• Title/Summary/Keyword: Brute Force Method

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A Secure and Practical Encrypted Data De-duplication with Proof of Ownership in Cloud Storage (클라우드 스토리지 상에서 안전하고 실용적인 암호데이터 중복제거와 소유권 증명 기술)

  • Park, Cheolhee;Hong, Dowon;Seo, Changho
    • Journal of KIISE
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    • v.43 no.10
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    • pp.1165-1172
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    • 2016
  • In cloud storage environment, deduplication enables efficient use of the storage. Also, in order to save network bandwidth, cloud storage service provider has introduced client-side deduplication. Cloud storage service users want to upload encrypted data to ensure confidentiality. However, common encryption method cannot be combined with deduplication, because each user uses a different private key. Also, client-side deduplication can be vulnerable to security threats because file tag replaces the entire file. Recently, proof of ownership schemes have suggested to remedy the vulnerabilities of client-side deduplication. Nevertheless, client-side deduplication over encrypted data still causes problems in efficiency and security. In this paper, we propose a secure and practical client-side encrypted data deduplication scheme that has resilience to brute force attack and performs proof of ownership over encrypted data.

A study on User Authentication Technology of Numeric based Pattern Password (숫자기반의 패턴 형식 패스워드 사용자인증 기술)

  • Ju, Seung-Hwan;Seo, Hee-Suk
    • Journal of the Korea Society of Computer and Information
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    • v.17 no.9
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    • pp.65-73
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    • 2012
  • The traditional text-based password is vulnerable guessing, dictionary attacks, keyloggers, social engineering, stole view, etc. these vulnerability effect more serious problem in a mobile environment. In this study, By using the pattern number to enter the password of an existing four-digit numeric password, User easily use to new password system. The technology on pattern based numerical password authorization proposed in this paper would intensify the security of password which holds existing 10 numbers of cases by authorizing a user and would not invade convenience of use by providing high security and making users memorize only four numbers like old method. Making users not have inconvenience and raising complexity, it would have a strength to an shoulder surfing attack of an attacker. So I study password system that represents the shape-based of number. I propose the new password system to prevent peeking attacks and Brute-force attack, and this proposal is to review the security and usability.

Study on Data Normalization and Representation for Quantitative Analysis of EEG Signals (뇌파 신호의 정량적 분석을 위한 데이터 정규화 및 표현기법 연구)

  • Hwang, Taehun;Kim, Jin Heon
    • Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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    • v.9 no.6
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    • pp.729-738
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    • 2019
  • Recently, we aim to improve the quality of virtual reality contents based on quantitative analysis results of emotions through combination of emotional recognition field and virtual reality field. Emotions are analyzed based on the participant's vital signs. Much research has been done in terms of signal analysis, but the methodology for quantifying emotions has not been fully discussed. In this paper, we propose a normalization function design and expression method to quantify the emotion between various bio - signals. Use the Brute force algorithm to find the optimal parameters of the normalization function and improve the confidence score of the parameters found using the true and false scores defined in this paper. As a result, it is possible to automate the parameter determination of the bio-signal normalization function depending on the experience, and the emotion can be analyzed quantitatively based on this.

Contributions of Emissions and Atmospheric Physical and Chemical Processes to High PM2.5 Concentrations on Jeju Island During Spring 2018 (2018년 봄철 제주지역 고농도 PM2.5에 대한 배출량 및 물리·화학적 공정 기여도 분석)

  • Baek, Joo-Yeol;Song, Sang-Keun;Han, Seung-Beom;Cho, Seong-Bin
    • Journal of Environmental Science International
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    • v.31 no.7
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    • pp.637-652
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    • 2022
  • In this study, the contributions of emissions (foreign and domestic) and atmospheric physical and chemical processes to PM2.5 concentrations were evaluated during a high PM2.5 episode (March 24-26, 2018) observed on the Jeju Island in the spring of 2018. These analyses were performed using the community multi-scale air quality (CMAQ) modeling system using the brute-force method and integrated process rate (IPR) analysis, respectively. The contributions of domestic emissions from South Korea (41-45%) to PM2.5 on the Jeju Island were lower than those (81-89%) of long-range transport (LRT) from China. The substantial contribution of LRT was also confirmed in conjunction with the air mass trajectory analysis, indicating that the frequency of airflow from China (58-62% of all trajectories) was higher than from other regions (28-32%) (e.g., South Korea). These results imply that compared to domestic emissions, emissions from China have a stronger impact than domestic emissions on the high PM2.5 concentrations in the study area. From the IPR analysis, horizontal transport contributed substantially to PM2.5 concentrations were dominant in most of the areas of the Jeju Island during the high PM2.5 episode, while the aerosol process and vertical transport in the southern areas largely contributed to higher PM2.5 concentrations.

