• Journal of Korea Society of Industrial Information Systems
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• v.13 no.1
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• pp.68-75
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• 2008

Because ad hoc network is vulnerable to attacks such as routing disruption and resource consumption, it is in need of routing protocol security. In this paper, we propose an efficient and secure route discovery protocol for ad hoc network using symmetric key cryptography. This protocol has small computation loads at each hop using symmetric key cryptography. In the Route Reply, encryption/decrytion are used to guard against active attackers disguising a hop on the network.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.4
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• pp.3-15
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• 2008

In 2000, Song. et. al. firstly proposed the Searchable Keyword Encryption System that treated a problem to search keywords on encrypted data. Since then, various Searchable Keyword Encryption Systems based on symmetric and asymmetric methods have been proposed. However, the Searchable Keyword Encryption Systems based on public key system has a problem that the index size for searching keywords on encrypted data increases linearly according to the number of keyword. In this paper, we propose the method that reduces the index size of Searchable Keyword Encryption based on public key system using Bloom Filter, apply the proposed method to PEKS(Public key Encryption with Keyword Search) that was proposed by Boneh. et. al., and analyze efficiency for the aspect of storage.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.11
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• pp.2374-2380
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• 2011

Many people is preferred to mVoIP which offers call telephone-quality and convenient UI as well as free of charge. On the other hand, security of mVoIP is becoming an issue as it using Internet network may have danger about wiretapping. Although traditionally encryption algorithm of symmetric key for security of voice data has been used, ECC algorithm of public key type has been preferring for encryption because it is stronger in part the strength of encryption than others. However, the existing way is restricted by lots of operations in poor mobile environment. Thus this paper proposes the efficiency of resource consumption way by reducing cryptographic operations.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.3 no.2
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• pp.64-69
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• 2010

This paper designs the ABC(Advanced Block Cipher) algorithm which is a 64byte block encryption algorithm, improves the performance of encryption process time, and makes an key exchange using EC-DH. The ABC algorithm reduces basic memory occupation rates using the original data position exchange method which is a data swap key without S-Box, IP-Box and etc. Also, it prepares the exposure of symmetric key using the unfixed encryption(decryption) key excepting the fixed encryption(decryption) key. Therefore, the proposed ABC algorithm in this paper is a proper encryption algorithm in lower memory environment and mobile banking.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.10
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• pp.3572-3590
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• 2014

Cellular automata (CA) based cryptosystem has been studied for almost three decades, yet most of previously reported researches focus on the symmetric key encryption schemes. Up to now, few CA based public key encryption scheme has been proposed. To fill the gap, in this paper, we propose a new public key encryption scheme based on layered cellular automata (LCA). Specifically, in the proposed scheme, based on the T-shaped neighborhood structure, we combine four one-dimensional reversible CAs (set as the private key) to form the transition rules of a two-dimension CA, where the two-dimension CA is set as the corresponding public key. Based on the hardness assumption of the Decisional Dependent CA problem in LCA, we formally prove the proposed scheme is indistinguishably secure against the chosen-plaintext attack (IND-CPA). In addition, we also use a numeric example to demonstrate its feasibility. Finally, analysis of key space and time efficiency are also carried out along with RSA-1024, and the simulation results demonstrate that our proposed scheme is more efficient.

• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.2
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• pp.171-179
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• 2011

Feistel and SPN are the two main structures in a block cipher. Feistel is a symmetric structure which has the same structure in encryption and decryption, but SPN is not a symmetric structure. Encrypt round function and decrypt round function in SPN structure have three parts, round key addition and substitution layer with S-box for confusion and permutation layer for defusion. Most SPN structure for example ARIA and AES uses 8 bit S-Box at substitution layer, which is vulnerable to Square attack, Boomerang attack, Impossible differentials cryptanalysis etc. In this paper, we propose a SPN which has a symmetric structure in encryption and decryption. The whole operations of proposed algorithm are composed of the even numbers of N rounds where the first half of them, 1 to N/2 round, applies a right function and the last half of them, (N+1)/2 to N round, employs an inverse function. And a symmetry layer is located in between the right function layer and the inverse function layer. The symmetric layer is composed with a multiple simple bit slice involution S-Boxes. The bit slice involution S-Box symmetric layer increases difficult to attack cipher by Square attack, Boomerang attack, Impossible differentials cryptanalysis etc. The proposed symmetric SPN block cipher with bit slice involution S-Box is believed to construct a safe and efficient cipher in Smart Card and RFID environments where electronic chips are built in.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.1
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• pp.108-113
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• 2008

A proposed system can decrypt each contents block through a double buffer algorithm which can continually buffer contents by dividing a multimedia contents into some blocks and provides more improved method of encryption than existing system by being not capable of decrypting the whole multimedia contents if one key is exposed. Also, using digital signature and public encryption algorithm for mutual authentication between systems, this paper proposes the system which sends and encrypts symmetric keys for contents encryption through SOAP messages.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.6B
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• pp.414-422
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• 2012

In the paper we present optimized implementation method over sensor mote for HUMMINGBIRD2 algorithm, ultra-light symmetric cryptography. For efficient implementation we maximized the register usage and used optimized addressing method to reduce the encryption and decryption time. With the optimized encryption implementation, we can utilize the efficient secure network over resource constrained sensor mote.

• ETRI Journal
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• v.43 no.6
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• pp.1113-1129
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• 2021

Lightweight ciphers are increasingly employed in cryptography because of the high demand for secure data transmission in wireless sensor network, embedded devices, and Internet of Things. The PRESENT algorithm as an ultralightweight block cipher provides better solution for secure hardware cryptography with low power consumption and minimum resource. This study generates the key using key rotation and substitution method, which contains key rotation, key switching, and binary-coded decimal-based key generation used in image encryption. The key rotation and substitution-based PRESENT architecture is proposed to increase security level for data stream and randomness in cipher through providing high resistance to attacks. Lookup table is used to design the key scheduling module, thus reducing the area of architecture. Field-programmable gate array (FPGA) performances are evaluated for the proposed and conventional methods. In Virtex 6 device, the proposed key rotation and substitution PRESENT architecture occupied 72 lookup tables, 65 flip flops, and 35 slices which are comparably less to the existing architecture.

• Journal of Korea Multimedia Society
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• v.24 no.3
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• pp.406-415
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• 2021

The worldwide spread of the Internet and the digital information revolution have resulted in a rapid increase in the use and transmission of multimedia information due to the rapid development of communication technologies. It is important to protect images in order to prevent problems such as piracy and illegal distribution. To solve this problem, I propose a new digital color image encryption algorithm in this paper. I design a new pseudo-random number generator based on 1D five-neighborhood maximum length cellular automata (FN-MLCA) to change the pixel values of the plain image into unpredictable values. And then I use a 3D chaotic cat map to effectively shuffle the positions of the image pixel. In this paper, I propose a method to construct a new MLCA by modeling 1D FN-MLCA. This result is an extension of 1D 3-neighborhood CA and shows that more 1D MLCAs can be synthesized. The safety of the proposed algorithm is verified through various statistical analyses.