• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.31 no.6
• /
• pp.1171-1179
• /
• 2021

Image forensic is performed to check image limpidness. In this paper, a robust scheme is discussed to detect median filtering in low quality images. Detection of median filtering assists in overall image forensic. Improved spatial statistical features are extracted from the image to classify pristine and median filtered images. Image array data is rescaled to enhance the spatial statistical information. Features are extracted using Markov model on enhanced spatial statistics. Multiple difference arrays are considered in different directions for robust feature set. Further, texture operator features are combined to increase the detection accuracy and SVM binary classifier is applied to train the classification model. Experimental results are promising for images of low quality JPEG compression.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.33 no.4
• /
• pp.609-619
• /
• 2023

Recently, crimes using drones, one of the IoT industries have been continuously reported. In particular, drones are characterized by easy access and free movement, so they are used for various crimes such as transporting explosives, transporting drugs, and illegal recording. In order to analyze and investigate these criminal acts, drone forensic research is highly emphasized. Media data, PII, and flight records are digital forensic artifacts that can be acquired from drones, in particluar flight records are important artifacts since they can be used to trace drone activities. Therefore, in this paper, the characteristics of the deleted flight record files of DJI drones are presented and verified using the Phantom3, Phantom4 andMini2 models, two drones with differences in characteristics. Additionally, the recovery level is analyzed using the flight record file characteristics, and lastly, drones with the capacity to recover flight records for each drone model and drone models without it are classified.

• Journal of KIISE:Databases
• /
• v.37 no.6
• /
• pp.292-299
• /
• 2010

Recently, as flash memory is used as digital storage devices, necessity for digital forensics is growing in a flash memory area for digital evidence analysis. For this purpose, it is important to recover crashed files stored on flash memory efficiently. However, it is inefficient to apply the hard disk based file recovery techniques to flash memory, since hard disk and flash memory have different characteristics, especially flash memory being unable to in-place update. In this paper, we propose a flash-aware file recovery technique for digital forensics. First, we propose an efficient search technique to find all crashed files. This uses meta-data maintained by FTL(Flash Translation Layer) which is responsible for write operation in flash memory. Second, we advise an efficient recovery technique to recover a crashed file which uses data location information of the mapping table in FTL. Through diverse experiments, we show that our file recovery technique outperforms the hard disk based technique.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
• /
• 2006.06a
• /
• pp.397-402
• /
• 2006

디지털 범죄 수사 능력은 디지털 포렌식 기술 개발 뿐만 아니라 정책적인 수사체계가 얼마나 잘되어 있느냐에 따라 달라진다. 점차 다양화 되고 지능화 되어가는 디지털 범죄를 수사하기 위해서는 디지털 범죄 수사 체계 모델링이 필요하다. 따라서 본고에서는 디지털 범죄의 종류와 그에 적합한 수사 절차를 언급하고, UML(Unified Modeling Language)을 이용하여 디지털 범죄 수사 절차를 체계화하고 모델링하는 방법을 제시하고자 한다.

• Journal of the Korea Convergence Society
• /
• v.1 no.1
• /
• pp.49-55
• /
• 2010

As the developing of the information communication technology, more and more devices are with the capacity of communication and networking. The convergence businesses which communicate with the devices have been developing rapidly. The IT convergence communication is viewed as one of the next frontiers in wireless communications. In this paper, we analyze detailed security threats against M2M(Machine to Machine), intelligent vehicle, smart grid and u-Healthcare in IT convergence architecture. We proposed a direction of the IT convergence security that imbedded system security, forensic security, user authentication and key management scheme.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.23 no.5
• /
• pp.947-955
• /
• 2013

Most of the enterprise information is stored in the database. Therefore, in order to investigate the company's criminal behavior, forensic analysis is important for the database and delete record is a need to develop recovery techniques. This paper is explained structure of the oracle database tablespace file and analyzed system tables that stored table information. Further, we suggests a method of recovery for deleted record in oracle tablespace.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2017.05a
• /
• pp.425-426
• /
• 2017

Ransomware has caused a lot of damage by attacking disks of government agencies, financial institutions and corporations. This has been exploited for monetary damages and Taking personal information. In this paper, we describe the NTFS. Also describe Petya as the example of Ransomware. We used forensic techniques to analyze post-infection status and describes the method for MBR area recovery.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2018.10a
• /
• pp.272-275
• /
• 2018

금전적 이득을 극대화하기 위해 특정 기업, 기관을 대상으로 하는 공격이 증가하고 있다. 공격에 사용되는 일반적인 악성코드의 특징은 기존 시그니처 탐지 방법으로는 탐지하기 어렵다는 것과 공격자의 C&C 서버와의 통신이 일어난다는 점이다. 기업, 기관을 대상으로 이러한 악성코드를 이용한 공격이 시도된다면 감염된 모든 PC로부터 공통적인 네트워크 접속 기록이 발견될 수 있다. 따라서 본 논문에서는 이러한 특징에 중점을 두고 라이브 포렌식 오픈 소스를 활용하여 엔드포인트의 네트워크 접속 기록을 활용해 공통 행위를 탐지하는 기법을 제시하고자 한다.

• The Journal of the Korea Contents Association
• /
• v.7 no.2
• /
• pp.180-190
• /
• 2007

Recently investigation institutions have found the clue leading to solution of the problem by digital evidence. Digital medium is used extensively in real life. Accordingly, offender is leaving from traces of crime to digital form. But, Korea's digital evidence investigation is low level yet. Definite legislation about digital evidence is not readied in present our country. And professional investigation manpower about digital evidence is insufficient. These problem may have to be supplemented urgently. Systematic, technological supporting is required. Specialize and discussed digital evidence investigation's controversial point and capacity reinforcement way for efficient confrontation in cyber crime who is diversified gradually in text.

• Convergence Security Journal
• /
• v.8 no.2
• /
• pp.111-118
• /
• 2008

Computer forensics have been used for verify a crime when industry secret information or cyber crime occurred. However, these methods are simple analysis which cannot find the problem of deleted files. Therefore these cannot be a trusty evidence in a law court. We studied with focus on connectivity principle because it has never tried yet. In this paper, we developed optimizing detection model through systemized analysis between user-delete method and operating system-delete method. Detection model has 3 cases; Firstly, case of deleted by a user, secondly, case of deleted by application. Thirdly case of deleted by operating system. Detection model guarantees optimized performance because it is used in actual field.