(In)Security of an Efficient Fingerprinting Scheme with Symmetric and Commutative Encryption of IWDW 2005

We analyze the security of a fingerprinting scheme proposed at IWDW 2005. We show two results, namely that this scheme (1) does riot provide seller security: a dishonest buyer can repudiate the fact that, he redistributed a content, and (2) does riot, provide buyer security: a buyer can be framed by a malicious seller

Quaternion-based Encryption/Decryption of Audio Signal Using Digital Image as Variable Key

With the rapid growth of communication technology, cryptography plays a significant role in securing and verification of information exchanged via public communication channels.   The current paper introduces a novel method for encrypting/decrypting audio signal using a selected digital image as a complicated key and cover for audio signal.  Each sample of the audio signal is combined with the values of the three color components of a pixel fetched from the cover image yielding a quaternion number.   The absolute value of this quaternion number is then transmitted and when received, the original value of the audio sample can be extracted using simple quaternion mathematics. A second level of complexity can be added to this approach by applying one of the well-known cryptographic techniques (symmetric or asymmetric).   The suggested approach is implemented using Matlab simulation software and the generated audio signal is compared with the original one using some performance metrics.  The obtained results show that the proposed approach is robust and more secure against cryptanalysis attacks

Analysis of a buyer-seller watermarking protocol for trustworthy purchasing of digital contents

In ubiquitous environments where human users get to access diverse kinds of (often multimedia enabled) services irrespective of where they are, the issue of security is a major concern. Security in this setting encompasses both in the interest of the human users as well as their information and objects that they own. A typical kind of transaction interaction among users and/or machines in these environments is that of exchanging digital objects via purchases and/or ownership transfers, e.g. someone buying a song from iTunes via his iPhone, or downloading either bought or rented movies onto a portable DVD player. Here, there is a need to provide trustworthy protection of the rights of both parties; i.e. the seller’s copyright needs to be protected against piracy, while on the other hand it has been highlighted in literature the need to protect innocent buyers from being framed. Indeed, if either party cannot be assured that his rights are protected when he is involved in transactions within such environments, he would shy away and instead prefer for instance the more conventional non-digital means of buying and selling. And therefore without active participation from human users and object owners it is difficult to fully kick off the actual realization of intelligent environments. Zhang et al. recently proposed a buyer–seller watermarking protocol without a trusted third party based on secret sharing. While it is a nice idea to eliminate the need of a trusted third party by distributing secret shares between the buyer and the seller such that neither party has knowledge of the fingerprint embedded in a content, we show that it is possible for a buyer to remove his part of the fingerprint from the content he bought. This directly disproves the piracy tracing property claimed by the protocol. In fact, since piracy tracing is one of the earliest security applications of watermarking schemes, it raises doubts as to the soundness of the design of this protocol

A Study on Visually Encrypted Images for Rights Protection and Authentication

首都大学東京, 2014-03-25, 博士(工学), 甲第444号首都大学東

IMG-GUARD: Watermark Based Approach for Image Privacy in OSN Framework

A social networking service (also social networking site, SNS or social media) is an online platform that is used by people to build social networks or social relations with another persons who are share their own details or career interests, activities, backgrounds or real-life connections. Social networking sites are varied and they incorporate a range of new information and various tools such as availability personal computers, mobile devices such as tablet computers and smart phones, digital photo/video/sharing and "web logging" diary entries online (blogging). While Online Social Networks (OSNs) enable users to share photos easily, they also expose users to several privacy threats from both the OSNs and external entities. The current privacy controls on social networks are far from adequate, resulting in inappropriate flows of information when users fail to understand their privacy settings or OSNs fail to implement policies correctly. Social networks may be complicated because of privacy expectations when they reserve the right to analyze uploaded photos using automated watermarking technique. A user who uploads digital data such as image to their home page may wish to share it with only mutual friends, which OSNs partially satisfy with privacy settings. In this paper, we concentrate to solve the privacy violation problem occurred when images are published on the online social networks without the permission. According to such images are always shared after uploading process. Therefore, the digital image watermarking based on DWT co-efficient. Watermark bits are embedded in uploaded images. Watermarked images are shared in user homages can be difficult to misuse by other persons

Using Quaternion Fourier Transform in Steganography Systems

steganography is the discipline of exchanging information messages in such way that no one, other than the intended recipient, suspects the existence of the message.  The transmitted message can be in textual or multimedia form (audio, image or video) and can be hidden within cover media. Moreover, the hidden message can be in either plain or cipher form.  In steganography, the majority of hiding techniques are implemented either in spatial domain or in frequency domain of the cover media.   The current contribution introduces a new a steganography technique for hiding a textual message within a cover image.   Both the message and the cover image is converted to quaternion form and then only the quaternion message is converted to the frequency domain using Quaternion Fast Fourier Discrete Transform (QFFDT) technique.  Simple quaternion mathematics are used to combine the message (in quaternion frequency domain) within the cover image (in quaternion form).  Conversely, the hidden message can be revealed at the receiver using simple quaternion mathematics in presence of the original cover image.  The proposed method allows hiding a huge amount of data and it is much complicated against steganalysis compared to the traditional methods. The method is assessed using the known performance metrics and the obtained results show that it is robust and more secure against steganalysis attacks without affecting the consumed bandwidth of the communication channel