Showing papers by "Jana Dittmann published in 2013"

Visibility Assessment of Latent Fingerprints on Challenging Substrates in Spectroscopic Scans

Abstract: Our objectives for crime scene forensics are to find the substrates on which finger traces are visible in limited ranges of the electromagnetic spectrum using UV-VIS reflection spectroscopy and to determine the optimal ranges in the interval from 163 to 844 nm. We subjectively assess the visibility of fingerprints within detailed scans with a resolution of 500 ppi and compare the results with those of an automatic visibility assessment based on the streakiness score. Ten different substrates are evaluated, each with three fingerprints from different donors. Streakiness score is confirmed to be a suitable fingerprint visibility indicator on non-structured substrates. We identify two substrates, namely metallic paint and blued metal, on which ridge lines become visible exclusively in UV range from 200 to 400 nm and from 210 to 300 nm correspondingly.

E-Learning of IT Security Threats: A Game Prototype for Children

Abstract: In this paper an e-learning game prototype for primary school children (aged between 7 and 9 years) is introduced. The game teaches children about IT security threats , which they encounter using the Internet. The game is separated into three mini games: virus infection of the computer, inviting somebody in social networks, chatting with strangers. The game design used metaphors and based on standard guidelines of infantile learning environments (e.g. paradigm of simplicity, multidimensional stimuli, characters). Furthermore, the results of a user study of 36 primary school children are presented. In the future, the prototype would be extended by additional metaphors.

Creation of a Public Corpus of Contact-Less Acquired Latent Fingerprints without Privacy Implications

Abstract: Data sets of biometric or forensic samples are an important basis for evaluations and research. Especially biometric data is considered as personal data, which is protected by privacy regulations. Since the data cannot be altered or revoked, at least in some countries, this poses a challenge because rights must be granted to the data’s subject. In particular in Germany and probably in the entire European Union after its reformation of the data protection legislation it is challenging to use such data. Furthermore, with respect to latent fingerprints only very few public data sets exist nowadays. We propose the creation of a public data set without privacy implications consisting of latent fingerprints from artificial fingerprint patterns. On the foundation of a first set of 50 fingerprints on a compact disk surface we report challenges that need to be solved in order to create realistic samples.

First investigation of latent fingerprints long-term aging using chromatic white light sensors

Abstract: Non-invasive high-resolution Chromatic White Light (CWL) measurement devices offer great potential for solving the challenge of latent fingerprints age determination. In this paper, we place 40 prints from different subjects on hard disk platters and capture them from three different indoor locations every week over 1.5 years, acquiring high-resolution time series (10 μm and 20 μm). In contrast to prior findings from Popa et al. (using glass substrates) we show that the ridge thickness of our very precise images does not significantly decrease over time (test goal 1). We furthermore show that pores exhibit a significant loss in contrast and contour, which might lead to the impression of becoming bigger and fewer (test goal 2). Computing the contrast based Binary Pixel aging feature (test goal 3), we observe very characteristic results, leading to the conclusion that the dominant aging property seems to be an overall loss of image contrast rather than a specific change of ridge thickness or pore size. Comparing our findings between three different indoor locations (test goal 4) and discussing them from a police point of view, we conclude that sweat composition, environmental influences and scan parameters have a significant impact on fingerprints long-term aging.

Proceedings of the first ACM workshop on Information hiding and multimedia security

