Malicious Manipulations Research Articles

A variance-based public verifiable copyright protection scheme surviving intentional attacks

Digital signature and digital timestamp techniques provide well-defined security mechanisms for copyright protection. However, these techniques are not suitable for directly dealing with digital images. For this reason, digital watermarking has received considerable attention for copyright protection. Unfortunately, there are still some challenges in the proposed watermarking schemes. Here cryptographic tools are introduced into watermarking in such a way that the advantages of both cryptographic tools and digital watermarking are available. Publicly verifiable and distortion tolerance properties are therefore possible. In this paper, a variance-based copyright protection method that does not require the original image for copyright logo extraction is proposed. This new method is both lossless and robust. The present scheme is strong enough to resist malicious manipulations including blurring, JPEG compression, noising, sharpening, scaling, cropping, printing-Xeroxing-scanning and unZign and StirMark attacks, while resisting certain intentional attacks, including counterfeiting, collusion/averaging and copy attacks. A series of experiments is conducted to prove the robustness of this method. It is worthwhile to mention that some of these attacks still challenge many watermarking methods. Based on digital signature and digital timestamping, the ownership of the digital image can be publicly verified.

On the security of the digest function in the SARI image authentication system

We investigate the image authentication system SARI, proposed by Lin and Chang (see ibid., vol.11, p.153-68, Feb. 2001), that distinguishes JPEG compression from malicious manipulations. In particular, we took at the image digest component of this system. We show that if multiple images have been authenticated with the same secret key and the digests of these images are known to an attacker, Oscar, then he can cause arbitrary images to be authenticated with this same but unknown key. We show that the number of such images needed by Oscar to launch a successful attack is quite small, making the attack very practical. We then suggest possible solutions to enhance the security of this authentication system.

A robust image authentication method distinguishing JPEG compression from malicious manipulation

Image authentication verifies the originality of an image by detecting malicious manipulations. Its goal is different from that of image watermarking, which embeds into the image a signature surviving most manipulations. Most existing methods for image authentication treat all types of manipulation equally (i.e., as unacceptable). However, some practical applications demand techniques that can distinguish acceptable manipulations (e.g., compression) from malicious ones. In this paper, we present an effective technique for image authentication which can prevent malicious manipulations but allow JPEG lossy compression. The authentication signature is based on the invariance of the relationships between discrete cosine transform (DCT) coefficients at the same position in separate blocks of an image. These relationships are preserved when DCT coefficients are quantized in JPEG compression. Our proposed method can distinguish malicious manipulations from JPEG lossy compression regardless of the compression ratio or the number of compression iterations. We describe adaptive methods with probabilistic guarantee to handle distortions introduced by various acceptable manipulations such as integer rounding, image filtering, image enhancement, or scaling-recaling. We also present theoretical and experimental results to demonstrate the effectiveness of the technique.

Perils of Internet fraud: an empirical investigation of deception and trust with experienced Internet consumers

This study examines consumer evaluations of a real commercial web site and a fraudulent site that imitates it. The forged site contains malicious manipulations designed to increase trust in the site, decrease perceived risk, and ultimately increase the likelihood that visitors would buy from it. Besides measuring the consumer's willingness to buy from the site, this study recorded the actual ordering of a laptop. Results show that most subjects failed to detect the fraud manipulations, albeit a few succeeded. The fraud has the effect of increasing the consumers' reliance in assurance mechanisms and trust mechanisms, which in turn decrease perceived risk and increase trust in the store. The study confirms hypothesized relationships between purchase behavior, willingness to buy, attitudes toward the store, risk, and trust that are consistent with other trust models found in the literature. Overall, the study sheds light on consumers' vulnerability to attack by hackers posing as a legitimate site.

William Thompson: Power in moral economy

Abstract Political theory is broadening its horizons today, looking to the realities of multicultural and marginalised groups who increasingly believe that liberal democratic traditions may be proving inadequate. The liberal political tradition needs revising because of an erroneously assumed homogeneity of human citizens. In falsely universalizing the concept of 'citizen', perhaps liberalism has overlooked important differences of aspiration and priorities of meaning among citizens of states. Ethnic, religious, and sexual sub-groups within societies are increasingly looking for what Amy Gutmann describes as the ‘recognition of every individual's uniqueness and humanity [which] lies at the core ofliberal democracy, understood as a way of political and personal life’. This search for recognition poses a sceptic's challenge to the coherence and applicability of fundamental political concepts such as ‘equalit’, ‘human rights’, ‘citizenship’, ‘power’, and the ‘public good’. This scepticism is about whether and to what extent the current interpretations of these concepts derive from the vested interests and life-meanings of dominant groups within societies. To the extent that these concepts encapsulate the history, the values, and the social assumptions of dominant groups, they may exclude or minimize the differences characteristic of sub-group life-preferences. The valueladen character of these focal concepts, believed to borrow heavily on hierarchies of meaning within dominant groups, need not be intentional or malicious manipulation of concepts for political ends in order to be detrimental to ‘recognition'’or distribution of liberties among marginalized groups.