• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.7
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• pp.1060-1070
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• 2022

With the development of information technology, the size of the system has become larger and diversified, and the existing role-based access control has faced limitations. Blockchain technology is being used in various fields by presenting new solutions to existing security vulnerabilities. This paper suggests efficient role-based access control in a blockchain where the required gas and processing time vary depending on the access frequency and capacity of the storage. The proposed method redefines the role of reusable units, introduces a hierarchical structure that can efficiently reflect dynamic states to enhance efficiency and scalability, and includes user-centered authentication functions to enable cryptocurrency linkage. The proposed model was theoretically verified using Markov chain, implemented in Ethereum private network, and compared experiments on representative functions were conducted to verify the time and gas efficiency required for user addition and transaction registration. Based on this in the future, structural expansion and experiments are required in consideration of exception situations.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.23 no.4
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• pp.743-755
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• 2013

In recent years, the malicious apps with malicious code in normal apps are increasingly redistributed in Android market, which may incur various problems such as the leakage of authentication information and transaction information and fraudulent transactions when banking apps to process the financial transactions are exposed to such attacks. Thus the financial authorities established the laws and regulations as an countermeasures against those problems and domestic banks provide the integrity verification functions in their banking apps, yet its reliability has not been verified because the studies of the safety of the corresponding functions have seldom been conducted. Thus this study suggests the vulnerabilities of the integrity verification functions of banking apps by using Android reverse engineering analysis techniques. In case the suggested vulnerabilities are exploited, the integrity verification functions of banking apps are likely to be bypassed, which will facilitate malicious code inserting attacks through repackaging and its risk is very high as proved in a test of this study. Furthermore this study suggests the specific solutions to those vulnerabilities, which will contribute to improving the security level of smartphone financial transaction environment against the application forgery attacks.

• The KIPS Transactions:PartC
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• v.15C no.6
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• pp.573-586
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• 2008

The improved performance and miniaturization of computer and the improvement of wireless communication technology have enabled the emergence of many high quality services. Among them multicast services are receiving much attention and their usage is increasing due to the increase of Internet multimedia services such as video conference, multimedia stream, internet TV, etc. Security plays an important role in mobile multicast services. In this paper, we proposed a secure multicast protocol for a hierarchical micro-mobility environment. The proposed secure multicast protocol provides security services such as authentication, access control, confidentiality and integrity using mechanisms including symmetric/asymmetric key crypto-algorithms and capabilities. To provide forward/backward secrecy and scalability, we used sub-group keys based on the hierarchical micro-mobility environment. With this security services, it is possible to guard against all kinds of security attacks performed by illegal mobile nodes. Attacks executed by internal nodes can be thwarted except those attacks which delete packet or cause network resources to be wasted. We used simulator to measure the performance of proposed protocol. As a result, the simulation showed that effect of these security mechanisms on the multicast protocol was not too high.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.10
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• pp.1912-1918
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• 2016

MPTCP(Multipath Transmission Control Protocol) is able to compose many TCP paths when two hosts connect and the data is able to be transported through these paths simultaneously. When a new path is added, the authentication between both hosts is necessary to check the validity of host. So, MPTCP exchanges a key when initiating an connection and makes a token by using this key for authentication. However the original MPTCP is vulnerable to MITM(Man In The Middle) attacks because the key is transported in clear text. Therefore, we applied a ECDH(Elliptic Curve Diffie-Hellman) key exchange algorithm to original MPTCP and replaced the original key to the ECDH public key. And, by generating the secret key after the public key exchanges, only two hosts is able to make the token using the secret key to add new subflow. Also, we designed and implemented a method supporting encryption and decryption of data using a shared secret key to apply confidentiality to original MPTCP.

