Biohashing algorithms map biometric features randomly onto binary strings with user-specific tokenized random
numbers. In order to protect biometric data, these binary strings, the Biohashes, are not allowed to reveal much
information about the original biometric features. In the paper we analyse two Biohashing algorithms using scalar
randomization and random projection respectively. With scalar randomization, multiple bits can be extracted
from a single element in a feature vector. The average information rate of Biohashes is about 0.72. However,
Biohashes expose the statistic information about biometric feature, which can be used to estimate the original
feature. Using random projection method, a feature vector in n dimensional space can be converted into binary
strings with length of m (m ≤ n). Any feature vector can be converted into 2m different Biohashes. The random
projection can roughly preserve Hamming distance between Biohashes. Moreover, the direction information
about the original vector can be retrieved with Biohashes and the corresponding random vectors used in the
projection. Although Biohashing can efficiently randomize biometric features, combining more Biohashes of the
same user can leak essential information about the original feature.
One of the important stages of fingerprint recognition is the registration of the fingerprints with respect to the original template. This is not a straightforward task as fingerprint images may have been subject to rotations and translations. Popular
techniques for fingerprint registration use a reference point to achieve alignment. The drawback of existing methods of
core/reference point detection is their poor performance on rotated images. In this paper, we propose a new approach for
rotation invariant and reliable reference point detection applicable to fingerprints of different quality and types. Our approach
is based on the integration of a directional vector field (representing the doubled ridge orientations in fingerprints)
over a closed contour. We define the reference point as the point of the highest curvature. Areas of high curvature in the fingerprint are characterized by large differences in the orientations and correspond to high curvatures in the directional vector fields. Closed contour integrals of orientation vector field, defined as above, over a circle centered around the reference point corresponds to maximal closed curve integrals, and the values associated with such integrals are rotation invariant. Experimental results prove that with the proposed approach we can locate the reference point with high accuracy. Comparison with existing methods is provided.
KEYWORDS: Biometrics, Data storage, Digital watermarking, Information security, Transponders, Computer security, Iris recognition, Data acquisition, Magnetism, Photography
In this paper we analyze chances and challenges with respect to the security of using biometrics in ID documents. We identify goals for ID documents, set by national and international authorities, and discuss the degree of security, which is obtainable with the inclusion of biometric into documents like passports. Starting from classical techniques for manual authentication of ID card holders, we expand our view towards automatic methods based on biometrics. We do so by reviewing different human biometric attributes by modality, as well as by discussing possible techniques for storing and handling the particular biometric data on the document. Further, we explore possible vulnerabilities of potential biometric passport systems. Based on the findings of that discussion we will expand upon two exemplary approaches for including digital biometric data in the context of ID documents and present potential risks attack scenarios along with technical aspects such as capacity and robustness.
KEYWORDS: Quantization, Digital watermarking, Error analysis, Distortion, Sensors, Modulation, Interference (communication), Signal detection, Information theory, Signal processing
Although quantization index modulation (QIM) schemes are optimal from an information theoretic capacity-maximization point of view, their robustness may be too restricted for widespread practical usage. Most papers assume that host signal samples are identically distributed from a single source distribution and therefore, they do not need to consider local adaptivity. In practice there may be however several reasons for introducing locally varying watermark parameters.
In this paper, we study how the Scalar Costa Scheme (which we take as a representative member of the class of QIM schemes) can be adapted to achieve practical levels of robustness and imperceptibility. We do this by choosing the basic watermark parameters on the basis of a perceptual model. An important aspect is the robustness of the statistic on which the adaptation rule is based. The detector needs to be able to accurately re-estimate the value of the parameters as used by the embedder, even in the presence of strong channel noise. One way to achieve this is to base the adaptation rule on an aggregate of the pixel values in a neighborhood around the relevant pixel. We present an analysis of the robustness-locality trade-off, based on a model for the bit error probability.
In recent years we have seen many initiatives to provide electronic music delivery (EMD) services. We observe that a key success factor in EMD is the transparency of the distribution service. We could compare it with the traditional music distribution via compact discs. By buying a CD, a user acquires a 'free' control of the content, i.e. he can copy it, he can play it multiple times etc. In the electronic equivalent, the usage and digital rights management rules should be transparent, and preferably comparable to the classical method of distributing contents.
