• Journal of Digital Contents Society
• /
• v.14 no.1
• /
• pp.81-88
• /
• 2013

The increase of the smartphone users has popularized the mobile payment and the mobile credit card users are rapidly getting increased. The mobile credit cards that currently used provide its users with the service through downloading mobile credit card information into USIM. The mobile credit card saved in USIM has the minimized information for the security and is based on PKI. However certificate-based payment system has a complicated procedure and costs a lot of money to manage the certificates and CRL(Certificate Revocation List). Furthermore, It can be a obstacle to develop local e-commerce in Korea because it is hard for foreigners to use them. We propose the secure and efficient mobile credit card payment protocol based on certificateless signcryption which solve the problem of certificate use.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.11 no.12
• /
• pp.2271-2279
• /
• 2007

In this paper, we introduce the notion of certificate-based encryption in multi-receiver environment, which avoids the inherent key escrow problem while preserving the implicit certification in identity-based encryption. We also construct a highly efficient certificate-based encryption scheme for multi-receiver environment, which eliminates pairing computation to encrypt a message for multiple receivers. Moreover, the proposed scheme only needs one pairing computation for decrypting the ciphertext. We compare our scheme with the most efficient identity-based encryption scheme for multi-receiver environment proposed by Baek et.al.[1] in terms of the computational point of view, and show that our scheme provides better efficiency than Baek's scheme. Finally, we discuss how to properly transform our scheme into a new public key broadcast encryption scheme based on subset-cover framework.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.11 no.4
• /
• pp.2254-2275
• /
• 2017

In this paper, we present an IND-CCA2 secure certificateless proxy re-encryption scheme in the random oracle model. A certificateless public key cryptography simplifies the certificate management in a traditional public key infrastructure and the built-in key escrow feature in an identity-based public key cryptography. Our scheme shares the merits of certificateless public key encryption cryptosystems and proxy re-encryption cryptosystems. Our certificateless proxy re-encryption scheme has several practical and useful properties - namely, multi-use, unidirectionality, non-interactivity, non-transitivity and so on. The security of our scheme bases on the standard bilinear Diffie-Hellman and the decisional Bilinear Diffie-Hellman assumptions.

• Annual Conference of KIPS
• /
• 2005.05a
• /
• pp.1461-1464
• /
• 2005

In contrast with conventional networks, mobile ad hoc networks usually do not provide online access to trusted authorities or to centralized servers, and they exhibit frequent partitioning due to link and node failures and node mobility. For these reasons, traditional security solutions that require online trusted authorities or certificate repositories, but those are not well-suited for securing ad hoc networks. Moreover, a fundamental issue of securing mobile ad hoc networks is to ensure mobile nodes can authenticate each other. Because of its strength and efficiency, public key and digital signature is an ideal mechanism to construct the authentication service. Although this is already mature in the internet application, providing public key based authentication is still very challenging in mobile ad hoc networks. In this paper I propose a secure public key authentication service based on clustering model and trust model to protect nodes from getting false public keys of the others efficiently when there are malicious nodes in the network.

• Journal of the Korea Society of Computer and Information
• /
• v.4 no.4
• /
• pp.9-14
• /
• 1999

The authentication technique, which uses public key cryptographic algorithms, proves itself by generating authentication value through secret keys and gives verification by means of public keys .This paper is believed to 1) solve the problem of distribution and management of secret keys, which still remain the problem of authentication used in symmetric cryptographic algorithm. 2) provide the method to receive a certificate of handling the problems of public key lists through the authentication authority. and finally 3) suggest an algorithm which will enable us to run the public keys more effectively.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2009.10a
• /
• pp.359-362
• /
• 2009

Qualified certificates in online financial and security transaction area are currently used for authentication of the user. The authorized user's public key certificates are stored in binary; the private key corresponding to the user's public key certificates is encrypted by the user password, and then is stored in a file. But the present management system to access the public certificates in local has some problems. In this study, we propose that the mobile public certificate management application to avoid the exist problems.

