• KIPS Transactions on Computer and Communication Systems
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• v.2 no.7
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• pp.311-316
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• 2013

256-bit block cipher XSB(eXtended Spn Block cipher) was proposed in 2012 and has a symmetric strucrure in encryption and decryption process. In this paper, we propose a differential fault analysis on XSB. Based on a random byte fault model, our attack can recover the secret key of XSB by using only two random byte fault injection. This result is the first known cryptanalytic result on the target algorithm.

• The Journal of the Korea Contents Association
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• v.2 no.3
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• pp.80-86
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• 2002

In this paper, we propose the new optical security technique using two phase holograms based on interferometer. The encoded random phase image does not have any information on the original image. Without Hewing the key mask, one cannot decode the encrypted image and regenerate the original image. And the use of two phase only images in the proposed security system leads to maximum optical efficiency (100% in theory). Also they cannot be detected by an intensity detector such as a CCD camera. Computer simulations and optical experiments show performance of the proposed methods.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.602-605
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• 2007

COMS SOC is supposed to operate IDACS as a backup of MSC. For the backup operation, there is a route between SOC and MSC for exchanging current version such as radiometric calibration for IMPS, dissemination schedule, encryption key and conversion table for LHGS. DATS C&M S/W is basically designed to control and monitor DATS equipment. However, its capability is extended to monitor the working status of IMPS, LHGS and even MSC IDACS. In addition, DATS C&M SIW can display discrepancy between MSC and SOC when applied version is different each other. This paper presents detailed description on the development of DATS C&M S/W.

• Journal of the Optical Society of Korea
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• v.4 no.1
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• pp.19-22
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• 2000

A new image encoding and identification scheme is proposed for security verification by us-ing a CGH(computer generated hologram), random phase mask, and a correlation technique. The encrypted image, which is attached to the security product, is made by multiplying a QP- CGH(quadratic phase CGI) with a random phase function. The random phase function plays a key role when the encrypted image is decrypted. The encrypted image can be optically recovered by a 2-f imaging system and automatically verified for personal identification by a 4-f correlation system. Simulation results show the proposed method can be used for both the reconstruction of an original image and the recognition of an encrypted image.

• Journal of Communications and Networks
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• v.4 no.2
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• pp.81-89
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• 2002

In this paper, we design and implement an efficient fair off-line electronic cash system based on Elliptic Curve Discrete Logarithm Problem (ECDLP), in which the anonymity of coins is revocable by a trustee in case of dispute. To achieve this, we employ the Petersen and Poupard s electronic cash system [1] and extend it by using an elliptic curve over the finite field GF($2^n$). This naturally reduces message size by 85% compared with the original scheme and makes a smart card to store coins easily. Furthermore, we use the Baek et al. s provably secure public key encryption scheme [2] to improve the security of electronic cash system. As an extension, we propose a method to add atomicity into new electronic cash system. To the best of our knowledge, this is the first result to implement a fair off-line electronic cash system based on ECDLP with provable security.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04a
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• pp.193-195
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• 2004

브로드캐스트 암호화 기법은 공개된 네트워크 상에서 멀티미디어, 소프트웨어, 유료 TV 등의 디지털 정보들을 전송하는데 적용되고 있다. 브로드캐스트 암호화 기법에서 중요한 것은 오직 사전에 허가된 사용자만이 디지털 정보를 얻을 수 있어야 한다는 것이다. 브로드캐스트 메시지가 전송되면 권한이 있는 사용자들은 자신이 사전에 부여받은 개인 키를 이용하여 먼저 세션키를 복호화하고 이 세션키를 통하여 디지털 정보를 얻게 된다. 이와 같이 사용자는 브로드캐스터가 전송하는 키를 이용하여 메시지나 셰션키를 획득하게 되는데. 이러한 과정에서 브로드캐스터가 키를 생성하고 분배하는 과정이 필요하다. 또한 사용자가 탈퇴나 새로운 가입시에 효율적인 키 갱신이 필요하게 된다. 이에 본 논문에서는 기존에 서버가 단독으로 사용자를 예측하여 사용자에게 키를 분배하는 것이 아니고 초기 중심 서버가 키를 생성 한 후 하부의 서버에 권한위임은 하면 하부 Router는 다시 사용자에게 키를 배포하는 방식으로 키를 생성 분배하도록 한다. 본 제안 방식은 브로드캐스트 암호화의 키 관리와 멀티캐스트 키 관리의 장점을 이용하여 효율적인 키 관리를 제안한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2017.11a
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• pp.182-185
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• 2017

넌어드레스(Non-Addressable) 장비는 IP 주소를 포함한 기타 어느 계정을 갖지 않는 통신 보안 장비로서, 해킹을 포함한 허가되지 않은 공격들로부터 원천적으로 단말을 보안할 수 있다. 본 논문에서는 넌어드레스 장비에서 AES 방식으로 데이터를 암/복호화 시 성능을 향상시키기 위한 방법을 제시한다. AES-128, 192, 256에서의 암/복호화 시간, CPU 사용량, 메모리 사용량, 실제 데이터의 전송속도를 비교하여 최선의 설정 방법을 도출한다.

• Journal of Information Processing Systems
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• v.15 no.6
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• pp.1265-1276
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• 2019

Data deduplication is a common method to improve cloud storage efficiency and save network communication bandwidth, but it also brings a series of problems such as privacy disclosure and dictionary attacks. This paper proposes a secure deduplication scheme for cloud storage based on Bloom filter, and dynamically extends the standard Bloom filter. A public dynamic Bloom filter array (PDBFA) is constructed, which improves the efficiency of ownership proof, realizes the fast detection of duplicate data blocks and reduces the false positive rate of the system. In addition, in the process of file encryption and upload, the convergent key is encrypted twice, which can effectively prevent violent dictionary attacks. The experimental results show that the PDBFA scheme has the characteristics of low computational overhead and low false positive rate.

• ETRI Journal
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• v.32 no.1
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• pp.93-101
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• 2010

A true random number generator (TRNG) is widely used to generate secure random numbers for encryption, digital signatures, authentication, and so on in crypto-systems. Since TRNG is vulnerable to environmental changes, a deterministic function is normally used to reduce bias and improve the statistical properties of the TRNG output. In this paper, we propose a linear corrector for secure TRNG. The performance of a linear corrector is bounded by the minimum distance of the corresponding linear error correcting code. However, we show that it is possible to construct a linear corrector overcoming the minimum distance limitation. The proposed linear corrector shows better performance in terms of removing bias in that it can enlarge the acceptable bias range of the raw TRNG output. Moreover, it is possible to efficiently implement this linear corrector using only XOR gates, which must have a suitable hardware size for embedded security systems.

• 한국게임학회지
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• v.2 no.1
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• pp.23-30
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• 2002

The objective of this paper was to cope with the verification of the message transfer protocol that integrates the electronic signature and the distribution and authentication of Public key in Mobile Game using m-Commerce Choquet fuzzy integral compared with fuzzy integral. They were classified into the security technology, the security policy, the electronic document processing, the electronic document transportation and the encryption and decryption keys in its function. The measures of items of the message security protocol were produced for the verification of the implemented document in every function.