• Journal of Intelligence and Information Systems
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• v.9 no.2
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• pp.39-50
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• 2003

Deleting unsolicited email, popularly known as spam mail, is an annoying task for Internet users. Moreover, spam mail causes a variety of social problems. At present, legal restrictions cannot eradicate spam senders. As a result, many technical methods to eliminate spam mail such as spam filtering and online stamps have been introduced. However, the process of blocking spam mail can inadvertently result in suspension of indispensable or beneficial communication. In this paper, we propose a certificate and agent based emailing architecture that can block spam mail, while at the same time approve certified mail. This architecture can be accelerated by synergistic utilization of digital signature and electronic document interchange.

• Journal of Korea Society of Industrial Information Systems
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• v.18 no.4
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• pp.43-51
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• 2013

This paper proposes the design of protocol management system for aggregationg messages based on certification between vehicles which not only prevents the messages between vehicles from being forged and altered by Sybil attack by authenticating the them, and but also provides the efficient communication by aggregating the redundant vehicle messages which frequently happens when communicating. For this, the proposed system proposes the SKLC(Session Key Local Certificate) design which is a local certificate based on a session key, and the MAP(Message Aggregation Protocol) design which aggregates the redundant vehicle messages. Therefore, when the proposed system checks the certificate of vehicle, it provides the reliable information securely by verifying the integrity of vehicle with a hash function operation, and improves communication efficiency by reducing the processing time.

• ETRI Journal
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• v.38 no.4
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• pp.724-734
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• 2016

To achieve confidentiality, integrity, authentication, and non-repudiation simultaneously, the concept of signcryption was introduced by combining encryption and a signature in a single scheme. Certificate-based encryption schemes are designed to resolve the key escrow problem of identity-based encryption, as well as to simplify the certificate management problem in traditional public key cryptosystems. In this paper, we propose a new certificate-based signcryption scheme that has been proved to be secure against adaptive chosen ciphertext attacks and existentially unforgeable against chosen-message attacks in the random oracle model. Our scheme is not based on pairing and thus is efficient and practical. Furthermore, it allows a signcrypted message to be immediately verified by the public key of the sender. This means that verification and decryption of the signcrypted message are decoupled. To the best of our knowledge, this is the first signcryption scheme without pairing to have this feature.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.1
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• pp.437-454
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• 2020

According to the privacy regulations of the health insurance portability and accountability act (HIPAA), patients' control over electronic health data is one of the major concern issues. Currently, remote access authorization is considered as the best solution to guarantee the patients' control over their health data. In this paper, a new biometric-based key management scheme is proposed to facilitate remote access authorization anytime and anywhere. First, patients and doctors can use their biometric information to verify the authenticity of communication partners through real-time video communication technology. Second, a safety channel is provided in delivering their access authorization and secret data between patient and doctor. In the designed scheme, the user's public key is authenticated by the corresponding biometric information without the help of public key infrastructure (PKI). Therefore, our proposed scheme does not have the costs of certificate storage, certificate delivery, and certificate revocation. In addition, the implementation time of our proposed system can be significantly reduced.

• Journal of information and communication convergence engineering
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• v.2 no.2
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• pp.128-131
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• 2004

We suggest resource authorization system based on RBAC admitting someone to access resources. In existing grid environment, The authorization mechanism on user's resource is to give users an authority on the basis of DN(Distinguished Name) of proxy certificate and map file mapped in local system ID by one-to-one. In this case, it is difficulty in resource management such as each accounting management, memory resource, and disk resource, if the number of users, who want to use them is increased. To solve this problem, we specify the role of user's task in extension fields of his proxy certificate instead of the authorization mechanism of user's ID and propose resource authorization system being able to access his resource.

• ETRI Journal
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• v.39 no.1
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• pp.135-144
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• 2017

Recently, mobile phones have been recognized as the most convenient type of mobile payment device. However, they have some security problems; therefore, mobile devices cannot be used for unauthorized transactions using anonymous data by unauthenticated users in a cloud environment. This paper suggests a mobile payment system that uses a certificate mode in which a user receives a paperless receipt of a product purchase in a cloud environment. To address mobile payment system security, we propose the transaction certificate mode (TCM), which supports mutual authentication and key management for transaction parties. TCM provides a software token, the transaction certificate token (TCT), which interacts with a cloud self-proxy server (CSPS). The CSPS shares key management with the TCT and provides simple data authentication without complex encryption. The proposed self-creating protocol supports TCM, which can interactively communicate with the transaction parties without accessing a user's personal information. Therefore, the system can support verification for anonymous data and transaction parties and provides user-based mobile payments with a paperless receipt.