Abstract: It is our great pleasure to welcome you to the 1st ACM Workshop on Information Hiding and Multimedia Security, Montpellier, France, June 17-19, 2013. For over a decade, two workshops have been shaping the landscape of research in multimedia security. On one hand, Information Hiding (aka. IH) was created in 1996 and focused on digital watermarking, steganography and steganalysis, anonymity and privacy, hard to intercept communications and covert/subliminal channels. On the other hand, the ACM Workshop on Multimedia and Security (aka. ACM MMSec) was initiated in 1998 and focused on data hiding, robust/perceptual hash, biometrics, video surveillance, and multimedia forensics. Key seminal works have been published in these two workshops and papers accepted for publication there attracted over 9,000 citations in total. Year after year, the two communities grew closer and the overlap between their respective scope got bigger. As a result, after 14 successful editions each, IH and ACM MMSec decided to merge in a single event in an attempt to establish synergies between the two communities while building on the reputation obtained over the years. The 1st ACM Information Hiding and Multimedia Security Workshop (ACM IHMMSEC) is held at Montpellier, France, June 17-19, 2013. We hope that this first edition of this workshop, resulting from merging two long standing sustainable events, gives birth to an attractive research forum that will facilitate cross-fertilization of ideas among key stakeholders from academia, industry, practitioners and government agencies around the globe. The call for papers attracted 74 submissions from Asia, South America, the United States, Africa, and Europe. The program committee accepted 27 papers (acceptance rate of 36%) that cover a variety of topics, including three invited talks and four special sessions. We hope that these proceedings will serve as a valuable reference for researchers.

Visibility enhancement and validation of segmented latent fingerprints in crime scene forensics

Abstract: Forensic investigators are permanently looking for novel technologies for fast and effective recovering of latent fingerprints at a crime scene. Traditionally, this work is done manually and therefore considered very time consuming. Highly skilled experts apply chemical reagents to improve visibility of traces and use digital cameras or adhesive tape to lift prints. Through an automation of the surface examination, larger areas can be investigated faster. This work amplifies the experimental study on capabilities of a chromatic white-light sensor (CWL) regarding the contact-less lifting of latent fingerprints from differently challenging substrates. The crucial advantage of a CWL sensor compared to taking digital photographs is the simultaneous acquisition of luminance and topography of the surface, extending the standard twodimensional image processing to the analysis of three-dimensional data. The paper focuses on the automatic validation of localized fingerprint regions. In contrast to statistical features from luminance data, previously used for localization, we propose the streakiness of a pattern as the basic feature indicating the fingerprint presence. Regions are analyzed for streakiness using both luminance and topography data. As a result, the human experts significantly save time by dealing with a limited number of approved fingerprints. The experiments show that the validation performance in terms of equal error rate does not exceed 6% even on very challenging substrates regarding high-quality fingerprints.

Statistical Pattern Recognition Based Content Analysis on Encrypted Network: Traffic for the TeamViewer Application

Abstract: In the course of a forensic investigation it might be required to distinguish between different network activities. While various means to analyse network traffic exist, encrypted traffic often makes such an analysis problematic. The focus of this paper is to introduce a method based on statistical pattern recognition on network recordings of encrypted sessions to distinguish between different actions within these sessions. For demonstration purposes the popular remote support and online-meeting application TeamViewer is selected to introduce and discuss an approach to distinguish between file transfers, voice conferences, video conferences, text chat and normal remote sessions within TeamViewer sessions.

Printed fingerprints at crime scenes: a faster detection of malicious traces using scans of confocal microscopes

Abstract: Fingerprint traces are an important part of forensic investigations to identify potential perpetrators. With the possibility of printing traces for quality assurance purposes it is also possible to place malicious traces on crime scenes. In forensics examiners are already aware of multiple identical traces, e.g. produced by stamping fingerprints. The technique of printing fingerprints using artificial sweat allows to create different versions of the same fingerprint, similar to the residue from a finger, which is almost never 100 percent identical to another latent fingerprint. Hence, Kiltz et al.1 introduce a first framework for the detection of such malicious traces in subjective evaluations based on dot patterns of amino acid. Hildebrandt et al.2 introduce a first automated approach for the detection of printed fingerprints using high resolution scans from a chromatic white light sensor. However, the reported recognition accuracy is insufficient for forensic investigations. In this paper we propose an improved feature extraction for scans using a confocal microscope to reduce the overall analysis time and to increase the recognition accuracy. Our evaluation is based on 3000 printed and 3000 real fingerprints on the three surfaces hard disk platter, overhead foil and compact disk advancing the research from Hildebrandt et al.2 Our goal is to benchmark the feature extraction and recognition of printed fingerprints for the three substrates as well as for the combination thereof. The results indicate a significant reduction of the necessary analysis time to less than one minute as well as an improved recognition rate of up to 99.7 percent for all samples on the three surfaces in comparison to the previously achieved 91.48 percent on two surfaces as reported in Hildebrandt et al.2

