Image Privacy Protection with Secure JPEG Transmorphing

Thanks to advancements in smart mobile devices and social media platforms, sharing photos and experiences has significantly bridged our lives, allowing us to stay connected despite distance and other barriers. However, concern on privacy has also been raised, due to not only mistakes or ignorance of impact of careless sharing but also complex infrastructures and cross-use of social media content. In this paper, we present secure JPEG Transmorphing, a flexible framework for protecting image visual privacy in a secure, reversible, fun and personalized manner. With secure JPEG Transmorphing, the protected image is also backwards compatible with JPEG, the most commonly used image format. Experiments have been performed and results show that the proposed method provides a near lossless image reconstruction, a controllable level of storage overhead, and a good degree of privacy protection and subjective pleasantness

Approximate Thumbnail Preserving Encryption

Thumbnail preserving encryption (TPE) was suggested by Wright et al. as a way to balance privacy and usability for online image sharing. The idea is to encrypt a plaintext image into a ciphertext image that has roughly the same thumbnail as well as retaining the original image format. At the same time, TPE allows users to take advantage of much of the functionality of online photo management tools, while still providing some level of privacy against the service provider. In this work we present three new approximate TPE encryption schemes. In our schemes, ciphertexts and plaintexts have perceptually similar, but not identical, thumbnails. Our constructions are the first TPE schemes designed to work well with JPEG compression. In addition, we show that they also have provable security guarantees that characterize precisely what information about the plaintext is leaked by the ciphertext image. We empirically evaluate our schemes according to the similarity of plaintext and ciphertext thumbnails, increase in file size under JPEG compression, preservation of perceptual image hashes, among other aspects. We also show how approximate TPE can be an effective tool to thwart inference attacks by machine-learning image classifiers, which have shown to be effective against other image obfuscation techniques

Privacy-Friendly Photo Sharing and Relevant Applications Beyond

Popularization of online photo sharing brings people great convenience, but has also raised concerns for privacy. Researchers proposed various approaches to enable image privacy, most of which focus on encrypting or distorting image visual content. In this thesis, we investigate novel solutions to protect image privacy with a particular emphasis on online photo sharing. To this end, we propose not only algorithms to protect visual privacy in image content but also design of architectures for privacy-preserving photo sharing. Beyond privacy, we also explore additional impacts and potentials of employing daily images in other three relevant applications. First, we propose and study two image encoding algorithms to protect visual content in image, within a Secure JPEG framework. The first method scrambles a JPEG image by randomly changing the signs of its DCT coefficients based on a secret key. The second method, named JPEG Transmorphing, allows one to protect arbitrary image regions with any obfuscation, while secretly preserving the original image regions in application segments of the obfuscated JPEG image. Performance evaluations reveal a good degree of storage overhead and privacy protection capability for both methods, and particularly a good level of pleasantness for JPEG Transmorphing, if proper manipulations are applied. Second, we investigate the design of two architectures for privacy-preserving photo sharing. The first architecture, named ProShare, is built on a public key infrastructure (PKI) integrated with a ciphertext-policy attribute-based encryption (CP-ABE), to enable the secure and efficient access to user-posted photos protected by Secure JPEG. The second architecture is named ProShare S, in which a photo sharing service provider helps users make photo sharing decisions automatically based on their past decisions using machine learning. The photo sharing service analyzes not only the content of a user's photo, but also context information about the image capture and a prospective requester, and finally makes decision whether or not to share a particular photo to the requester, and if yes, at which granularity. A user study along with extensive evaluations were performed to validate the proposed architecture. In the end, we research into three relevant topics in regard to daily photos captured or shared by people, but beyond their privacy implications. In the first study, inspired by JPEG Transmorphing, we propose an animated JPEG file format, named aJPEG. aJPEG preserves its animation frames as application markers in a JPEG image and provides smaller file size and better image quality than conventional GIF. In the second study, we attempt to understand the impact of popular image manipulations applied in online photo sharing on evoked emotions of observers. The study reveals that image manipulations indeed influence people's emotion, but such impact also depends on the image content. In the last study, we employ a deep convolutional neural network (CNN), the GoogLeNet model, to perform automatic food image detection and categorization. The promising results obtained provide meaningful insights in design of automatic dietary assessment system based on multimedia techniques, e.g. image analysis

