• The KIPS Transactions:PartC
• /
• v.18C no.2
• /
• pp.89-96
• /
• 2011

ASR is an excellent program security technique that protects various data memory areas without run-time overhead. ASR hides the addresses of variables from attackers by reordering variables within a data memory area; however, it can be broken by brute force attacks because of a limited data memory space. In this paper, we propose Multiple ASR to overcome the limitation of previous ASR approaches. Multiple ASR separates a data memory area into original and duplicated areas, and compares variables in each memory area to detect an attack. In original and duplicated data memory areas variables are arranged in the opposite order. This makes it impossible to overwrite the same variables in the different data areas in a single attack. Although programs with Multiple ASR show a relatively high run-time overhead due to duplicated execution, programs with many I/O operations such as web servers, a favorite attack target, show 40~50% overhead. In this paper we develop and test a tool that transforms a program into one with Multiple ASR applied.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• v.9 no.2
• /
• pp.545-548
• /
• 2005

Recently, the computing environment of P2P come out to solve the excessive load of the server in the computing environment of the client/server. Currently, operated computing environment of P2P is mainly spreading out P2P system of read name or anonymity base about a publisher, sender and receiver of the file. But, to the current file protection there is three problem. The first problem is to a host become attack target. The second is to received file loose attack of Brute Force. The third is to define target of attack of DOS. To solve the this problem. it divide file into block unit. Each block is safely scattered peers. This paper propose the distribution P2P system of file division. Both proposing system solve the this problem and promote efficiency of file application.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.5 no.11
• /
• pp.2221-2234
• /
• 2011

The fuzzy vault scheme has emerged as a promising solution to user privacy and fingerprint template security problems. Recently, however, the fuzzy vault scheme has been shown to be susceptible to a correlation attack. This paper proposes a novel scheme for one-time templates for fingerprint authentication based on the fuzzy vault scheme. As in one-time passwords, the suggested method changes templates after each completion of authentication, and thus the compromised templates cannot be reused. Furthermore, a huge number of chaff minutiae can be added by expanding the size of the fingerprint image. Therefore, the proposed method can protect a user's fingerprint minutiae against the correlation attack. In our experiments, the proposed approach can improve the security level of a typical approach against brute-force attack by the factor of $10^{34}$.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.18 no.4
• /
• pp.867-875
• /
• 2014

Rapid development of internet service is enabling internet banking services in anywhere and anytime. However, service access through internet can be exposed to adversary easily. To prevent, current service providers execute authentication process with user's identification and password. However, majority of users use short and simple password and do not periodically change their password. As a result of this, user's password could be exposed to attacker's brute force attack. In this paper, we presented enhanced password system which guarantee higher security even though users do not change their current password. The method uses additional secret information to replace real password periodically without replacement of real password.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2015.10a
• /
• pp.643-645
• /
• 2015

SSH 무작위 대입 공격은 전통적인 공격기법이지만 최근까지도 공격이 끊임없이 발생되고 있다. 정상적인 접속을 가장한 은닉 공격(Stealth Attack)이 가능하므로 탐지가 어렵다. 본 논문에서는 방화벽 차단 로그를 분석하여 운영 중인 서버로 향할 수 있는 SSH 무작위 대입 공격 트래픽을 사전에 차단하는 기법을 제안하고, 제안한 기법을 적용한 결과 운영 중인 서버로 공격이 이어지는 것을 평균 46% 이상 예방하는 것을 확인한다.

• ETRI Journal
• /
• v.33 no.6
• /
• pp.935-944
• /
• 2011

As a growing number of individuals are exposed to surveillance cameras, the need to prevent captured videos from being used inappropriately has increased. Privacy-related information can be protected through video encryption during transmission or storage, and several algorithms have been proposed for such purposes. However, the simple way of evaluating the security by counting the number of brute-force trials is not proper for measuring the security of video encryption algorithms, considering that attackers can devise specially crafted attacks for specific purposes by exploiting the characteristics of the target video codec. In this paper, we introduce a new attack for recovering contour information from encrypted H.264 video. The attack can thus be used to extract face outlines for the purpose of personal identification. We analyze the security of previous video encryption schemes against the proposed attack and show that the security of these schemes is lower than expected in terms of privacy protection. To enhance security, an advanced block shuffling method is proposed, an analysis of which shows that it is more secure than the previous method and can be an improvement against the proposed attack.