• Management & Information Systems Review
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• v.15
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• pp.165-186
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• 2004

When certificates of qualification relating to computer have shown up like dam water and meeting the age of office automation (OA) utilizing computer throughout the community, and at the point of time when the promotion of efficiency of duty is attempted by utilizing internet, the improvement plans should be groped for to expect to cultivate the national industrial manpower efficiently and by easily approaching the related OA certificates of qualification related to computer so that everyone can acauire the additional points for recognition of credit, entering company and promotion by the dimension of public trust, recognition degree, practial using level in actual affairs, reliability of problems and after manpower management of the certificates of qualification less expensively and saving time. the concrete plans are as follows: First, in the standard of making questions for the examination of 'Computer Utilizing Ability' executed by the chamber of commerce and Industry, there is the independent examination, but by inserting the presentation portion in the higher grade and middle grade, it should be contributed to improve office efficiency both in mane and reality. Second, though the internet retriever's examination is executed by the nongovernment specialized examination, since it is actually widely utilized in the office activities due to universality of using internet, it is now the time to newly establish and accommodate it as the national examination of 'internet Utilizing Ability', not the interest specialized retriever. Third, the applicants, shall take examination for the nongoverment certificate of qualification or enterprise's certificate of qualification at the date and place designated by the applicant, but there are much restrictions for the national certificate of qualification, so the date of examination shall be decided flexibly and efficiently to give chances to students by adjusting to the semesters of the students. Fourth, in this rapidly changing age of the informationalization community, the acquisition of the certificates of qualification through the university and the designated and entrusted educational institutes should be increased the proportion of activation to become officially recognized, and the extent of special treatment for obtainers of the certificate of qualification should be expanded to equip manpower competitive power in the age of informationalization.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.12
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• pp.3352-3365
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• 2012

Group key agreement (GKA) is a cryptographic primitive allowing two or more users to negotiate a shared session key over public networks. Wu et al. recently introduced the concept of asymmetric GKA that allows a group of users to negotiate a common public key, while each user only needs to hold his/her respective private key. However, Wu et al.'s protocol can not resist active attacks, such as fabrication. To solve this problem, Zhang et al. proposed an authenticated asymmetric GKA protocol, where each user is authenticated during the negotiation process, so it can resist active attacks. Whereas, Zhang et al.'s protocol needs a partially trusted certificate authority to issue certificates, which brings a heavy certificate management burden. To eliminate such cost, Zhang et al. constructed another protocol in identity-based setting. Unfortunately, it suffers from the so-called key escrow problem. In this paper, we propose the certificateless authenticated asymmetric group key agreement protocol which does not have certificate management burden and key escrow problem. Besides, our protocol achieves known-key security, unknown key-share security, key-compromise impersonation security, and key control security. Our simulation based on the pairing-based cryptography (PBC) library shows that this protocol is efficient and practical.

• Journal of Communications and Networks
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• v.6 no.2
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• pp.156-162
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• 2004

In recent years, mobile ad-hoc networks have received a great deal of attention in both academia and industry to provide anytime-anywhere networking services. As wireless networks are rapidly deployed, the security of wireless environment will be mandatory. In this paper, we describe a group key management architecture and key agreement protocols for secure communication in mobile ad-hoc wireless networks (MANETs) overseen by unmanned aerial vehicles (UAVs). We use implicitly certified public keys method, which alleviates the certificate overhead and improves computational efficiency. The architecture uses a two-layered key management approach where the group of nodes is divided into: 1) Cell groups consisting of ground nodes and 2) control groups consisting of cell group managers. The chief benefit of this approach is that the effects of a membership change are restricted to the single cell group.

• The KIPS Transactions:PartC
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• v.12C no.3 s.99
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• pp.317-322
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• 2005

The existing certificate based authentication or identification just verifies whether the owner of private key corresponding to public key of certificate is the DN user set in the user field in the certificate or not, then we cannot find out who is the actual private key owner in a real world. To make up for this weak points, the method to insert the identification number like the resident registration number into the certificate extension field is applied as a technical standard to current domestic PKI system. In this paper, we propose the ECC based integrated identification, identification number checking and key management protocol providing user validation during the login.