• Journal of the Korea Society of Computer and Information
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• v.16 no.2
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• pp.201-206
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• 2011

With the development and supply of digital displayers, there has been a heightened interest of late in digital photo frames, eclipsing the existing print frames. This digital photo frame was developed into a new LCD digital photo frame that can be used not only for data display but also as a surveillance monitoring equipment when combined with a CCD camera. The developed photo frame uses a one-way communication encryption method that replaces the existing two-way communication encryption method to ensure the security of the surveillance image data. This method uses the chaotic signal's one-way synchronization phenomenon, where synchronization is made for a certain amount of time, after which the synchronized data can be encrypted and decoded at any point. It can yield the same results as the two-way communication encryption method. Moreover, if the proposed method is applied to the close-range communication methods of ubiquitous devices, it will be able to obtain more efficient results.

• Proceedings of the Korean Society of Computer Information Conference
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• 2014.07a
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• pp.85-86
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• 2014

암호화란 데이터 전송할 때 타 기관 및 타인에 의한 위법적이고 불법적인 방법에 의하여 데이터 일부가 손실되거나 완전히 변경되는 것을 방지하기 위해 데이터를 기술적으로 변환하여 전송하는 방법이다. 본 논문에서는 중요한 데이터나 정보를 전송하거나 이를 저장 할 때는 반드시 이 정보의 기밀성과 무결성을 보장하여 처리해야 한다는 것을 강하게 나타내고 있다. 이러한 암호화는 전송하는 방항에 따라서 단방향 및 양방향 암호화를 적용한다. 또한 암호화 키는 안전성이 확보 되어야 하며 쉽게 해독되어서는 안된다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.221-222
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• 2014

This paper suggests that confidentiality and integrity of information should be guaranteed when transmitting and storing important information in encryption. Encryption should consider both one-way encryption and two-way one and that encryption key should assure security.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.187-188
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• 2014

Encryption is the process of encoding messages or information in such a way that only authorized parties can read it. Encryption doesn't prevent hacking but it reduces the likelihood that the hacker will be able to read the data that is encrypted. Important information (data) information during transmission or storage of the confidentiality, integrity should be guaranteed. Encryption is one-way and two-way encryption is applied. The encryption key must be guaranteed safety.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.14 no.6
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• pp.3-13
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• 2004

Kvarnstrom et al. ${in}^{[10]}$ proposed a rule protection scheme by using one-way hash function to protect rules in security systems over ubiquitous environment. Son et at. ${in}^{[5-6]}$ also prooposed a rule protection scheme for Snort, which is one of the most common IDS. These schemes provide security only for the header information but not for its contents. To solve this problem, this paper presents a scheme based on the symmetric cryptosystem over Snort not only for the header information but also contents. This paper uses the key management based on PCMCIA security module proposed ${by}^{[12]}$ for the symmetric cryptosystem. Our scheme could be adjusted to other security systems, which use the rule based detection.

• Proceedings of the Korean Information Science Society Conference
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• 2002.10e
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• pp.592-594
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• 2002

Mobile IPv6는 호스트에 이동성을 제공하여주는 Mobile IPv4의 부족한 주소문제를 해결하고자 제안된 차세대 프로토콜이다. 본 논문에서는 Mobile IPv6의 이동노드와 메시지인증을 위한 단방향 공개키 암호화 기법과 비밀키 기법을 제안한다. 제안된 프로토콜은 이동노드의 인증과 메시지 인증을 위하여 공개키 암호화 기법을 최소화하였으며, 또한 전송 메시지를 최소화함으로 해서 이동노드의 부담을 줄이도록 설계하였다.

• Proceedings of the Korea Multimedia Society Conference
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• 2001.11a
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• pp.666-670
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• 2001

기존의 리눅스 패스워드 인증 시스템에서는 사용자의 계정을 만들어 처음으로 로그인하여 패스워드를 생성할 때에는 사용자의 프로세스 번호와 패스워드를 생성한 시각에 해당하는 값을 seed로 하여 난수를 발생시켜서 salt값을 만든다. 이 salt값은 사용자가 서로 같은 암호를 사용할 경우 암호가 같은 값으로 저장되는걸 막기 위해서 사용하는데 시스템은 salt값과 사용자 패스워드를 단방향 DES 알고리즘을 사용하여 패스워드 파일을 암호화하여 저장한다. 그러나 패스워드 파일에 사용자암호는 암호화되어 저장되지만, salt값이 그대로 저장되기 때문에 패스워드 파일을 가져가게 된다면 사전공격 해킹툴인 John-the-ripper나 Crack 프로그램 등을 이용하여 쉬운 패스워드는 공격자에 의해 간단하게 풀려버린다. 이러한 사전공격에 대한 취약점을 해결하기 위해 암호화된 사용자 패스워드들을 시스템의 또 다른 비밀키를 사용하여 암호화하는 방법을 도입함으로써 사전공격에 강한 패스워드 인증 시스템을 설계 및 구현한다.

• Journal of the Korea Society of Computer and Information
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• v.19 no.9
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• pp.85-91
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• 2014

Encryption is a method to convert information to no-sense code in order to prevent data from being lost or altered by use of illegal means. Audit logging creates audit log of users' activities, exceptions, and information security events, and then conserves it for a certain period for investigation and access-control auditing. Our paper suggests that confidentiality and integrity of information should be guaranteed when transmitting and storing important information in encryption. Encryption should consider both one-way encryption and two-way one and that encryption key should assure security. Also, all history related to electronic financial transactions should be logged and kept. And, it should be considered to check the details of application access log and major information. In this paper, we take a real example of encryption and log audit for safe data transmission and periodic check.

• Convergence Security Journal
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• v.15 no.5
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• pp.3-8
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• 2015

Most mobile cloud computing system use public key cryptography to provide data security and mutual authentication. A variant of traditional public key technologies called Identity-Based Cryptography(IBC) has recently received considerable attention. The certificate-free approach of IBC may well match the dynamic qualities of cloud environment. But, there is a need for a lightweight secure framework that provides security with minimum processing overhead on mobile devices. In this paper, we propose to use hierarchical ID-Based Encryption in mobile cloud computing. It is suitable for a mobile network since it can reduce the workload of root Public Key Generators by delegating the privilege of user authentication and private key generation. The Identity-Based Encryption and Identity-Based Signature are also proposed and an ID-Based Authentication scheme is presented to secure data processing. The proposed scheme is designed by one-way hash functions and XOR operations, thus has low computation costs for mobile users.

• Journal of KIISE:Information Networking
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• v.37 no.5
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• pp.327-338
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• 2010

Complete Subtree scheme(CS) is a well known broadcast encryption scheme to perform group rekeying in a stateless manner. However, statelessness comes at a cost in terms of storage and message overhead in transmitting key material. We propose a Merged Complete Subtree scheme(MCS) to reduce the communication overhead. It is more practical to make broadcast encryption schemes in network environments with limited bandwidth resources. We define all possible subset unions for ever two subsets of CS as new subsets having own key. The modification causes more storage overhead. Nevertheless, it is possible to make the size of a header, including key materials, half using subset unions of MCS, because the size of a header depends on the number of used subsets. Our evaluation therefore shows that the proposed scheme significantly improves the communication overhead of CS, reducing by half the rekey communication cost. The proposed scheme has the advantage of rekey communication cost when the number of revoked users is significant percentage of the number of potential users. The proposed scheme is fully collusion resistant.