• Journal of the Korea Institute of Information Security & Cryptology
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• v.19 no.6
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• pp.23-35
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• 2009

Password-Authenticated Key Exchange (PAKE) Protocol is a useful tool for secure communication conducted over open networks without sharing a common secret key or assuming the existence of the public key infrastructure (PKI). It seems difficult to design efficient PAKE protocols using RSA, and thus many PAKE protocols are designed based on the Diffie-Hellman key exchange (DH-PAKE). Therefore it is important to design an efficient PAKE based on RSA function since the function is suitable for designing a PAKE protocol for imbalanced communication environment. In this paper, we propose a computationally-efficient key exchange protocol based on the RSA function that is suitable for low-power devices in imbalanced environment. Our protocol is more efficient than previous RSA-PAKE protocols, required theoretical computation and experiment time in the same environment. Our protocol can provide that it is more 84% efficiency key exchange than secure and the most efficient RSA-PAKE protocol CEPEK. We can improve the performance of our protocol by computing some costly operations in offline step. We prove the security of our protocol under firmly formalized security model in the random oracle model.

• Convergence Security Journal
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• v.12 no.1
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• pp.43-48
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• 2012

In this paper, the requirements for information security are presented in the ubiquitous ecological(u-Eco) city. The various definition of ubiquitous city is analyzed first, the concept of the u-Eco City, services and major projects are then presented. The framework of the integrated operating center for u-Eco city is proposed, the privacy, data security and network facility protection in the center are analyzed. Unlike to previously proposed security algorithms, the light-weight encoding algorithms(such as block/stream encoding, pseudo-random generator, hash function, and public key encoding) in the u-Eco city center are required to communicate the information in the ubiquitous sensor network. Furthermore, the principal policies guaranteeing the secrecy and authentication for the private information are also presented.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.10
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• pp.1125-1130
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• 2014

The quantity and quality of contents containing information are sharply increasing with the rising network speed. In line with this rapid growth of information volume, a new communication protocol using the chaotic signal that can protect contents in communication is proposed as follows. The chaos system has the characteristic of unpredictability due to the sensitive initial values and the similarity of the signals with noise. We configured two chaos systems $F(X_n,Y_n)$ and $G(A_n,B_n)$ that have such characteristics and designed a data communication method using as encryption channel the same chaos signals generated by synchronizing the chaos system G with the F signals. The proposed method was verified with the encryption and decryption of images. The proposed method is different from the existing encrypted communication methods and is expected to lay the foundation for future studies in related areas.is an example of ABSTRACT format.

• The KIPS Transactions:PartC
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• v.16C no.2
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• pp.257-266
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• 2009

Now a days, as increased the use of mobile units like a laptop computer and PDA, the demand for high speed internet service is increasing. On the other hand, PKMv2 which is provided from IEEE 802.16e cannot support fully on the security of high speed internet service. This paper proposes light-weight mutual authentication protocol which solved security problem of PKMv2 related to integrity of mobile node for transmission of safe high speed data of mobile node operating in mobile WiMAX environment. Proposed mutual authentication protocol increases the efficiency as the user in network can move in network safely without additional procedure of authentication between subscriber and base station after user's initial authentication. Also, the proposed mutual authentication protocol is safe from the security attack (the man-in-the-middle attack and reply attack) between subscriber and base station by generating a key adopt to PRF() function using random number and secret value in order to secure certification.

• Journal of Digital Convergence
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• v.13 no.9
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• pp.297-302
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• 2015

The increase in applying IT to vehicles has given birth to smart cars or connected cars. As smarts cars become connected with external network systems, threats to communication security are on the rise. With simulation test results supporting such threats to Convergence security in vehicular communication, concerns are raised over relevant vulnerabilities, while an increasing number of studies on secure vehicular communication are published. Hacking attacks against vehicles are more dangerous than other types of hacking attempts because such attacks may threaten drivers' lives and cause social instability. This paper designed a Convergence security protocol for inter-vehicle and intra-vehicle communication using a hash function, nonce, public keys, time stamps and passwords. The proposed protocol was tested with a formal verification tool, Casper/FDR, and found secure and safe against external attacks.

• Journal of the Korea Society of Computer and Information
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• v.26 no.9
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• pp.89-96
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• 2021

In this paper, we analyzed that the user authentication scheme for TMIS(Telecare Medicine Information System) proposed by Al-Saggaf et al. In 2019, Al-Saggaf et al. proposed authentication scheme using biometric information, Al-Saggaf et al. claimed that their authentication scheme provides high security against various attacks along with very low computational cost. However in this paper after analyzing Al-Saggaf et al's authentication scheme, the Al-Saggaf et al's one are missing random number s from the DB to calculate the identity of the user from the server, and there is a design error in the authentication scheme due to the lack of delivery method. Al-Saggaf et al also claimed that their authentication scheme were safe against a variety of attacks, but were vulnerable to password guessing attack using login request messages and smart cards, session key exposure and insider attack. An attacker could also use a password to decrypt the stored user's biometric information by encrypting the DB with a password. Exposure of biometric information is a very serious breach of the user's privacy, which could allow an attacker to succeed in the user impersonation. Furthermore, Al-Saggaf et al's authentication schemes are vulnerable to identity guessing attack, which, unlike what they claimed, do not provide significant user anonymity in TMIS.