• Health Policy and Management
• /
• v.21 no.2
• /
• pp.329-348
• /
• 2011

This research analyzed 168,010 cases of death of the aged over 65 from 244,867cases of death excluding 7 unknown age cases from 244,874 all age cases of death by using the death data of the National Statistical Office for 2007 to figure out factors affecting the quality of causes of death statistics of the aged and to suggest the ways of improving the quality of death statistics of the aged in korea. This research tried to derive factors affecting ill-defined cause of death category in acordance with WHO's guidelines and to find causes of lowering the accuracy of causes of death statistics of the aged. This research identified the problems of causes of death statistics of the aged by using both demographic characteristics such as sex, age, marital status, educational attainment, residential region, region size and factors of death items as independent variable to find causes of ill-defined cause of death of the aged. Logistic regression analysis was executed to calculate the hazard ratio about the ill-defined causes of death of the aged and multiple regression analysis was conducted to derive factors affecting the ill-defined cause of death by regional groups through using these independent variables such as the component ratio of over age 65, female death rates, doctors insitutions rate, medical institutions rate, attaching rates of death certificate by neighborhood. As a results of this research, R-code was the highest of ill-defined causes of death, accounting for 82.1%, and senility death(R54) of R-code was the highest, accounting for 91.2%. through subdivided order distribution of the ill-defined causes of death of the aged. As ill-defined causes of death by regional groups, attaching rates of death certificate by neighborhood was the most important factor(p<0.05) and also showed regression model's description with 83.8% ($R^2$=83.8%). Furthermore, Jeon-nam was the highest in the regional groups and these regions such as Je-ju, Jeon-buk, Chung-nam were not only attaching the death certificate by neighborhood but also were high at the rate of ill-defined causes of death. Therefore, this research found that both reconsideration about death certificate by neighborhood and education for doctors who write death certificate were needed the most.

• The KIPS Transactions:PartC
• /
• v.10C no.6
• /
• pp.793-798
• /
• 2003

The P2P service is a technology that can share their information with each other who is able to be connected ith a relating program without passing by a server. Since all personal compiters that linked to the internet under the P2P service can opetate as server or a client, they can provide and share both their information and services through the direct connection. Currently, the P2P service is giving an equal privilege to all users for sharing their resources,.Under this situation, a lot of vulnerability against the various sttacks through the Unternet is possoble, more sophisticated security services are necessary. In this paper, We propose and access control schemae using SPKI(Simple Public Key Infrastructure). The scheme designates and access and acces control by providing the certificate to users who request a connection for resource sharing and limits the resource usage of information provider according to the access right that is given to their own rights.

• Journal of Korean Public Health Nursing
• /
• v.17 no.1
• /
• pp.17-25
• /
• 2003

This study aimed to investigate predictors of turnover intention of home visiting nurses at 16 public health centers in Busan. There are two groups of independent factors: non-work related(i. e., age, educational level, working duration as nurses in hospitals, and certificate), and work related factors(i. e., working duration as nurses in public health centers, working duration as home visiting nurse, position, number of households visited per week, workload, cooperation among staff, support by supervisors, supply of vehicles, and supply of materials). Data were collected with self-administrated questionnaires which consisted of 4 items of non-work related factors, 9 items of work related factors, and 1 item of turnover intention to other department. Data were analyzed using an univariate logistic regression and multiple logistic regression. According to the results, heavy workload (Yes vs No, OR=4.31, $95\%$ CI=1.16-16.04) was the most powerful predictor on the turnover intention. In conclusion. this result was similar to those of other studies on the predictors of turnover intention of clinical nurses at hospitals. To decrease the turnover intention among home visiting nurses at public health centers in Busan, alleviating the workload is needed.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
• /
• 2006.06a
• /
• pp.176-180
• /
• 2006

In this paper, we propose an efficient authentication protocol based on certificateless signature scheme, which does not need any infrastructure to deal with certification of public keys, among the vehicles in Vehicular Ad-hoc Networks. Moreover, the proposed protocol introduces the concept of interval signature key for efficiently solving the problem of certificate revocation.