Introduction to BiometricsOutlineReferencesSolutions to Attacks on Biometrics SystemsDigital Watermarking/Information HidingSlide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Challenge/ResponseSlide 15Slide 16Slide 17Cancelable BiometricsSlide 19Slide 20Slide 21Slide 22Multi-BiometricsSlide 24Smartcards, PKI and BiometricsSlide 26Slide 27Slide 28Introduction to BiometricsDr. Bhavani ThuraisinghamThe University of Texas at DallasLecture #25Securing Biometrics Systems - IINovember 21, 2005OutlineSolutions to Attacks on Biometrics SystemsSmart Cards. PKI and BiometricsReferenceshttp://www.research.ibm.com/journal/sj/403/ratha.htmlhttp://www.citer.wvu.edu/members/publications/files/RossMultibiometric_CACM04.pdfhttp://www.smartcardalliance.org/about_alliance/Smart_Card_Biometric_report.cfmhttp://www.bioscrypt.com/assets/security_soutar.pdfDigital watermarking based secure multimodal biometric system: Vatsa, M.; et al, Systems, Man and Cybernetics, 2004 IEEE International Conference Volume 3, pp 2983 -87PalmHashing: a novel approach for cancelable biometrics; ceInformation Processing Letters Volume 93 , #1, 2005 Tee Connie et al. http://www.acm.org/~hlb/publications/dig_wtr/dig_watr.htmlSolutions to Attacks on Biometrics SystemsInformation Hiding / Digital WatermarkingImage-based Challenge Response MethodCancelable BiometricsMulti-BiometricsDigital Watermarking/Information HidingA digital watermark is a digital signal or pattern inserted into a digital image. Since this signal or pattern is present in each unaltered copy of the original image, the digital watermark may also serve as a digital signature for the copies. A given watermark may be unique to each copy (e.g., to identify the intended recipient), or be common to multiple copies (e.g., to identify the document source). In either case, the watermarking of the document involves the transformation of the original into another form. This distinguishes digital watermarking from digital fingerprinting where the original file remains intact, but another file is created that "describes" the original file's content.Digital Watermarking/Information HidingAs a simple example, the checksum field for a disk sector would be a fingerprint of the preceding block of data.Similarly, hash algorithms produce fingerprint files.Digital watermarking is also to be contrasted with public-key encryption, which also transform original files into another form. It is a common practice nowadays to encrypt digital documents so that they become un-viewable without the decryption key. Unlike encryption, however, digital watermarking leaves the original image or (or file) basically intact and recognizable. In addition, digital watermarks, as signatures, may not be validated without special software. Further, decrypted documents are free of any residual effects of encryption, whereas digital watermarks are designed to be persistent in viewing, printing, or subsequent re-transmission or dissemination.Digital Watermarking/Information HidingTwo types of digital watermarks may be distinguished, depending upon whether the watermark appears visible or invisible to the casual viewer. Visible watermarks are used in much the same way as their bond paper ancestors, where the opacity of paper is altered by physically stamping it with an identifying pattern.This is done to mark the paper manufacturer or paper type.One might view digitally watermarked documents and images as digitally "stamped".Invisible watermarks, on the other hand, are potentially useful as a means of identifying the source, author, creator, owner, distributor or authorized consumer of a document or image.For this purpose, the objective is to permanently and unalterably mark the image so that the credit or assignment is beyond dispute.Digital Watermarking/Information HidingIn the event of illicit usage, the watermark would facilitate the claim of ownership, the receipt of copyright revenues, or the success of prosecution.Watermarking has also been proposed to trace images in the event of their illicit redistribution. Whereas past infringement with copyrighted documents was often limited by the unfeasibility of large-scale photocopying and distribution, modern digital networks make large-scale dissemination simple and inexpensive. Digital watermarking makes it possible to uniquely mark each image for every buyer. If that buyer then makes an illicit copy, the illicit duplication may be convincingly demonstrated.In both Web-based and other on-line transaction processing systems, it is undesirable to send uncompressed fingerprint images to the server due to bandwidth limitations. A typical fingerprint image is of the order of 512 × 512 pixels with 256 gray levels, resulting in a file size of 256 Kbytes. This would take nearly 40 seconds to transmit at 53 Kbaud.Unfortunately, many standard compression methods, such as JPEG (Joint Photographic Experts Group), have a tendency to distort the high-frequency spatial and structural ridge features of a fingerprint image. This has led to several research proposals regarding domain-specific compression methods. As a result, an open Wavelet Scalar Quantization (WSQ) image compression scheme proposed by the FBI has become the de facto standard in the industry, because of its low image distortion even at high-compression ratiosDigital Watermarking/Information HidingTypically, the compressed image is transmitted over a standard encrypted channel as a replacement for (or in addition to) the user's PIN. Yet, because of the open compression standard, transmitting a WSQ compressed image over the Internet is not particularly secure.If a compressed fingerprint image bitstream can be freely intercepted (and decrypted), it can be decompressed using readily available software. This potentially allows the signal to be saved and fraudulently reused Digital Watermarking/Information HidingOne way to enhance security is to use data-hiding techniques to embed additional information directly in compressed fingerprint images. For instance, if the embedding algorithm remains unknown, the service provider can look for the appropriate standard watermark to check that a submitted image was indeed generated by a trusted machine (or sensor). Several techniques have been proposed in the literature for hiding digital watermarksMost of
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