Statistical latent fingerprint residue recognition in contact-less scans to support fingerprint segmentation

Abstract: The search, acquisition and analysis of latent fingerprints are performed in forensics for over a century. The acquisition methods have evolved during the decades but they are still primarily contact-based and alter the trace. Contactless acquisition systems are subject to ongoing research, allowing for a non-destructive acquisition of latent fingerprints. Those techniques pose opportunities and challenges for forensic investigations. In particular the visibility enhancement of the fingerprint needs to be performed digitally in contrast to the contact-based methods. In this paper we propose and evaluate a pattern recognition based fingerprint residue detection using 16 statistical features, whereas 10 are motivated in [1], [2] and 6 newly introduced, as well as 9 features based on Benford's law [3]. Our goal is to recognize the fingerprint residue as digital visibility enhancement as a foundation for fingerprint segmentation and subsequent biometric comparison of trace evidence from crime scenes. Our evaluation is performed for three different surfaces (white furniture surface, veneered plywood, brushed stainless steel) that are usually found at crime scenes. The test set contains 30 untreated contact-less captured latent fingerprints with additional labeling information as ground truth gathered from differential scans. Our evaluation is split into two parts: in the first evaluation a fingerprint residue recognition accuracy of up to 92.7% is achieved on a cooperative surface. In the second evaluation, based on biometric matching after our residue recognition, we can outperform the matching performance of the ground truth from the differential scans using J48 decision tree classifier on the cooperative white furniture surface, achieving 6 instead of 5 successful matches with an exemplar fingerprint.

Design Aspects of Secure Biometric Systems and Biometrics in the Encrypted Domain

Abstract: This chapter introduces the main security requirements for the biometric processing pipeline and summarizes general design principles and approaches. General IT security principles are reflected and selected paradigms such as template protection by biometric hashing, fuzzy commitment schemes, and fuzzy extractors are reviewed. Further, we discuss the design principles of biometric matching algorithms that operate in the encrypted domain. The overall algorithm design, implementation, and configuration issues are summarized and discussed in an exemplary manner for the case of face biometrics.

Multimedia Systems as Immune System to Improve Automotive Security

Abstract: Our motivation is driven by the fact, that security mechanisms often cause additional efforts and costs, and need to be aligned with safety goals - protecting human and environment. Especially in the field of automotive security, producers are seeking cost efficient, environmental-condition-adaptive (robust) and fast approaches, if possible combined with existing concepts reusing resources. Initially, working in automotive security, it was easy to see that a wide variety of attacks is possible, e.g. using knowledge from classical computer and network security incidents. It became clear, that malicious activities on car IT systems might also lead to safety relevant issues such as accidents with threats to life or physical condition of the driver herself, occupants and people in the environment. We are inspired by the basic law of robotics established by I. Asimov1 and apply it to automotive design: "1. A vehicle may not injure a human being, or, through inaction, allow a human being to come to harm. 2. A vehicle must obey orders given it by human beings except where such orders would conflict with the First Law. 3. A vehicle must protect its own existence as long as such protection does not conflict with the First or Second Law.". This entire bunch of requirements would cause "heavy" technology and expensive solutions. Coming from multimedia security, it became stepwise clearer that we cannot neglect known security mechanisms, but it is worth to combine them with knowledge about multimedia systems (MM systems). For example MM sensory, data streams, protocols, quality etc. enable the car to perceive the occupants and environment more precisely and can help to detect in-car and outside-car anomalies caused by security incidents with an estimation/prediction of harm. Existing automotive components designed for safety, entertainment and comfort services should be able to help in achieving secure and safe car behavior. In the article we discuss the opportunity to understand vehicles as single and cooperative MM systems with the ability to become an enabler for future automobile security detection, warning and reaction strategies - as a kind of vehicular immune system building Multimedia-enabled Asimovian Secure Automobiles (MASA).

