fingerprint features in order to generate one time passwords(OTPs). Fingerprint is considered to be one of the powerful personal authentication factors and it can be used for generating variable passwords for one time use. Also we performed a simulation of homomorphic graph variable of fingerprint feature point using dendrogram and distribution of fingerprint feature points for proposed password generation method.

• Convergence Security Journal
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• v.14 no.2
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• pp.51-56
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• 2014

Be expressed in network-centric warfare, mainly battlefield environment of the future. The purpose of the system for the war of the future, is to recognize the enemy before the enemy, and rapid decision-making, to hit accurately. For this reason, it is during the construction of the integrated system of C4ISR+PGM. In such an integrated system, it is necessary to further enhance the security aspects of the information. In particular, strengthening of security leads to a decrease of efficiency. Therefore, security and efficiency should be considered together. In this study, we provide a homomorphic encryption system that can be safely managed information environment on the battlefield of the future. The proposed method uses encryption technology of homomorphic that can be the arithmetic operations on encrypted state. It has changed from the state of the encryption. Therefore, the attacker can not know a decent information.

• Review of KIISC
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• v.19 no.3
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• pp.80-89
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• 2009

최근 정보보호 패러다임은 네트워크 보안에서 데이터베이스 보안으로 진화되고 있는 가운데 데이터베이스의 관리 및 운용을 외부사업자에게 위탁하는 데이터베이스 아웃소싱 서비스(DAS, Database As a Service)가 활성화되고 있다. 이러한 가운데 포털사이트나 기업내 데이터베이스에 저장된 데이터 유출이나 도난의 위험성이 증가되고 있다. 본 논문에서는 DAS 모델 환경에서 암호화 데이터의 효율적인 연산이 가능한 준동형 암호 방식을 검토한다. 또한 본 논문에서는 Generalized Paillier 암호방식을 암호화된 개인 의료데이터의 연산에 적용한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.5
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• pp.428-433
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• 2013

We present a fully homomorphic encryption (FHE) scheme without key switching based on ring- learning with errors (RLWE) problems and some other assumption. Previous FHE schemes based on LWE needed a step called key switching to reduce the dimension of ciphertext. The key switching step actually needs a heavy computation and severe increasement of keys. So the key switching step is a big burden for implementing FHE Schemes. We suggest a FHE scheme without key switching step by reducing the dimension of ciphertexts in other way. Instead of throwing away key switching, we need another hardness assumption of the difficulty of solving quadratic equation over rings.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.11 no.6
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• pp.105-113
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• 2001

Recently, Gallant, Lambert arid Vanstone introduced a method for speeding up the scalar multiplication on a family of elliptic curves over prime fields that have efficiently-computable endomorphisms. It really depends on decomposing an integral scalar in terms of an integer eigenvalue of the characteristic polynomial of such an endomorphism. In this paper, by using an element in the endomorphism ring of such an elliptic curve, we present an alternate method for decomposing a scalar. The proposed algorithm is more efficient than that of Gallant\`s and an upper bound on the lengths of the components is explicitly given.