• Journal of the Korea Institute of Information Security & Cryptology
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• v.13 no.6
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• pp.55-65
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• 2003

To perform the certificate validation processing on the user-side application induces the very considerable overhead because of the complex and time-consuming characteristic of the validation processing. Especially, the verification for digital signature over a certificate can be the major reason of the overhead, since the verification accompanies with the cryptographic calculation over each certificate on the certificate path. In this paper, we propose a new certificate validation scheme can reduce the overhead caused by user-side certificate validation processing and improve the utilization of CAs. As the result, our proposed scheme can not only reduces the overhead for the validation processing by decreasing the cryptographic calculation but also improves the utilization of CAs by employing them to the validation processing.

• Journal of Digital Convergence
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• v.12 no.2
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• pp.243-248
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• 2014

The demand for messenger service goes on growing rapidly with widespread use of smartphones. Generally, the smartphone messenger provides group communication functions in which users can make the group and communicate with each other. In the mobile meeting, the attendees can participate in the meeting with use of smartphone messengers wherever they are. To make the mobile meeting put to practical use, the mobility and privacy should be ensured to attendees. To satisfy the mobility requirement, the user which is not belong to the group members should not be able to participate in the meeting. To ensure the privacy requirement, the attendees should have not to repudiate the meeting results. In this study, the mobile meeting authentication scheme is proposed which provides mobility and privacy. The proposed scheme consists of meeting group creation, group key generation, group signature and verification protocols. All attendees should have to participate in the signature verification because it is based on the challenge-response type protocol. Thus, it's not possible to collude with malicious attendees to change the meeting results.

• Convergence Security Journal
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• v.6 no.2
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• pp.13-20
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• 2006

Since the domestic internet banking environment has established for Microsoft Internet Explorer (IE), the internet banking service is not able to use in the open operating system and web browser such as linux and freeBSD. To solve the :problem, we develop the digital signature system used the seed for the digital payment system in the open software environment. Because the domestic internet banking performs the certificate and digital signature verification through official certificate that the official certificate authority issues, we analyze and develop the verification of validity system for the official certificate. Since the virtual internet banking environment is already established in the web server developing under the self-abilities, the basic internet banking service can be performed installing the certificate in the client which has the mozilla porting the seed. Finally, we can confirm that the certificate and digital signature are performed normally through the experiment.

• Journal of Korean Society of Archives and Records Management
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• v.20 no.3
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• pp.1-21
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• 2020

Although the National Archives of Korea has been receiving transfer of standard electronic documents with a retention period of more than 30 years from the central administration since 2015, errors and inefficiencies persist. Despite this, however, there remain no studies that analyze or address these issues. This study aims to bridge this gap and found that most errors in the transfer process occur at the production stage. To address such, this study proposes a four-step solution. First, before electronic document approval, the text and attached files are checked for defects to prevent errors. Second, as soon as the signature is made, digital signatures are applied on a file-by-file basis to ensure integrity. Third, integrity verification and transfer inspection are automatically performed through digital signature investigation and defect check procedure during transfer and preservation. Fourth and last, the criteria of acquiring records and integrity guarantee technologies are properly applied in production stage with proper management and supervision.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.2
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• pp.617-636
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• 2021

This paper presents a privacy-preserving data aggregation scheme deals with the multidimensional data. It is essential that the multidimensional data is rarely mentioned in all researches on smart grid. We use the Paillier Cryptosystem and blinding factor technique to encrypt the multidimensional data as a whole and take advantage of the homomorphic property of the Paillier Cryptosystem to achieve data aggregation. Signature and efficient batch verification have also been applied into our scheme for data integrity and quick verification. And the efficient batch verification only requires 2 pairing operations. Our scheme also supports fault tolerance which means that even some smart meters don't work, our scheme can still work well. In addition, we give two extensions of our scheme. One is that our scheme can be used to compute a fixed user's time-of-use electricity bill. The other is that our scheme is able to effectively and quickly deal with the dynamic user situation. In security analysis, we prove the detailed unforgeability and security of batch verification, and briefly introduce other security features. Performance analysis shows that our scheme has lower computational complexity and communication overhead than existing schemes.

• The Transactions of the Korea Information Processing Society
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• v.7 no.6
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• pp.1903-1910
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• 2000

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 TCP/IP using 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.

• Proceedings of the Korea Database Society Conference
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• 2000.11a
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• pp.343-349
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• 2000

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 TCP/IP using Choquet fuzzy integral compapred 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.

• Proceedings of the Korea Information Processing Society Conference
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• 2001.04a
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• pp.445-448
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• 2001

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 TCP/IP using security continuity management 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.

• Journal of the Korea Convergence Society
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• v.7 no.1
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• pp.49-55
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• 2016

In a delegate authentication, a user can lend his/her own authentication data to the third parties to let them be authenticated instead of himself/herself. The user authentication schemes based on the memory of unique data such as password, are vulnerable to this type of attack. Biometric authentication could minimize the risk of delegate authentication since it uses the biometric data unique by each person. Group authentication scheme is used to prove that each group member belongs to the corresponding group. For applications such as an electronic voting or a mobile meeting where the number of group members is changing dynamically, a new group authentication method is needed to reflect the status of group in real time. In this paper, we propose biometric authentication based dynamic group signature scheme. The proposed scheme is composed of biometric key generation, group public key creation, group signature generation, group signature verification and member update protocols. The proposed member update protocol is secure against colluding attacks of existing members and could reflect group status in real time.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.13 no.3
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• pp.111-117
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• 2003

The XTR public key system has advantage of short key length and fast computing speed. So, the XTR is used usefully in complicated operation. In this paper, we propose a new algorithm of double exponentiation operation and a proxy signature protocol based on the XTR. The double exponentiation operation should be executed to apply XTR for the proxy signature protocol. But this algorithm is inappropriate, because two secret key has to be blown in existent operation algorithm. New algorithm enable double exponentiation operation with proxy signer's secret key and public information. And the XTR is used to generation and verification of proxy at proxy signature protocol. Therefore proxy signature based on the XTR has basic advantage of the XTR. These advantage can be used in internet as well as mobile.