Ballistic examinations based on 3D data: a comparative study of probabilistic Hough Transform and geometrical shape determination for circle-detection on cartridge bottoms

Abstract: The application of contact-less optical 3D sensing techniques yielding digital data for the acquisition of toolmarks on forensic ballistic specimens found at crime scenes, as well as the development of computer-aided, semi-automated firearm identification systems that are using 3D information, are currently emerging fields of research with rising importance. Traditionally, the examination of forensic ballistic specimen is done manually by highly skilled forensic experts using comparison microscopes. A partly automation of the comparison task promises examination results that are less dependent on subjective expertise and furthermore a reduction of the manual work needed. While there are some partly automated systems available they are all of proprietary nature to our current knowledge. One necessary requirement for the examination of forensic ballistic specimens is a reliable circle-detection and segmentation of cartridge bottoms. This information is later used for example for alignment and registration tasks, determination of regions of interest, and locally restricted application of complex feature-extraction algorithms. In this work we are using a Keyence VK-X 105 laser-scanning confocal microscope to acquire a very high detail topography image, a laserintensity image, and a color image of the assessed cartridge bottoms simultaneously. The work is focused on a comparison of Hough Transform (21HT) and Geometric Shape Determination for circle-detection on cartridge bottoms using 3D as well as 2D information. We compare the pre-processing complexity, the required processing time, and the ability for a reliable detection of all desired circles. We assume that the utilization of Geometric Shape Detection can reduce the required processing time due to a less complex processing. For application of shape determination as well as for Hough Transform we expect a more reliable circle-detection when using additional 3D information. Our first experimental evaluation, using 100 9mm center fire cartridges shot from 3 different firearms shows positive tendency to verify these suppositions.

Separation of contactless captured high-resolution overlapped latent fingerprints: Parameter optimisation and evaluation

Abstract: Although overlapped latent fingerprints often occur in crime scenes, they usually can not directly be used as forensic evidence as it is difficult for the state-of-the-art fingerprint matchers to separate and match them. There exist separation techniques based on chemical imaging, but they require invasive fingerprint acquisition (e.g. applying chemicals) methods which not only compromise the integrity of potential evidence but also eliminate the possibility of analysing the fingerprints using other means (e.g. spectroscopy). Addressing this issue, in this work we use scanned samples of two overlapped latent fingerprints acquired noninvasively by a Chromatic White Light (CWL) sensor. To properly apply our previous separation approach adapted from Chen et al. on those samples, in this paper we conduct a thorough parameter optimisation. A test set of 20 authentic overlapped fingerprints is used. With a cross examination with 4 templates of 2 different kinds using NIST Biometric Image Software (NBIS), we obtain 160 samples from the matching test, which shows a clear increasing number of positive matching after the separation of the fingerprints and leads to an overall Equal Error Rate (EER) of 8.3%, which is lower than the results from Chen et al. where simulated samples are used.