Study on The Data Decryption and Artifacts Analysis of KakaoTalk in Windows Environment (윈도우 환경에서 카카오톡 데이터 복호화 및 아티팩트 분석 연구)

  • Minuook Jo;Nam Su Chang
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.33 no.1
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    • pp.51-61
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    • 2023
  • Messengers such as KakaoTalk, LINE, and Facebook Messenger are universal means of communication used by anyone. As the convenience functions provided to users and their usage time increase, so does the user behavior information remaining in the artifacts, which is being used as important evidence from the perspective of digital forensic investigation. However, for security reasons, most of the data is currently stored encrypted. In addition, cover-up behaviors such as intentional manipulation, concealment, and deletion are increasing, causing the problem of delaying digital forensic analysis time. In this paper, we conducted a study on the data decryption and artifacts analysis in a Windows environment for KakaoTalk, the messenger with the largest number of users in Korea. An efficient way of obtaining a decryption key and a method of identifying and decrypting messages attempted to be deleted are presented, and thumbnail artifacts are analyzed.

Secure Certificates Duplication Method Among Multiple Devices Based on BLE and TCP (BLE 및 TCP 기반 다중 디바이스 간 안전한 인증서 복사 방법)

  • Jo, Sung-Hwan;Han, Gi-Tae
    • KIPS Transactions on Computer and Communication Systems
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    • v.7 no.2
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    • pp.49-58
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    • 2018
  • A certificate is a means to certify users by conducting the identification of the users, the prevention of forgery and alteration, and non-repudiation. Most people use an accredited certificate when they perform a task using online banking, and it is often used for the purpose of proving one's identity in issuing various certificates and making electronic payments in addition to online banking. At this time, the issued certificate exists in a file form on the disk, and it is possible to use the certificate issued in an existing device in a new device only if one copies it from the existing device. However, most certificate duplication methods are a method of duplication, entering an 8-16 digit verification code. This is inconvenient because one should enter the verification code and has a weakness that it is vulnerable to security issues. To solve this weakness, this study proposes a method for enhancing security certificate duplication in a multi-channel using TCP and BLE. The proposed method: 1) shares data can be mutually authenticated, using BLE Advertising data; and 2) encrypts the certificate with a symmetric key algorithm and delivers it after the certification of the device through an ECC-based electronic signature algorithm. As a result of the implementation of the proposed method in a mobile environment, it could defend against sniffing attacks, the area of security vulnerabilities in the existing methods and it was proven that it could increase security strength about $10^{41}$ times in an attempt of decoding through the method of substitution of brute force attack existing method.

Travelling Salesman Problem Based on Area Division and Connection Method (외판원 문제의 지역 분할-연결 기법)

  • Lee, Sang-Un
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.15 no.3
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    • pp.211-218
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    • 2015
  • This paper introduces a 'divide-and-conquer' algorithm to the travelling salesman problem (TSP). Top 10n are selected beforehand from a pool of n(n-1) data which are sorted in the ascending order of each vertex's distance. The proposed algorithm then firstly selects partial paths that are interconnected with the shortest distance $r_1=d\{v_i,v_j\}$ of each vertex $v_i$ and assigns them as individual regions. For $r_2$, it connects all inter-vertex edges within the region and inter-region edges are connected in accordance with the connection rule. Finally for $r_3$, it connects only inter-region edges until one whole Hamiltonian cycle is constructed. When tested on TSP-1(n=26) and TSP-2(n=42) of real cities and on a randomly constructed TSP-3(n=50) of the Euclidean plane, the algorithm has obtained optimal solutions for the first two and an improved one from that of Valenzuela and Jones for the third. In contrast to the brute-force search algorithm which runs in n!, the proposed algorithm runs at most 10n times, with the time complexity of $O(n^2)$.

Vector Approximation Bitmap Indexing Method for High Dimensional Multimedia Database (고차원 멀티미디어 데이터 검색을 위한 벡터 근사 비트맵 색인 방법)

  • Park Joo-Hyoun;Son Dea-On;Nang Jong-Ho;Joo Bok-Gyu
    • The KIPS Transactions:PartD
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    • v.13D no.4 s.107
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    • pp.455-462
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    • 2006
  • Recently, the filtering approach using vector approximation such as VA-file[1] or LPC-file[2] have been proposed to support similarity search in high dimensional data space. This approach filters out many irrelevant vectors by calculating the approximate distance from a query vector using the compact approximations of vectors in database. Accordingly, the total elapsed time for similarity search is reduced because the disk I/O time is eliminated by reading the compact approximations instead of original vectors. However, the search time of the VA-file or LPC-file is not much lessened compared to the brute-force search because it requires a lot of computations for calculating the approximate distance. This paper proposes a new bitmap index structure in order to minimize the calculating time. To improve the calculating speed, a specific value of an object is saved in a bit pattern that shows a spatial position of the feature vector on a data space, and the calculation for a distance between objects is performed by the XOR bit calculation that is much faster than the real vector calculation. According to the experiment, the method that this paper suggests has shortened the total searching time to the extent of about one fourth of the sequential searching time, and to the utmost two times of the existing methods by shortening the great deal of calculating time, although this method has a longer data reading time compared to the existing vector approximation based approach. Consequently, it can be confirmed that we can improve even more the searching performance by shortening the calculating time for filtering of the existing vector approximation methods when the database speed is fast enough.

