• Proceedings of the Korea Information Processing Society Conference
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• 2017.11a
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• pp.285-288
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• 2017

비식별화 모델은 데이터 공유를 위한 모델로 원본데이터를 비식별화 변환 처리하여 개인정보를 보호함과 동시에 분석에 필요한 데이터를 외부에 제공하는 모델로 연구되어 왔다. 변환 방법으로는 삭제, 일반화, 범주화 기술 등이 주로 사용되며 변환 과정 중에는 재식별 가능성을 최소화하기 위해 k-익명성, l-다양성, t-근접성 혹은 differential privacy 등의 프라이버시 모델이 적용되고 있다. 하지만 변환된 비식별 데이터 세트는 필연적으로 원본 데이터 세트와 다른 값을 가지며 이는 결과적으로 최종 분석 결과에 영향을 주게 된다. 이를 위해 두 데이터 세트 간의 차이를 상이도(dissimilarity) 혹은 정보 손실율(information loss)이라는 지표로 측정 하고 있으며 본 지표는 비식별 데이터의 활용성을 평가 하는 데에 매우 중요한 역할을 한다. 본 연구에서는 비식별 데이터와 원본 데이터와 간의 차이를 도메인 기반의 절대적인 기준대비로 표현한 상이도 측정 방법을 제안하며, 그 유효성을 실데이터 기반의 실험을 통해 검증하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.12
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• pp.3398-3415
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• 2023

Internet-of-Things (IoT) is an emerging technology that interconnects millions of small devices to enable communication between the devices. It is heavily deployed across small scale to large scale industries because of its wide range of applications. These devices are very capable of transferring data over the internet including critical data in few applications. Such data is exposed to various security threats and thereby raises privacy-related concerns. Even devices can be compromised by the attacker. Modern cryptographic algorithms running on traditional machines provide authentication, confidentiality, integrity, and non-repudiation in an easy manner. IoT devices have numerous constraints related to memory, storage, processors, operating systems and power. Researchers have proposed several hardware and software implementations for addressing security attacks in lightweight encryption mechanism. Several works have made on lightweight block ciphers for improving the confidentiality by means of providing security level against cryptanalysis techniques. With the advances in the cipher breaking techniques, it is important to increase the security level to much higher. This paper, focuses on securing the critical data that is being transmitted over the internet by PRESENT using key-based dynamic S-Box. Security analysis of the proposed algorithm against other lightweight block cipher shows a significant improvement against linear and differential attacks, biclique attack and avalanche effect. A novel key-based dynamic S-Box approach for PRESENT strongly withstands cryptanalytic attacks in the IoT Network.

• The Journal of the Korea Contents Association
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• v.20 no.1
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• pp.356-363
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• 2020

As a becoming era of Internet-of-Things, various devices are connected via wire or wirless networks. Although every day life is more convenient, security problems are also increasing such as privacy, information leak, denial of services. Since ECC, a kind of public key cryptosystem, has a smaller key size compared to RSA, it is widely used for environmentally constrained devices. The key of ECC in constrained devices can be exposed to power analysis attacks during scalar multiplication operation. In this paper, a key-randomization method is suggested for scalar multiplication on SECG parameters. It is against differential power analysis and has operational efficiency. In order to increase of operational efficiency, the proposed method uses the property 2^lP=∓cP where the constant c is small compared to the order n of SECG parameters and n=2^l±c. The number of operation for the Coron's key-randomization scalar multiplication algorithm is 21, but the number of operation for the proposed method in this paper is (3/2)l. It has efficiency about 25% compared to the Coron's method using full random numbers.

• The KIPS Transactions:PartB
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• v.12B no.6 s.102
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• pp.671-678
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• 2005

In this paper, we suggest an algorithm that allows us to extract the important obbject from motion pictures and then replace the background with arbitrary images. The suggested technique can be used not only for protecting privacy and reducing the size of data to be transferred by removing the background of each frame, but also for replacing the background with user-selected image in video communication systems including mobile phones. Because of the relatively large size of image data, digital image processing usually takes much of the resources like memory and CPU. This can cause trouble especially for mobile video phones which typically have restricted resources. In our experiments, we could reduce the requirements of time and memory for processing the images by restricting the search area to the vicinity of major object's contour found in the previous frame based on the fact that the movement of major object is not wide or rapid in general. Specifically, we detected edges and used the edge image of the initial frame to locate candidate-object areas. Then, on the located areas, we computed the difference image between adjacent frames and used it to determine and trace the major object that might be moving. And then we computed the contour of the major object and used it to separate major object from the background. We could successfully separate major object from the background and replate the background with arbitrary images.