Digitized forensics: retaining a link between physical and digital crime scene traces using QR-codes

Abstract: The digitization of physical traces from crime scenes in forensic investigations in effect creates a digital chain-of-custody and entrains the challenge of creating a link between the two or more representations of the same trace. In order to be forensically sound, especially the two security aspects of integrity and authenticity need to be maintained at all times. Especially the adherence to the authenticity using technical means proves to be a challenge at the boundary between the physical object and its digital representations. In this article we propose a new method of linking physical objects with its digital counterparts using two-dimensional bar codes and additional meta-data accompanying the acquired data for integration in the conventional documentation of collection of items of evidence (bagging and tagging process). Using the exemplary chosen QR-code as particular implementation of a bar code and a model of the forensic process, we also supply a means to integrate our suggested approach into forensically sound proceedings as described by Holder et al.1 We use the example of the digital dactyloscopy as a forensic discipline, where currently progress is being made by digitizing some of the processing steps. We show an exemplary demonstrator of the suggested approach using a smartphone as a mobile device for the verification of the physical trace to extend the chain-of-custody from the physical to the digital domain. Our evaluation of the demonstrator is performed towards the readability and the verification of its contents. We can read the bar code despite its limited size of 42 x 42 mm and rather large amount of embedded data using various devices. Furthermore, the QR-code's error correction features help to recover contents of damaged codes. Subsequently, our appended digital signature allows for detecting malicious manipulations of the embedded data.

Printing artificial sweat using ink jet printers for the test set generation in forensics: an image quality assessment of the reproducibility of the printing results

Abstract: In order to use scientific expert evidence in court hearings, several criteria must be met. In the US jurisdiction the Daubert decision2 has defined several criteria that might be assessed if a testimony is challenged. In particular the potential for testing or actual testing, as well as known or potential error rate are two very important criteria. In order to be able to compare the results with each other, the reproducible creation of evaluation samples is necessary. However, each latent fingerprint is unique due to external inuence factors such as sweat composition or pressure during the application of a trace. Hence, Schwarz1 introduces a method to print latent fingerprints using ink jet printers equipped with artificial sweat. In this paper we assess the image quality in terms of reproducibility and clarity of the printed artificial sweat patterns. For that, we determine the intra class variance from one printer on the same and on different substrates based on a subjective assessment, as well as the inter class variance between different printers of the same model using pattern recognition techniques. Our results indicate that the intra class variance is primarily inuenced by the drying behavior of the amino acid. The inter class is surprisingly large between identical models of one printer. Our evaluation is performed using 100 samples on an overhead foil and 50 samples on a compact disk surface with 5 different patterns (two line structures, a fingerprint image and two di_erent arrows with a larger area with amino acid) acquired with a Keyence VK-X110 laser scanning confocal microscope.11 The results show a significant difference between the two identical printers allowing for differentiating between them with an accuracy of up to 99%.

High quality training materials to detect printed fingerprints: Benchmarking three different aquisition sensors producing printing templates

Abstract: Schwarz's technique for printing amino acid solutions introduces the possibility of printing large quantities of latent fingerprints for crime scene investigation quality assurance. Nevertheless his technique also unintentionally creates the possibility of leaving printed fingerprints at crime scenes. To help identify those false fingerprints, in our paper we extend the printing pipeline, for training investigators and detection methods. Furthermore, we propose subjective and objective evaluation approaches and first tendencies for boundary ranges for objective evaluation metrics. In particular we use digitized real latent fingerprints as printing source (= template) and different contactless sensors (two different chromatic white light sensors, FRT CWL 600, FRT CWL 1mm, and a confocal microscope Keyence VK-X105) for their acquisition. For the examination of the printed fingerprints one subjective and two objective evaluation approaches are introduced as well as a first tendency for boundary ranges of the objective approach. A Canon PIXMA IP 4600 is used for printing and the Keyence VK-X105 acquires the untreated printed fingerprints. Our benchmarking results show that the acquisition sensor Keyence VK-X105 leads to the highest quality of printed fingerprints. In respect to the boundary ranges our suggested first tendency is: correlation value with 20x-objective: Best = [0,...,0.1150], Average = [0.1151,...,0.1258], Worst = [0.1259,...,1]. With 50x-objective: Best = [0,...,0.1299], Average = [0.1300,..., 0.1443], Worst = [0.1444,...,1]. And for the average value with 20x-objective: Best = [0,...,0.0171], Average = [0.0172,...,0.0260], Worst = [0.0261,...,1]. And with 50x-objective: Best = [0,...,0.0299], Average = [0.0300,...,0.0470], Worst = [0.0471,...,1].