• Journal of the Korea Society of Computer and Information
• /
• v.22 no.9
• /
• pp.65-71
• /
• 2017

This paper proposes a smart phone authentication method based on user's behavior and habit that is an authentication method against shoulder surfing attack and brute force attack. As smart phones evolve not only storage of personal data but also a key means of financial services, the importance of personal information security in smart phones is growing. When user authentication of smart phone, pattern authentication method is simple to use and memorize, but it is prone to leak and vulnerable to attack. Using the features of the smart phone pattern method of the user, the pressure applied when touching the touch pad with the finger, the size of the area touching the finger, and the time of completing the pattern are used as feature vectors and applied to user authentication security. First, a smart phone user models and stores three parameter values as prototypes for each section of the pattern. Then, when a new authentication request is made, the feature vector of the input pattern is obtained and compared with the stored model to decide whether to approve the access to the smart phone. The experimental results confirm that the proposed technique shows a robust authentication security using subjective data of smart phone user based on habits and behaviors.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.25 no.6
• /
• pp.1319-1326
• /
• 2015

The symmetric key encryption algorithms, such as the AES or the ARIA, generate round keys by the key expansion mechanism. While the algorithm is executed, key expansion mechanism emits information about the secret key by the power consumption. The vulnerability exists that can reduce significantly the candidate of the secret key by the simple power analysis attack using a small number of the power traces. Therefore, we'll have to study about the attack and the countermeasure to prevent information leakage. While a simple power analysis attack on the AES key expansion has been studied since 2002, ARIA is insufficient. This paper presents a simple power analysis attack on 8-bit implementations of the ARIA-128 key expansion. The presented attack efficiently utilizes this information leakage to substantially reduce the key space that needs to be considered in a brute-force search for the secret key. We show that ARIA is vulnerable to a SPA attack based on hamming weight leakage.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.21 no.2
• /
• pp.131-138
• /
• 2011

The previous FPGA cluster systems for a brute force search of DES keyspace have showed cost efficient performance, but the research on optimized implementation of the DES algorithm on a single FPGA has been insufficient. In this paper, the optimized DES implementation for a single FPGA of the commercial FPGA cluster system with 77 Xilinx Virtex5-LX50 FPGAs is proposed. Design space exploration using the number of pipeline stages in a DES core, the number of DES cores and the maximum clock frequency of a DES core is performed which leads to integrating 16 DES cores running at 333MHz. Also low power design is applied to reduce the loss of performance caused by limitation of power supply on each FPGA which results in fitting 8 DES cores running at 333MHz. When the proposed DES implementations would be used in the FPGA cluster system, it is estimated that the DES key would be found at most 2.03 days and 4.06 days respectively.

• Journal of KIISE
• /
• v.42 no.8
• /
• pp.1049-1056
• /
• 2015

Runtime Intrusion Prevention Evaluator (RIPE), published in 2011, is a benchmark suite for evaluating mitigation techniques against 850 attack patterns using only buffer overflow. Since RIPE is built as a single process, defense and attack routines cannot help sharing process states and address space layouts when RIPE is tested. As a result, attack routines can access the memory space for defense routines without restriction. We separate RIPE into two independent processes of defense and attacks so that mitigations based on confidentiality such as address space layout randomization are properly evaluated. In addition, we add an execution mode to test robustness against brute force attacks. Finally, we extend RIPE by adding 38 attack forms to perform format string attacks and virtual table (vtable) hijacking attacks. The revised RIPE contributes to the diversification of attack patterns and precise evaluation of the effectiveness of mitigations.