Contract-based Access Control Method for NFT Use Rights

  • Jeong, Yoonsung;Ko, Deokyoon;Seo, Jungwon;Park, Sooyong;Kim, Seong-Jin;Kim, Bum-Soo;Kim, Do-Young
    • Journal of the Korea Society of Computer and Information
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    • v.27 no.11
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    • pp.1-11
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    • 2022
  • In this paper, we propose an NFT(Non-Fungible Token)-based access control method for safely sharing data between users in blockchain environment. Since all data stored in the blockchain can be accessed by anyone due to the nature of the technology, it is necessary to control access except for authorized users when sharing sensitive data. For that, we generate each data as NFT and controls access to the data through the smart contract. In addition, in order to overcome the limitations of single ownership of the existing NFT, we separated the NFT into ownership and use rights, so that data can be safely shared between users. Ownership is represented as an original NFT, use rights is represented as a copied NFT, and all data generated as NFT is encrypted and uploaded, so data can be shared only through the smart contract with access control. To verify this approach, we set up a hypothetical scenario called Building Information Modeling (BIM) data trade, and deployed a smart contract that satisfies 32 function call scenarios that require access control. Also, we evaluated the stability in consideration of the possibility of decryption through brute-force attack. Through our approach, we confirmed that the data can be safely shared between users in blockchain environment.

PM2.5 Simulations for the Seoul Metropolitan Area: (II) Estimation of Self-Contributions and Emission-to-PM2.5 Conversion Rates for Each Source Category (수도권 초미세먼지 농도모사 : (II) 오염원별, 배출물질별 자체 기여도 및 전환율 산정)

  • Kim, Soontae;Bae, Changhan;Yoo, Chul;Kim, Byeong-Uk;Kim, Hyun Cheol;Moon, Nankyoung
    • Journal of Korean Society for Atmospheric Environment
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    • v.33 no.4
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    • pp.377-392
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    • 2017
  • A set of BFM (Brute Force Method) simulations with the CMAQ (Community Multiscale Air Quality) model were conducted in order to estimate self-contributions and conversion rates of PPM (Primary $PM_{2.5}$), $NO_x$, $SO_2$, $NH_3$, and VOC emissions to $PM_{2.5}$ concentrations over the SMA (Seoul Metropolitan Area). CAPSS (Clean Air Policy Support System) 2013 EI (emissions inventory) from the NIER (National Institute of Environmental Research) was used for the base and sensitivity simulations. SCCs (Source Classification Codes) in the EI were utilized to group the emissions into area, mobile, and point source categories. PPM and $PM_{2.5}$ precursor emissions from each source category were reduced by 50%. In turn, air quality was simulated with CMAQ during January, April, July, and October in 2014 for the BFM runs. In this study, seasonal variations of SMA $PM_{2.5}$ self-sensitivities to PPM, $SO_2$, and $NH_3$ emissions can be observed even when the seasonal emission rates are almost identical. For example, when the mobile PPM emissions from the SMA were 634 TPM (Tons Per Month) and 603 TPM in January and July, self-contributions of the emissions to monthly mean $PM_{2.5}$ were $2.7{\mu}g/m^3$ and $1.3{\mu}g/m^3$ for the months, respectively. Similarly, while $NH_3$ emissions from area sources were 4,169 TPM and 3,951 TPM in January and July, the self-contributions to monthly mean $PM_{2.5}$ for the months were $2.0{\mu}g/m^3$ and $4.4{\mu}g/m^3$, respectively. Meanwhile, emission-to-$PM_{2.5}$ conversion rates of precursors vary among source categories. For instance, the annual mean conversion rates of the SMA mobile, area, and point sources were 19.3, 10.8, and $6.6{\mu}g/m^3/10^6TPY$ for $SO_2$ emissions while those rates for PPM emissions were 268.6, 207.7, and 181.5 (${\mu}g/m^3/10^6TPY$), respectively, over the region. The results demonstrate that SMA $PM_{2.5}$ responses to the same amount of reduction in precursor emissions differ for source categories and in time (e.g. seasons), which is important when the cost-benefit analysis is conducted during air quality improvement planning. On the other hand, annual mean $PM_{2.5}$ sensitivities to the SMA $NO_x$ emissions remains still negative even after a 50% reduction in emission category which implies that more aggressive $NO_x$ reductions are required for the SMA to overcome '$NO_x$ disbenefit' under the base condition.