• Journal of Broadcast Engineering
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• v.21 no.3
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• pp.412-424
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• 2016

Broadcast encryption (BE) is a cryptographic primitive that enables a sender to broadcast a message to a set of receivers in a secure channel. The efficiency of BE is measured by three factors: ciphertext transmission cost, user storage cost, and computational cost for decryption. In general, BE is applied to the environments where a large number of receivers should be accommodated, so that the transmission cost is considered as being the most important factor. In this paper, we suggest a new BE system, using Shamir's secret sharing method, which considerable reduces the transmission cost. In comparison to the previous Subset Difference (SD) system, the transmission size of our BE is longer until $r{\leq}\sqrt{n}$, but get shorter when $r{\geq}\sqrt{n}$ for number of revoked users and n number of total users. We show that the advantage can be achieved at the slight expense of both the storage and computational costs.

• Annual Conference of KIPS
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• 2013.11a
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• pp.842-844
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• 2013

범죄예방이나 위급사항에 대한 대응 등 CCTV의 다양한 필요성에 따라 CCTV를 통합관리하는 CCTV 통합관제 센터가 늘어나고 있다. 행정안전부는 2015년까지 전국 시군구에 CCTV 통합관제센터 구축을 추진하고 있어 앞으로도 계속적으로 증가할 예정이다. 하지만 CCTV관제센터는 증가하고 있음에도 이를 관리할 전문 모니터링 요원이 부족하며, 동시에 이들이 영상정보를 개인의 호기심이나 이득을 위해 사용하는 일이 발생 할 수 있다. 본 논문을 Shamir's Secret Sharing 방법을 이용하여 암호화된 키를 분배하고 요청에 따라 일정 수 이상의 분배키가 모이면 영상 열람권한을 주는 방식으로 설계 하여 관리자가 임의로 영상정보에 접근하는 상황을 방지하였다. 또한 암호키와 랜덤한 값을 이용한 세션키 생성 등을 통해 다양한 보안위협에도 대응하였다.

• The Transactions of the Korea Information Processing Society
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• v.13 no.10
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• pp.475-480
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• 2024

As Internet of Things (IoT) technology is being used in all industries, the importance of secure and convenient firmware update technology is increasing. However, conventional FOTA (Firmware Over-The-Air) technology has a problem because the security is weak when updating firmware with a single path, and strong encryption technology cannot be utilized. Therefore, this study proposes a secure FOTA (S-FOTA) mechanism for lightweight IoT and adaptive S-FOTA ARQ (Automatic Repeat Request) mechanism. This adaptive S-FOTA ARQ mechanism considers the case where the original file cannot be recovered because of the increase in lost files due to the congested channel state and compares and analyzes the conventional method in terms of security, complexity, and transmission speed. Experimental results show that S-FOTA with 40 encrypted files reduced the attacker's attack success rate by at least 62.58% and up to 99.99%, and S-FOTA with 40% of the total number of encrypted file segments takes at least 996.39% more time on average and up to 3374.99% more time than conventional FOTA. In addition, the transmission speed of the adaptive S-FOTA ARQ mechanism was at least 63.16% and up to 2736.36% higher than that of the conventional S-FOTA, and at least 53.89% and up to 70.89% higher than that of the conventional ARQ mechanism.