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    Printer identication based on a printed document has many desirable forensic applications. In the electropho- tographic process (EP) quasiperiodic banding artifacts can be used as an effective intrinsic signature. However, in text only document analysis, the absence of large midtone ar- eas makes it difcult to capture suitable signals for banding detection. Frequency domain analysis based on the pro- jection signals of individual characters does not provide enough resolution for proper printer identication. Ad- vanced pattern recognition techniques and knowledge about the print mechanism can help us to device an appropriate method to detect these signatures. We can get reliable in- trinsic signatures from multiple projections to build a clas- sier to identify the printer. Projections from individual characters can be viewed as a high dimensional data set. In order to create a highly effective pattern recognition tool, this high dimensional projection data has to be repre- sented in a low dimensional space. The dimension reduc- tion can be performed by some well known pattern recog- nition techniques. Then a classier can be built based on the reduced dimension data set. A popular choice is the Gaussian Mixture Model where each printer can be rep- resented by a Gaussian distribution. The distributions of all the printers help us to determine the mixing coefcient for the projection from an unknown printer. Finally, the decision making algorithm can vote for the correct printer. In this paper we will describe different classication algo- rithms to identify an unknown printer. We will present the experiments based on several different EP printers in our printer bank. The classication results based on different classiers will be compared .

    Banding is one of the image artifacts for electrophotographic (EP) printers. Due to its origin within the EP process, it can also be viewed as an intrinsic signature of the specific printer. Modulating the EP process to generate banding signals that are below the human visual threshold but can be detected by effective detection approach can further extend the signature capacity. This deliberate banding signal can be viewed as extrinsic signature of a printer. Since modulating the printing process provides significant barrier of entry, it is effective in limiting the attack possibilities and can be an effective method to embed needed information regarding the document and the device it was printed on to provide unprecedented forensic information. One of the key issues with embedding extrinsic signature is the information should not be detectable by the human observer. However, the signature needs to be detectable by a suitable detection algorithm. In this paper, we will propose one method to modulate the exposure of the EP process to embed controlled quasi-periodic signature into a document. Based on the system level modeling and experimental verification of the EP process, machine detectable signatures that are below the human visual threshold can be embedded into a printed document without any perceivable degradation in image quality. Preliminary experiment results confirm our hypothesis that with properly designed control techniques, effective extrinsic signatures can be embedded into a document.

In today’s digital world securing dierent forms of content is very important in terms of protecting copyright and verifying authenticity. Many techniques have been developed to protect audio, video, digital documents, images, and programs (executable code). One example is watermarking of digital audio and images. We believe that a similar type of protection for printed documents is very important. The goals of our work are to securely print and trace documents on low cost consumer printers such as inkjet and electrophotographic (laser) printers. We will accomplish this through the use of intrinsic and extrinsic features obtained from modelling the printing process. In this paper we describe the use of image texture analysis to identify the printer used to print a document. In particular we will describe a set of features that can be used to provide forensic information about a document. We will demonstrate our methods using 10 EP printers.

In forensic applications, identification of the source of a printed document can be very critical. However, this task is very challenging, because there are a variety of factors, such as the media type, the age of the printer, and the amount of colorant left in the cartridge that can affect the characteristics of a printed document. For inkjet printers, the availability of different print modes, and the use of variety of ink types adds even more complexity to this process. In this paper, we investigate different texture features of the characters printed by inkjet printers for classification based on text-only documents. We check the in model stability of these features by using a cost function. Finally, we perform stepwise discriminant analysis to reduce the feature set.

Printer identification based on a printed document can provide forensic information to protect copyright and verify authenticity. In addition to intrinsic features (intrinsic signatures) of the printer, modulating the printing process to embed specific signature (extrinsic signatures) will further extend the encoding capacity. Some features generated by modulating EP process such like raggedness of the edge in the text, can be designed and utilized to help develop the extrinsic signature. By increasing the level of modulation, which increase reliability of detection and thus capacity, we can drive the extrinsic signature to a point without perceptual degradation of the image quality. In this paper, we will investigate embedding extrinsic signature in text documents using laser intensity as a signal modulation source and develop extrinsic signatures using both frequency as well as amplitude modulation. Preliminary experimental results showed that it is feasible to embed detectable extrinsic signatures in text characters without degrading perceptual text quality.