It is the goal of this paper to describe a technology concept that facilitates, from a consumer perspective simple EMD service. Digital watermarking and fingerprinting are the two key technologies involved. The watermarking technology is used to convey the information that uniquely identifies a specific transaction, and the fingerprint technology is adopted for key management and security purposes. In this paper, we discuss how these two technologies are integrated in such a way that watermark security (i.e. the inability to maliciously alter the watermark) and distribution efficiency (i.e. the ability to serve multiple consumers with one distribution PC) are maximized.
KEYWORDS: Biometrics, Computer security, Systems modeling, Data modeling, Sensors, Data storage, Error control coding, Binary data, Digital watermarking, Telecommunications
Biometric authentication, i.e. verifying the claimed identity of a person based on physiological characteristics or behavioral traits, has the potential to contribute to both privacy protection and user convenience. From a security point of view, biometric authentication offers the possibility to establish physical presence and unequivocal identification. However from a privacy point of view, the use of biometric authentication also introduces new problems and user concerns. Namely, when used for privacy-sensitive applications, biometric data are a highly valuable asset. When such data are available to unauthorized persons, these data can potentially be used for impersonation purposes, defeating the security aspects that are supposed to be associated with biometric authentication. In this paper, we will systematically unveil critical sections based on the two generic biometric flow models for enrolment and authentication respectively. Based on these critical sections for biometric data in authentication systems, we will point out measures to protect biometric systems. It will be shown that especially techniques using non-reversible representations are needed to disallow malicious use of template information and we will discuss a variant of the Linnartz-Tuyls model for securing biometric templates in detail.
KEYWORDS: Video, Digital watermarking, Video compression, Receivers, Video surveillance, Error analysis, Video processing, Network security, Internet, Sensors
The illegal copying of movies in the cinema is now common practice. Although the quality is fairly low, the economic impact of these illegal copies can be enormous. Philips' digital cinema watermarking scheme is designed for the upcoming digital cinema format and will assist content owners and distributors with tracing the origin of illegal copies. In this paper we consider this watermarking scheme in more detail. A characteristic of this watermarking scheme is that it only exploits the temporal axis to insert a watermark. It is therefore inherently robust to geometrical distortions, a necessity for surviving illegal copying by camcorder recording. Moreover, the scheme resists frame rate conversions resulting from a frame rate mismatch between the camcorder and the projector. The watermarking
scheme has been tested in a 'real' digital cinema environment with good results.
An undesirable side effect of many watermarking and data-hiding schemes is that the host signal into which auxiliary data is embedded is distorted. Finding an optimal balance between the amount of information embedded and the induced distortion is therefore an active field of research. In recent years, with the rediscovery of Costa's seminal paper Writing on Dirty Paper, there has been considerable progress in understanding the fundamental limits of the capacity versus distortion of watermarking and data-hiding schemes. For some applications, however, no distortion resulting from auxiliary data, however small, is allowed. In these cases the use of reversible data-hiding methods provide a way out. A reversible data-hiding scheme is defined as a scheme that allows complete and blind restoration (i.e. without additional signaling) of the original host data. Practical reversible data-hiding schemes have been proposed by Fridrich et al., but little attention has been paid to the theoretical limits. Some first results on the capacity of reversible watermarking schemes have been derived. The reversible schemes considered in most previous papers have a highly fragile nature: in those schemes, changing a single bit in the watermarked data would prohibit recovery of both the original host signal as well as the embedded auxiliary data. It is the purpose of this paper to repair this situation and to provide some first results on the limits of robust reversible data-hiding. Admittedly, the examples provided in this paper are toy examples, but they are indicative of more practical schemes that will be presented in subsequent papers.
KEYWORDS: Digital watermarking, Probability theory, Sensors, Transform theory, Distortion, Information technology, Image sensors, Image filtering, Linear filtering, Telecommunications
One way of recovering watermarks in geometrically distorted images is by performing a geometrical search. In addition to the computational cost required for this method, this paper considers the more important problem of false positives. The maximal number of detections that can be performed in a geometrical search is bounded by the maximum false positive detection probability required by the watermark application. We show that image and key dependency in the watermark detector leads to different false positive detection probabilities for geometrical searches for different images and keys. Furthermore, the image and key dependency of the tested watermark detector increases the random-image-random-key false positive detection probability, compared to the Bernoulli experiment that was used as a model.