• Journal of Digital Convergence
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• v.10 no.2
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• pp.153-159
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• 2012

Now a days, U-healthcare comes into the spotlight as a new business model which combines RFID technology with medical service in the well-being era and IT popularization. U-healthcare service needs a method that can deals with hand-writing, overlap data, forgery and falsification of data, difference between information version that happen in medical process because of graft between RFID technology and u-healthcare. This paper proposes RFID based user certification protocol to protect user's privacy who gets medical service through U-healthcare. In the protocol, secret information of patient does the XOR with the secret key that is created in the hospital to reconsider the stability of security system of U-healthcare and user's data forgery and falsification and privacy and then saves it in the secret key field of patient in DB table. Also, it informs the case of illegal access to certification server and make it approved the access of u-healthcare service by differentiating whether u-healthcare is illegal or not.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.10
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• pp.1786-1795
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• 2006

Portable Internet extended from wireless LAN has a large cell size, similar to a wireless mobile communication. and can provide the seamless service which offers middle-low speed mobility. IEEE 802.16e, the international standard of Portable Internet, uses PKMv2 protocol for authorization and key exchange between a MSS and a BS. This paper proposes a new protocol based on PKMv2, which can provide that MSS is able to do fast authorization with a new BS when soft handover is occurred in a MSS. Our protocol can carry out fast authorization because of reducing the number of messages and parameter exchange, public key encryption and signature in wireless network more than the previous works. It also prevents eavesdropping from an external attacker and keeps the security against impersonation attacks for both a MSS and a BS.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.1
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• pp.81-86
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• 2009

Almost all network systems provide an authentication mechanism based on user ID and password. In such system, it is easy to obtain the user password using a sniffer program with illegal eavesdropping. The one-time password and challenge-response method are useful authentication schemes that protect the user passwords against eavesdropping. In client/server environments, the one-time password scheme using time is especially useful because it solves the synchronization problem. In this paper, we propose a new identification scheme One Pass Identification. The security of Password base System is based on the square root problem, and Password base System is secure against the well known attacks including pre-play attack, off-line dictionary attack and server comprise. A number of pass of Password base System is one, and Password base System processes the password and does not need the key. We think that Password base System is excellent for the consuming time to verify the prover.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.6
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• pp.3865-3871
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• 2014

The U-health service provides medical services with patients anytime or anywhere and is defined as the service that combines information and communication technology with health and medical service. However, it causes some troubles, such as the disclosure of patients' medical information or data spills (personal information extrusion). Moreover, it has the weak point of the security threats associated with data based on existing wire-wireless systems because it conducts data transmission and reception through the network. Therefore, this paper suggests a safe personal information management system by designing integrated certification schema that will help compensate for the weaknesses of the U-health service. In the proposal, the protocols for user information, certification between medical institution and users, data communication encryption & decryption, and user information disuse were designed by applying the ID-Based Encryption, and analyzed such existing systems and PKI Based-based communication process, securely and safely.

• The Journal of the Korea Contents Association
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• v.10 no.3
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• pp.32-43
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• 2010

IPTV is an emerging technology that combines both broadcasting and tele-communication technologies, and provides various multi-media contents to the service subscribers. In general, IPTV broadcasters transmit scrambled signals (multi-media contents) to the paying subscribers, and the users within the acknowledged network descramble the signals using the smart-card. That is, users are verified through communication between STB (Set-Top Box) and smart-card. In 2004, Jiang et al. proposed a secure protocol regarding the verification process. The method has been modified and enhanced by several following research works. However, all the methods that have been proposed so far required modular exponentiation operations which may raise the smart-card costs. In this paper, we propose a new efficient mutual authentication and session-key establishment protocol using only hash functions and exclusive-or operations, and show that the proposed protocol is still secure under various security attacks.

• Journal of KIISE:Information Networking
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• v.31 no.4
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• pp.353-362
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• 2004

Mobile Ad-Hoc network tends to expose scarce computing resources and various security threats because all traffics are carried in air along with no central management authority. To provide secure communication and save communication overhead, a scheme is inevitable to serurely establish session keys. However, most of key establishment methods for Ad-Hoc network focus on the distribution of a group key to all hosts and/or the efficient public key management. In this paper, a secure and efficient scheme is proposed to establish a session key between two Ad-Hoc nodes. The proposed scheme makes use of the secret sharing mechanism and the Diffie-Hellman key exchange method. For secure intra-cluster communication, each member node establishes session keys with its clusterhead, after mutual authentication using the secret shares. For inter-cluster communication, each node establishes session keys with its correspondent node using the public key and Diffie-Hellman key exchange method. The simulation results prove that the proposed scheme is more secure and efficient than that of the Clusterhead Authentication Based Method(1).