In today’s digital world securing different forms of content is very important in terms of protecting copyright and verifying authenticity. We have pre- viously described the use of image texture analy- sis to identify the printer used to print a docu- ment. In particular we described a set of features that can be used to provide forensic information describing a document. In this paper we will in- troduce a printer identification process that uses a support vector machine classifier. We will also examine the effect of font size, font type, paper type, and “printer age”.

HE, QINGFENG. Requirements-Based Access Control Analysis and Policy Specification. (Under the direction of Dr. Ana (Annie) I. Antón.)  Access control is a mechanism for achieving confidentiality and integrity in software systems.  Access control policies (ACPs) define how access is managed and the high-level rules of who can access what information under certain conditions. Traditionally, access control policies have been specified in an ad-hoc manner, leaving systems vulnerable to security breaches. ACP specification is often isolated from requirements analysis, resulting in policies that are not in compliance with system requirements. This dissertation introduces the Requirements-based Access Control Analysis and Policy Specification (ReCAPS) method for deriving access control policies from various sources, including software requirements specifications (SRS), software designs, and high-level security/privacy policies. The ReCAPS method is essentially an analysis method supported by a set of heuristics and a software tool: the Security and Privacy Requirements Analysis Tool (SPRAT). The method was developed in two formative case studies and validated in two summative case studies. All four case studies involved operational systems,  and ReCAPS evolved as a result of the lessons learned from applying the method to these case studies. Further validation of the method was performed via an empirical study to evaluate the usefulness and effectiveness of the approach.  Results from these evaluations indicate that the process and heuristics provided by the ReCAPS method are useful for specifying database-level and application-level ACPs. Additionally, ReCAPS integrates policy specification into software development, thus providing a basic framework for ensuring compliance between different levels of policies, system requirements and software design. The method also improves the quality of requirements specifications and system designs by clarifying ambiguities and resolving conflicts across these artifacts.

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  In this paper we describe methods for forensic charac- terization of devices. This is important in verifying the trust and authenticity of data and the device that created it. We will present and examine current forensic identica- tion techniques for RF devices, printers, cameras, and show how these techniques can be generalized for use with other devices.

In this paper we will overview the use of data hiding techniques in digital images. In particular we will describe how one can use Steganography to hide information in a digital image. Steganography is related to cryptography and is the basis for many of the digital watermarking techniques currently being developed. The interest in data hiding has risen with the recent activity in digital copyright protection schemes. One way to protect the ownership of a digital image is to secretly embed data in the content of the image identifying the owner. This paper will review recent developments in data hiding, specifically as it pertains to copyright protection of digital images.

Many image watermarks have been proposed to protect intellectual property in an age where digital images may be easily modified and perfectly reproduced. In a fragile marking system, a signal (watermark) is embedded within an image such that subsequent alterations to the watermarked image can be detected with high probability. The insertion of the watermark is perceptually invisible under normal human observation. These types of marks have found applicability in image authentication systems. In this paper we discuss fragile marking systems and their desirable features, common methods of attack, and survey some recent marking systems.

A digital home network is a cluster of digital audio/visual (A/V) devices including set-top boxes, TVs, VCRs, DVD players, and general-purpose computing devices such as personal computers. The network may receive copyrighted digital multimedia content from a number of sources. This content may be broadcast via satellite or terrestrial systems, transmitted by cable operators, or made available as prepackaged media (e.g., a digital tape or a digital video disc). Before releasing their content for distribution, the content owners may require protection by specifying access conditions. Once the content is delivered to the consumer, it moves across home the network until it reaches its destination where it is stored or displayed. A copy protection system is needed to prevent unauthorized access to bit streams in transmission from one A/V device to another or while it is in storage on magnetic or optical media. Recently, two fundamental groups of technologies, encryption and watermarking, have been identified for protecting copyrighted digital multimedia content. This paper is an overview of the work done for protecting content owners

Digital watermarking research has generally focused upon two classes of watermarks, fragile and robust. Robust watermarks are designed to be detected even after attempts are made to remove them. Fragile watermarks are used for authentication purposes and are capable of detecting even minute changes of the watermarked content. Unfortunately, neither type of watermark is ideal when considering “information preserving” transformations (such as compression) which preserve the meaning or expression of the content and “information altering” transformations (such as feature replacement) which change the expression of the content. In this paper we describe a semi-fragile watermark for still images that can detect information altering transformations even after the watermarked content is subjected to information preserving alterations.

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 (IP), 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.