Proposal of a privacy-enhancing fingerprint capture for a decentralized police database system from a legal perspective using the example of Germany and the EU

Abstract: Innovations in biometric and forensic technology promise new use cases for the fight against crime and threats to public security. For example, the police will be able to use a new scanner to capture fingerprint traces from luggage at the airport to detect dangerous manipulations and identify known criminals. Despite these potentially great benefits, such systems also entail risks for society. One aspect of such systems is the biometric and forensic database used to compare fingerprints captured with a wanted list. This paper explores a possible decentralized database system as a solution to risks entailed by central systems. It uses the German and EU law as an example to justify technology design decisions on the basis of the legal requirements.

Erster Konzeptansatz von Sicherheitstypen: Sicherheitsbewusstsein von Kindern und Jugendlichen im Umgang mit dem Internet.

Abstract: Bereits jüngere Kinder im Grundschulalter verwenden heute Computer, Tablet-PCs und Smartphones bzw. das Internet. Laut aktuellen Studien ist dabei das Sicherheitsbewusstsein von Kindern weniger gut ausgeprägt. So sind Kinder aufgrund ihrer Aktivitäten im Internet teilweise zahlreichen Bedrohungen im Internet ausgesetzt. Beispielsweise gehen viele Kinder sehr nachlässig mit ihren persönlichen Daten um. Diese könnten aber von Fremden und Kriminellen missbraucht werden. In diesem Artikel wird der Konzeptansatz der ” Sicherheitstypen“ basierend auf dem theoretischen Konstrukt der ” Sicherheitsmentalitäten“ bezüglich Kriminaliätsrisiken von D. Klimke für das Sicherheitsbewusstsein (IT-Security) von Kindern und Jugendlichen adaptiert. Der in diesem Artikel beschriebene Konzeptansatz stützt sich dabei auf eine umfangreiche Nutzerstudie (Fragebogenbefragung) von 157 Schülern/innen im Alter zwischen 10-15 Jahren eines Gymnasiums. Basierend auf dem Konzeptansatz sollen zukünftig Sensibilisierungsmaßnahmen (z.B. Sicherheitswarnmeldungen) zugeschnitten auf den jeweiligen Sicherheitstyp realisiert werden. 1 Einführung und Motivation Heutzutage benutzen bereits Kinder im Grundschulalter (ab 6 Jahren) Computer, TabletPCs und Smartphones bzw. das Internet. Diese Technologien bieten Kindern und Jugendlichen einerseits Chancen ihren Horizont zu erweitern. So wird ihnen beispielsweise durch die Nutzung sozialer Netzwerke (SN) ermöglicht, Kontakt zu Bekannten zu halten bzw. neue Menschen kennenzulernen. Andererseits sind aber auch Risiken durch die Benutzung der Informationstechnologie (IT) und Internetaktivitäten der Kinder zu bedenken. Laut [Liv11] haben beispielsweise ca. ein Drittel aller Kinder zwischen 9 und 16 Jahren, die ein Profil bei einem Sozialen Netzwerk haben, diese teils sehr persönlichen Profilinformationen (z.B. Familienname, Adresse, Telefonnummer) veröffentlicht. Nur weniger als die Hälfte setzt das SN-Profil auf privat, so dass nur als Freunde betitelte Personen des Profils dieses einsehen können. Dabei gibt es signifikante Unterschiede je nach Geschlecht, Alter und sozio-ökomomischem Status. So halten laut [Liv11] vor allem Mädchen und In diesem Artikel werden der Einfachheit halber Kinder und Jugendliche allgemein als Kinder bezeichnet.