• Journal of Digital Convergence
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• v.11 no.9
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• pp.173-179
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• 2013

In a biometric authentication scheme, a user's biometric data that is unique to the user is used to prove the user's identity to the third party. Since the user should have to participate in every authentication sessions, it's not possible to delegate other users to authenticate instead of himself/herself. In a biometric signature scheme, contrary to authentication scheme, a user's biometric data is used to prove that "this message is signed by the signer who claims to be" to the third party. However, once the biometric key is created, it can be accessed by the signer. Thus, it's possible to lend the biometric key to other users. In this study, the server based biometric realtime signature scheme is proposed. The proposed scheme can be applied to sign the vote in electronic voting or to authenticate the copyright owner in DRM enabled mobile commerce where the proxy signatures are not allowed.

• Journal of Digital Convergence
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• v.12 no.1
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• pp.389-395
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• 2014

In a biometric signature scheme, a user's biometric key is used to sign the document. It also requires the user be authenticated with biometric recognition method, prior to signing the document. Because the biometric recognition is launched every time the signature session started, it is not suitable for electronic commerce applications such as shopping malls where large number of documents to sign are required. Therefore, to commercialize biometric based signature schemes, the new proxy signature scheme is needed to ease the burden of the signer. In the proxy signature scheme, the signer can delegate signing activities to trustful third parties. In this study, the biometric based signature delegation method is proposed. The proposed scheme is suitable for applications where a lot of signing are required. It is consisted of biometric key generation, PKI based mutual authentication, signature generation and verification protocols.

• 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 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.