Hardware JPEG Decompression

Due to the ever increasing popularity of mobile devices, and the growing number of pixels in digital photography, there becomes a strain on viewing one\u27s own photos. Similar to Desktop PCs, a common trend occurring in the mobile market to compensate for the increased computational requirements is faster and multi-processor systems. The observation that the number of transistors in integrated circuits doubles approximately every 18-24 months is known as Moore\u27s law. Some believe that this trend, Moore\u27s law, is plateauing which enforces alternate methods to aid in computation. This thesis explores supplementing the processor with a dedicated hardware module to reduce its workload. This provides a software-hardware combination that can be utilized when large and long computations are needed, such as in the decompression of high pixel count JPEG images. The results show that this proposed architecture decreases the viewing time of JPEG images significantly

Balancing Image Privacy and Usability with Thumbnail-Preserving Encryption

In this paper, we motivate the need for image encryption techniques that preserve certain visual features in images and hide all other information, to balance privacy and usability in the context of cloud-based image storage services. In particular, we introduce the concept of ideal or exact Thumbnail-Preserving Encryption (TPE), a special case of format-preserving encryption, and present a concrete construction. In TPE, a ciphertext is itself an image that has the same thumbnail as the plaintext (unencrypted) image, but that provably leaks nothing about the plaintext beyond its thumbnail. We provide a formal security analysis for the construction, and a prototype implementation to demonstrate compatibility with existing services. We also study the ability of users to distinguish between thumbnail images preserved by TPE. Our findings indicate that TPE is an efficient and promising approach to balance usability and privacy concerns for images. Our code and a demo are available at http://photoencryption.org

Images on the Move

In contemporary society, digital images have become increasingly mobile. They are networked, shared on social media, and circulated across small and portable screens. Accordingly, the discourses of spreadability and circulation have come to supersede the focus on production, indexicality, and manipulability, which had dominated early conceptions of digital photography and film. However, the mobility of images is neither technologically nor conceptually limited to the realm of the digital. The edited volume re-examines the historical, aesthetical, and theoretical relevance of image mobility. The contributors provide a materialist account of images on the move - ranging from wired photography to postcards to streaming media

Images on the Move: Materiality - Networks - Formats

In contemporary society, digital images have become increasingly mobile. They are networked, shared on social media, and circulated across small and portable screens. Accordingly, the discourses of spreadability and circulation have come to supersede the focus on production, indexicality, and manipulability, which had dominated early conceptions of digital photography and film. However, the mobility of images is neither technologically nor conceptually limited to the realm of the digital. The edited volume re-examines the historical, aesthetical, and theoretical relevance of image mobility. The contributors provide a materialist account of images on the move - ranging from wired photography to postcards to streaming media

JPEG: the quadruple object

The thesis, together with its practice-research works, presents an object-oriented perspective on the JPEG standard. Using the object-oriented philosophy of Graham Harman as a theoretical and also practical starting point, the thesis looks to provide an account of the JPEG digital object and its enfolding within the governmental scopic regime. The thesis looks to move beyond accounts of digital objects and protocols within software studies that position the object in terms of issues of relationality, processuality and potentiality. From an object-oriented point of view, the digital object must be seen as exceeding its relations, as actual, present and holding nothing in reserve. The thesis presents an account of JPEG starting from that position as well as an object-oriented account of JPEG’s position within the distributed, governmental scopic regime via an analysis of Facebook’s Timeline, tagging and Haystack systems. As part of a practice-research project, the author looked to use that perspective within photographic and broader imaging practices as a spur to new work and also as a “laboratory” to explore Harman’s framework. The thesis presents the findings of those “experiments” in the form of a report alongside practice-research eBooks. These works were not designed to be illustrations of the theory, nor works to be “analysed”. Rather, following the lead of Ian Bogost and Mark Amerika, they were designed to be “philosophical works” in the sense of works that “did” philosophy

JPEG: the quadruple object

The thesis, together with its practice-research works, presents an object-oriented perspective on the JPEG standard. Using the object-oriented philosophy of Graham Harman as a theoretical and also practical starting point, the thesis looks to provide an account of the JPEG digital object and its enfolding within the governmental scopic regime. The thesis looks to move beyond accounts of digital objects and protocols within software studies that position the object in terms of issues of relationality, processuality and potentiality. From an object-oriented point of view, the digital object must be seen as exceeding its relations, as actual, present and holding nothing in reserve. The thesis presents an account of JPEG starting from that position as well as an object-oriented account of JPEG’s position within the distributed, governmental scopic regime via an analysis of Facebook’s Timeline, tagging and Haystack systems. As part of a practice-research project, the author looked to use that perspective within photographic and broader imaging practices as a spur to new work and also as a “laboratory” to explore Harman’s framework. The thesis presents the findings of those “experiments” in the form of a report alongside practice-research eBooks. These works were not designed to be illustrations of the theory, nor works to be “analysed”. Rather, following the lead of Ian Bogost and Mark Amerika, they were designed to be “philosophical works” in the sense of works that “did” philosophy