• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.4
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• pp.941-950
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• 2015

Internet banking is widely used in our life with the development of the internet. At the same time, phishing attacks to internet banking have been increased by using malicious object to make unfair profit. People using internet banking service in Korea is required to install security modules such as anti-virus and keyboard protection. However phishing attack technique has been progressed and the advanced technique such as memory hacking defeats the security module of internet banking service. In this paper, we describe internet banking security modules provided by Korean internet banks and analyze how keyboard encryption module works. And we propose an attack to manipulate account transfer information using javascript. Although keyboard protection module provides two functions that protect leakage and manipulation of account transfer information submitted by users against the malicious program of hackers. Our proposed technique can manipulate the account transfer information and result html pages.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.30 no.4
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• pp.583-592
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• 2020

With the popularization of smartphones, Social Networking Service (SNS) has become the means of communication for modern people. Due to the nature of the means of communication, SNS generates a variety of archive and preservation evidence. Therefore, it is a major analysis target in terms of digital forensic investigation. An application that provides SNS stores data in a central server or database in a smartphone inside for user convenience. Some applications provide encryption for privacy, which can be anti-forensic in terms of digital forensic investigation. Therefore, the study of the encryption method should be continuously preceded. In this paper, we analyzed two applications that provide SQLite-based database encryption through SQLCipher module. Each database was decrypted and key data was identified.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.4
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• pp.860-868
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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. In this paper, we propose a SPN block cipher so called SSB which has a symmetric structure in encryption and decryption. The proposed SSB is composed of the even numbers of N rounds. Each round consists of a round key addition layer, a subsitution layer, a byte exchange layer and a diffusion layer. The subsitution layer of the odd round is inverse function of one of the even round. And the diffusion layer is a MDS involution matrix. The differential and linear attack probability of SSB is $2^{-306}$ which is same with AES. The proposed symmetric SPN block cipher SSB is believed to construct a safe and efficient cipher in Smart Card and RFID environments which is in limited hardware and software resources.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.4
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• pp.778-784
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• 2012

A symmetric block cryptosystem uses an identical cryptographic key at encryption and decryption processes. HIGHT cipher algorithm is 64-bit block cryptographic technology for mobile device that was authorized as international standard by ISO/IEC on 2010. In this paper, block cipher HIGHT algorithm is designed using Verilog-HDL. Four modes of operation for block cipher such as ECB, CBC, OFB and CTR are supported. When continuous message blocks of fixed size are encrypted or decrypted, the desigend HIGHT core can process a 64-bit message block in every 34-clock cycle. The cryptographic processor designed in this paper operates at 144MHz on vertex chip of Xilinx, Inc. and the maximum throughput is 271Mbps. The designed cryptographic processor is applicable to security module of the areas such as PDA, smart card, internet banking and satellite broadcasting.

• Convergence Security Journal
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• v.15 no.4
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• pp.35-41
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• 2015

Internet of Things has a wide range of vulnerabilities are exposed to information security threats. However, this does not deal with the basic solution, the vaccine does not secure encryption for the data transmission. The encryption and authentication message transmitted from one node to the construction of the secure wireless sensor networks is required. In order to satisfy the constraint, and security requirements of the sensor network, lightweight encryption and authentication technologies, the light key management technology for the sensor environment it is required. Mandatory sensor network security technology, privacy protection technology subchannel attack prevention, and technology. In order to establish a secure wireless sensor networks encrypt messages sent between the nodes and it is important to authenticate. Lightweight it shall apply the intrusion detection mechanism functions to securely detect the presence of the node on the network. From the sensor node is not involved will determine the authenticity of the terminal authentication technologies, there is a need for a system. Network security technology in an Internet environment objects is a technique for enhancing the security of communication channel between the devices and the sensor to be the center.

• The Journal of the Korea Contents Association
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• v.5 no.5
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• pp.43-50
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• 2005

POS system that become that is supply net administration and computerization fetters of customer management that become point in istribution network constructed database and use XML-Encryption that is certificate techniques of PKI and standard of security for security that is XML's shortcoming and design distributed processing POS system using XML for data integration by introduction of Ubiquitous concept. This POS system has four advantages. First, Because there is no server, need not to attempt authentication and data transmission every time. Second, can integrate data base by XML and improve portability of program itself. Third, XML data in data transmission because transmit data after encryption data safe .Fourth, After encode whenever process data for data breakup anger of POS system client program and elevation of the processing speed, transmit at because gathering data at data transmission.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.26 no.6
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• pp.1539-1550
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• 2016

In modern society, the number of applications, which needs storage, is increased. Among them, the advance of FinTech increased the importance of storage encryption. FinTech storage, storing sensitive information, should be kept secure. Unless the storage is kept, many users will be damaged monetarily. To prevent this problem, we should encrypt the storage. A EncFS, which is one of the most popular storage encryption application, uses different IVs for each block to provide higher levels of security in the encryption algorithm. However, there is a vulnerability related to the usage of same IVs. In this paper, we propose a technique that decrypts the ciphertexts without knowing the secret key by using the vulnerability. Moreover, we show that the EncFS is not secure under IND-CPA model and propose a new scheme which is secure under IND-CPA model.

• The KIPS Transactions:PartD
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• v.13D no.3 s.106
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• pp.437-444
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• 2006

A chaos cipher system that focuses on the stream cipher system has a demerit that the longer the text is, the slower the speed of the encryption and description and the transmission and reception. On this study, we designed the cipher web mail system showing much better capabilities than the existing web mail system as the text is longer. In the embodiment of the cipher web mail system, we developed the key stream, the encryption and description of the text and the inside and outside mail viewer and so on. After the efficiency test, it was valued high in the respect of the speed of the encryption and description and the transmission and reception. And it made up for the defect of the stream cipher system. We expect that we can use it through the persistent applied study in the server system security, the file security, the security of the internet information, the protection of the e-commerce system information and other fields based on the cipher technique as the wide use cipher system that can replace the block cipher system.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.11 no.1
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• pp.64-72
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• 2001

This paper is on a design of the high-speed cipher IC using IDEA algorithm. The chip is consists of six functional blocks. The principal blocks are encryption and decryption key generator, input data circuit, encryption processor, output data circuit, operation mode controller. In subkey generator, the design goal is rather decrease of its area than increase of its computation speed. On the other hand, the design of encryption processor is focused on rather increase of its computation speed than decrease of its area. Therefore, the pipeline architecture for repeated processing and the modular multiplier for improving computation speed are adopted. Specially, there are used the carry select adder and modified Booth algorithm to increase its computation speed at modular multiplier. To input the data by 8-bit, 16-bit, 32-bit according to the operation mode, it is designed so that buffer shifts by 8-bit, 16-bit, 32-bit. As a result of simulation by 0.25 $\mu\textrm{m}$ process, this IC has achieved the throughput of 1Gbps in addition to its small area, and used 12,000gates in implementing the algorithm.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.21 no.3
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• pp.131-141
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• 2011

OMA(Open Mobile Alliance) is one of the most active group about DRM technology in mobile device field. OMA announced an OMA-DRM v 2.1 standardization in 2007. After then OMA announced OMA-SRM(Secure Removable Media) and SCE(Secure Contents Exchanges) that are the extension of OMA-DRM v2.1. In SCE, a user can form user domain to share contents and rights. So the user can share contents and rights with not only the the OMA-DRM v2.1 but also home devices like mobile phones, personal computers and audios. In this paper, we analyze a sharing technology of OMA-DRM and SCE, and then propose key distribution method using proxy re-encryption and smart card to use shared contents and rights.