• Journal of Industrial Convergence
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• v.21 no.9
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• pp.49-56
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• 2023

ID is used as identifying information and password as user authentication for ID-based authentication. In order to have a secure user authentication, the password is generated as a hash value on the client and sent to the server, where it is compared with the stored information and authentication is performed. However, if even one character is incorrect, the different hash value is generated, authentication will be failed and cannot be performed and various functions cannot be applied to the password. In this study, we generate several hash value including imaginary number of entered password and transmit to server and perform authentcation. we propose a technique can grants the right differentially to give various rights to the user who have many rights by one account. This can defend shoulder surfing attack by imaginary password and provide convenience to users who have various rights by granting right based on password.

• Convergence Security Journal
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• v.4 no.3
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• pp.19-25
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• 2004

This research develops an algorithm using image synthesis for a server to authenticate users and implements it. The server creates cards with random dots for users and distribute them to users. The server also manages information of the cards distributed to users. When there is an authentication request from a user, the server creates a server card based on information of the user' s card in real time and send it to the user. Different server card is generated for each authentication. Thus, the server card plays a role of one-time password challenge. The user overlaps his/her card with the server card and read an image(eg. a number with four digits) made up from them and inputs the image to the system. This is the authentication process. Keeping security level high, this paper proposes a technique to generate the image clearly and implements it.

• Convergence Security Journal
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• v.12 no.1
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• pp.27-33
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• 2012

VANET(Vehicular Ad-hoc Network) is a kind of ad hoc networks consist of intelligence vehicular ad nodes, and has become a hot emerging research project in many fields. It provide traffic safety, cooperative driving and etc. but has also some security problems that can be occurred in general ad hoc networks. Also, in VANET, vehiculars sho uld be able to authenticate each other to securely communicate with network-based infrastructure, and their location s and identifiers should not be exposed from the communication messages. This paper explains V2I authentication pr otocol using a hash function that preserves the user privacy. In addition, we analyze the security stability of the V2I authentication protocol using Casper in the formal verification technique. As a result, V2I authentication protocol us ing hash function prove a stability.

• The KIPS Transactions:PartC
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• v.11C no.6 s.95
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• pp.765-772
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• 2004

Multicast communication is simultaneous transmission of data to multiple receivers and saves considerably sender resources and network bandwidth. It has high risk to attack using group address and inherent complexity of routing packets to a large group of receivers. It is therefore critical to provide source authentication, allowing a receiver to ensure that received data is authentic. In this paper, we propose the multiple chain authentication scheme for secure and efficient multicast stream. To evaluate the performance of our scheme, we compare our technique with two other previously proposed schemes using simulation results. Our scheme provides non-repudiation of origin, low overhead by amortizing the signature operation over multiple packets, and high packet loss resistance.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.9
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• pp.4560-4575
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• 2018

Since smartphone contains various personal data, security is one of the important aspects in smartphone technologies. Up to now, various authentication techniques have been proposed to protect smartphones. The pattern lock on the Android system is one of the most widely used authentication methods for low-cost devices but it is known to be vulnerable to smudge attack or shoulder surfing attack. LG's smartphone uses its own technique, which is called "Knock Code." The knock code completes the authentication by touching the user defined area in turn on the screen. In this paper, we propose the new, enhanced version of knock code by adding the sliding operation and by using flexible area recognition. We conducted security analysis, which shows that under the same password size, the search space is overwhelmingly larger than the original algorithm. Also, by using the sliding operation, the proposed scheme shows resilience against smudge attacks. We implemented the prototype of our scheme. Experimental results show that compared with the original Knock Code and Android pattern lock, our scheme is more convenient while providing better security.

