Search results for " forensics"
showing 10 items of 30 documents
State of the art in passive digital image forgery detection: copy-move image forgery
2017
Authenticating digital images is increasingly becoming important because digital images carry important information and due to their use in different areas such as courts of law as essential pieces of evidence. Nowadays, authenticating digital images is difficult because manipulating them has become easy as a result of powerful image processing software and human knowledge. The importance and relevance of digital image forensics has attracted various researchers to establish different techniques for detection in image forensics. The core category of image forensics is passive image forgery detection. One of the most important passive forgeries that affect the originality of the image is cop…
Copy-move Forgery Detection via Texture Description
2010
Copy-move forgery is one of the most common type of tampering in digital images. Copy-moves are parts of the image that are copied and pasted onto another part of the same image. Detection methods in general use block-matching methods, which first divide the image into overlapping blocks and then extract features from each block, assuming similar blocks will yield similar features. In this paper we present a block-based approach which exploits texture as feature to be extracted from blocks. Our goal is to study if texture is well suited for the specific application, and to compare performance of several texture descriptors. Tests have been made on both uncompressed and JPEG compressed image…
A roadmap towards improving managed security services from a privacy perspective
2014
Published version of an article in the journal: Ethics and Information Technology. Also available from the publisher at: http://dx.doi.org/10.1007/s10676-014-9348-3 This paper proposes a roadmap for how privacy leakages from outsourced managed security services using intrusion detection systems can be controlled. The paper first analyses the risk of leaking private or confidential information from signature-based intrusion detection systems. It then discusses how the situation can be improved by developing adequate privacy enforcement methods and privacy leakage metrics in order to control and reduce the leakage of private and confidential information over time. Such metrics should allow fo…
Automatic Timeline Construction and Analysis For Computer Forensics Purposes
2014
International audience; To determine the circumstances of an incident, investigators need to reconstruct events that occurred in the past. The large amount of data spread across the crime scene makes this task very tedious and complex. In particular, the analysis of the reconstructed timeline, due to the huge quantity of events that occurred on a digital system, is almost impossible and leads to cognitive overload. Therefore, it becomes more and more necessary to develop automatic tools to help or even replace investigators in some parts of the investigation. This paper introduces a multi-layered architecture designed to assist the investigative team in the extraction of information left in…
An Ontology-Based Approach for the Reconstruction and Analysis of Digital Incidents Timelines
2015
International audience; Due to the democratisation of new technologies, computer forensics investigators have to deal with volumes of data which are becoming increasingly large and heterogeneous. Indeed, in a single machine, hundred of events occur per minute, produced and logged by the operating system and various software. Therefore, the identification of evidence, and more generally, the reconstruction of past events is a tedious and time-consuming task for the investigators. Our work aims at reconstructing and analysing automatically the events related to a digital incident, while respecting legal requirements. To tackle those three main problems (volume, heterogeneity and legal require…
Detection of Duplicated Regions in Tampered Digital Images by Bit-Plane Analysis
2009
In this paper we present a new method for searching duplicated areas in a digital image. The goal is to detect if an image has been tampered by a copy-move process. Our method works within a convenient domain. The image to be analyzed is decomposed in its bit-plane representation. Then, for each bitplane, block of bits are encoded with an ASCII code, and a sequence of strings is analyzed rather than the original bit-plane. The sequence is lexicographically sorted and similar groups of bits are extracted as candidate areas, and passed to the following plane to be processed. Output of the last planes indicates if, and where, the image has been altered.
Hypervisor-assisted Atomic Memory Acquisition in Modern Systems
2019
Reliable memory acquisition is essential to forensic analysis of a cyber-crime. Various methods of memory acquisition have been proposed, ranging from tools based on a dedicated hardware to software only solutions. Recently, a hypervisor-based method for memory acquisition was proposed (Qi et al., 2017; Martignoni et al., 2010). This method obtains a reliable (atomic) memory image of a running system. The method achieves this by making all memory pages non-writable until they are copied to the memory image, thus preventing uncontrolled modification of these pages. Unfortunately, the proposed method has two deficiencies: (1) the method does not support multiprocessing and (2) the method does…
A new resonant Laser-SNMS system for environmental ultra-trace analysis: Installation and optimization
2017
Abstract Localization, analysis and mobility of radioactive contaminated particles is of major concern for assessment of contamination threads and nuclear forensics. For this purpose, a new resonant Laser-SNMS system was developed and set up at the Institute for Radioecology and Radiation Protection for spatially resolved ultra-trace analysis of low concentrated radionuclides directly on environmental samples. This paper describes the adaption and combination of a dedicated Ti:sapphire laser system with a commercial TOF-SIMS instrument for resonant Laser-SNMS. The project includes computer simulations for optimization of the TOF analyzer. Results on synthetic uranium and technetium samples …
Tekniikoita digitaalisten valokuvien aitouden arvioimiseen
2009
Ollari, Ilkka Tietojärjestelmätieteen kandidaatintutkielma / Ilkka Ollari Jyväskylä: Jyväskylän yliopisto, 2009, 28 s. Kandidaatintutkielma Digitaalisten valokuvien muokkaamisesta on tullut hyvin helppoa ja yleistä, mikä on osaltaan johtanut valokuvien luotettavuuden heikentymiseen. Tässä tutkielmassa käsittelen kirjallisuuskatsauksen pohjalta erilaisia valokuvien aitouden arvioimiseen tarkoitettuja tekniikoita. Tutkin mm. sitä, kuinka luotettavasti kyseisillä tekniikoilla valokuvien aitous voidaan varmistaa, ja minkälaisia rajoitteita eri tekniikoilla on. Tekniikat voidaan jakaa aktiivisiin ja passiivisiin. Ensin mainitusta ryhmästä käsittelen vesileimoja, jotka ovat merkittävin aktiivist…
Digitaalisten kuvaväärennösten tunnistaminen JPEG-pakkausta hyödyntäen
2010
Digitaalisten valokuvien muokkaamisesta on tullut hyvin helppoa ja yleistä, mikä on nostanut esille huolen valokuvien uskottavuudesta. Ongelman ratkaisuksi on esitetty erilaisia tekniikoita, joilla valokuvien aitoutta voidaan arvioida. Tarkastelen tässä tutkielmassa niin sanottuja passiivisia tekniikoita, jotka eivät edellytä kuvasta minkäänlaista ennakkotietoa, kuten vesileimaa. Vertailen viittä tällaista tekniikkaa laatimani neljä kohtaa käsittävän kriteeristön pohjalta. Vertailtavia ominaisuuksia ovat tarkkuus, tunnistetut muokkaustyypit, rajoitukset sekä vakaus vastatoimia vastaan. Vertailu osoittaa, että eräs merkittävimmistä tekniikoiden ongelmista on niiden huono toleranssi kuvan häv…