KEYWORDS: Video, Digital watermarking, Databases, Video compression, Image segmentation, Visualization, Error control coding, Video coding, Image processing, Data storage
This paper present the concept of robust video hashing as a tool for video identification. We present considerations and a technique for (i) extracting essential perceptual features from a moving image sequences and (ii) for identifying any sufficiently long unknown video segment by efficiently matching the hash value of the short segment with a large database of pre-computed hash values.
KEYWORDS: Digital watermarking, Databases, Error control coding, Information security, Video, Cell phones, Multimedia, Signal processing, Brain, Global system for mobile communications
Robust identification of audio, still images and video is currently almost always associated with watermarking. Although being a powerful tool, there are some relevant issues with the use of watermarking. In this paper we review these issues, and at the same time propose to reconsider the older technique of robust feature recognition as a serious alternative. Moreover, we argue that not only in the context of content recognition, but also for other applications, a benefit is to be expected from the combination of robust feature recognition and digital watermarking.
KEYWORDS: Digital watermarking, Video, Video compression, Receivers, Network security, Information security, Video processing, Computer security, Video surveillance, Internet
Video streaming, or the real-time delivery of video over a data network, is the underlying technology behind many applications including video conferencing, video-on-demand, and the delivery of educational and entertainment content. In many applications, particularly ones involving entertainment content, security issues, such as conditional access and copy protection must be addressed. To resolve these security issues, techniques that include encryption and watermarking need to be developed. Since the video sequences will often be compressed using a scalable compression technique and transported over a lossy packet network using the Internet Protocol, the security techniques must be compatible with the compression method and data transport and be robust to errors. In this paper, we address the issues involved in the watermarking of rate-scalable video streams delivered using a practical network. Watermarking is the embedding of a signal (the watermark) into a video stream that is imperceptible when the stream is viewed but can be detected by a watermark detector. Many watermarking techniques have been proposed for digital images and video, but the issues of streaming have not been fully investigated. A review of streaming video is presented, including scalable video compression and network transport, followed by a brief review of video watermarking and the discussion of watermarking streaming video.
KEYWORDS: Digital watermarking, Digital video discs, Video, Galactic astronomy, Sensors, Analog electronics, Control systems, Curium, Information security, Modulation
Watermarking is an emerging technology that is claimed to have an important application in copyright protection. In this paper we consider the case of video watermarking for DVD-Video copy protection. An overview is given of the system requirements and its implications for the DVD-Video watermarking technology. In particular we focus on the problem of implementing copy generation control. Finally, we report on the status of the standardization discussions taking place in the Copy Protection Technical Working Group. Part of this paper has been presented at the 1999 edition of the ICMCS.
KEYWORDS: Digital watermarking, Video, Video surveillance, Optical filters, Image filtering, Visualization, Interference (communication), Analog electronics, Signal detection, Fourier transforms
This paper presents a video watermarking technology for broadcast monitoring. The technology has been developed at the Philips Research Laboratories in Eindhoven in the context of the European ESPRIT project VIVA (Visual Identity Verification Auditor). The aim of the VIVA project is to investigate and demonstrate a professional broadcast surveillance system. The key technology in the VIVA project is a new video watermarking technique by the name of JAWS (Just Another Watermarking System). The JAWS system has been developed such that the embedded watermarks (1) are invisible, (2) are robust with respect to all common processing steps in the broadcast transmission chain, (3) have a very low probability of false alarms, (4) have a large payload at high rate, and (5) allow for a low complexity and a real-time detection. In this paper we present the basic ingredients of the JAWS technology. We also briefly discuss the performance of JAWS with respect to the requirements of broadcast monitoring.
The standard approach to exploiting motion fields in block-based hybrid video coding schemes is motion compensation of the current frame using the motion field, followed by DCT coding of the residue. In this paper we argue that this separation of approximation methods (non- linear prediction followed by transform coding) is unfortunate in low bit-rate applications. In low bit-rate applications, only a limited set of DCT coefficients is retained. Expressing the end result of motion estimation/compensation followed by separate residue coding in terms of basic linear algebra, we find a sub-optimal linear approximation scheme. In this paper we replace motion compensation and separate residue coding by (optimal) orthogonal projection. We show that for low bit-rate applications, the orthogonal projection method performs better than conventional methods. In one extreme case, it is better to use projection with only 15 DCT coefficients retained, than to use separate residue coding with all 64 DCT coefficients retained. A critical ingredient in the proposed scheme is the choice of an orthogonal basis in the vector spaces involved. In the current scheme, these bases are determined locally, implying a high computational complexity. Possible directions for the reduction of this computational complexity are discussed.
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