• KIPS Transactions on Computer and Communication Systems
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• v.7 no.5
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• pp.127-136
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• 2018

In this paper, we propose a PIN entry method that combines with machine learning technique on smartphone. We use not only a PIN but also touch time intervals and locations as factors to identify whether the user is correct or not. In the user registration phase, a remote server was used to train/create a machine learning model using data that collected from end-user device (i.e. smartphone). In the user authentication phase, the pre-trained model and the saved PIN was used to decide the authentication success or failure. We examined that there is no big inconvenience to use this technique (FRR: 0%) and more secure than the previous PIN entry techniques (FAR : 0%), through usability and security experiments, as a result we could confirm that this technique can be used sufficiently. In addition, we examined that a security incident is unlikely to occur (FAR: 5%) even if the PIN is leaked through the shoulder surfing attack experiments.

• Journal of Korea Society of Digital Industry and Information Management
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• v.11 no.3
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• pp.69-77
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• 2015

MANET is composed of only the mobile nodes have a limited transmission range. The dynamic topology by the frequent movement of nodes makes routing difficult and is also cause exposed to security vulnerabilities. In this paper, we propose the security routing technique consisted of mechanism of two steps in order to respond effectively to attack by the modification of the routing information and transmit secure data. The hierarchical structure is used and the authentication node that issues the key of the nodes within each cluster is elected in this proposed method. The authentication node manages key issues and issued information for encrypting the routing information from the source node. The reliability value for each node is managed to routing trust table in order to secure data transmission. In the first step, the route discovery is performed using this after the routing information is encrypted using the key issued by the authentication node. In the second step, the average reliability value of the node in the found path is calculated. And the safety of the data transmission is improved after the average reliability value selects the highest path. The improved performance of the proposed method in this paper was confirmed through comparative experiments with CBSR and SEER. It was confirmed a better performance in the transmission delay, the amount of the control packet, and the packet transmission success ratio.

• Journal of Korea Society of Digital Industry and Information Management
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• v.10 no.3
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• pp.161-169
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• 2014

Wireless Ad Hoc Network is suitable for emergency situations such as and emergency, disaster recovery and war. That is, it has a characteristic that can build a network and use without help of any infrastructure. However, this characteristic is providing a cause of many security threats. In particular, routing attack is not applied the existing routing methods as it is and it is difficult to determine accurately whether nodes that participate in routing is malicious or not. The appropriate measure for this is necessary. In this paper, we propose a secure routing technique through a zone architecture-based node authentication in order to provide efficient routing between nodes. ZH node is elected for trust evaluation of the member nodes within each zone. The elected ZH node issues a certification of the member nodes and stores the information in ZMTT. The routing involvement of malicious nodes is blocked by limiting the transfer of data in the nodes which are not issued the certification. The superior performance of the proposed technique is confirmed through experiments.

• Journal of Internet Computing and Services
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• v.7 no.5
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• pp.33-41
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• 2006

Wireless LAN is intrinsically weak in security of transmissions. WPKI (Wireless Public Key Infrastructure) is a well known Method to deal with the security issues in wireless LAN. The authentication required by the method becomes a source of unrellability of the hand-off performance. This paper suggests a solution to overcome the instability while using the WPKI technique, Prior to getting into the next region, a station is provided with the keys of the surrounding regions so that the possible delay problem can be avoided during the actual hand-off time. Thereby the hand-off instability can be solved in the WPKI framework.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.5
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• pp.2762-2777
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• 2017

A fuzzy identity based signature (FIBS) scheme allows a signer with identity ${\omega}$ to generate a signature which could be verified under identity ${\omega}^{\prime}$ if and only if ${\omega}$ and ${\omega}^{\prime}$ are within a certain distance of each other as judged by some metric. In this paper, we propose an efficient FIBS scheme from lattice assumption, which can resist quantum-computer attacks. Without using the Bonsai Tree technique, we utilize the lattice basis delegation technique to generate the private key, which has the advantage of keeping the lattice dimension invariant. We also prove that our proposed scheme is existentially unforgeable under an adaptive chosen message and identity attack in the random oracle model. Compared with existing scheme, our proposed scheme is much more efficient, especially in terms of communication overhead. Since our FIBS scheme possesses similar error-tolerance property, it can be well applied in post-quantum communication biometric authentication environments, where biometric identifiers such as fingerprints, voice, iris and gait are used in human identification.