In cloud computing, it is often assumed that cloud vendors are trusted; the guest Operating System (OS) and the Virtual Machine Monitor (VMM, also called Hypervisor) are secure. However, these assumptions are not always true in practice and existing approaches cannot protect the data privacy of applications when none of these parties are trusted. We investigate how to cope with a strong threat model which is that the cloud vendors, the guest OS, or the VMM, or both of them are malicious or untrusted, and can launch attacks against privacy of trusted user applications. This model is relevant because applications may be small enough to be formally verified, while the guest OS and VMM are too complex to be formally verified. Specifically, we present the design and analysis of an architectural solution which integrates a set of components on-chip to protect the memory of trusted applications from potential software and hardware based attacks from untrusted cloud providers, compromised guest OS, or malicious VMM. Full-system performance evaluation results show that the design only incurs 9 percent overhead on average, which is a small performance price that is paid for the substantial security gain.

The integration of cloud computing and Internet of Things (loT) is quickly becoming the key enabler for the digital transformation of the healthcare industry by offering comprehensive improvements in patient engagements, productivity and risk mitigation. This paradigm shift, while bringing numerous benefits and new opportunities to healthcare organizations, has raised a lot of security and privacy concerns. In this paper, we present a reliable, searchable and privacy-preserving e-healthcare system, which takes advantage of emerging cloud storage and IoT infrastructure and enables healthcare service providers (HSPs) to realize remote patient monitoring in a secure and regulatory compliant manner. Our system is built upon a novel dynamic searchable symmetric encryption scheme with forward privacy and delegated verifiability for periodically generated healthcare data. While the forward privacy is achieved by maintaining an increasing counter for each keyword at an IoT gateway, the data owner delegated verifiability comes from the combination of the Bloom filter and aggregate message authentication code. Moreover, our system is able to support multiple HSPs through either data owner assistance or delegation. The detailed security analysis as well as the extensive simulations on a large data set with millions of records demonstrate the practical efficiency of the proposed system for real world healthcare applications.

Information-centric networking (ICN), an alternative for future networking architecture, offers great benefits to both consumers and producers from various dimensions, such as scalability, security and mobility. Unlike IP packets containing geographically dependent and host-centric IP addresses, neither ICN interest packets (issued by a content requester or consumer) nor ICN data packets (generated by a content source or producer) by-default leak any geographical information, and thus both consumers' and producers' locations are perfectly hidden if the adversary does not eavesdrop on the network communication. Location privacy, however, does not necessarily imply the privacy of movement status (i.e., whether the object is moving or not) that might open the door to profiling attacks towards producers especially in an IoT-driven era where each individual may act as a producer. In this paper, we are motivated by the following critical questions: (i) Can ICN preserve privacy of the producer's movement status, and (ii) If not, how can we preserve privacy of movement status if a producer is moving. We survey the current ICN mobility mechanisms and find that most of them are vulnerable to attacks on privacy of the movement status. We propose a simple approach that can be used to prevent such attacks. The objective of this paper is to raise the security awareness for network architects/designers when designing mobility support mechanisms.

Recent studies shows that by the end of 2016 more than 60% of Internet traffic would be running on HTTPS. In presence of secure tunnels such as HTTPS, transparent caching solutions become in vain, as the application payload is encrypted by lower level security protocols. This paper addresses this issue and provides an alternate approach, for contents caching without compromising their security. There are three parts to our proposal. First, we propose two new IP layer primitives that allow routers to differentiate between IP and ICN flows. Second, we introduce DCAR (Dual-mode Content Aware Router), which is a traditional IP router enabled to understand the proposed IP primitives. Third, design of DISCS (DCAR based Information centric Secure Content Sharing) framework is proposed that leverages DCAR to allow content object caching along with security services that are comparable to HTTPS. Finally we share details on realizing such system.

We initiate the study of the following problem: Suppose Alice and Bob would like to outsource their encrypted private data sets to the cloud, and they also want to conduct the set intersection operation on their plaintext data sets. The straightforward solution for them is to download their outsourced cipher texts, decrypt the cipher texts locally, and then execute a commodity two-party set intersection protocol. Unfortunately, this solution is not practical. We therefore motivate and introduce the novel notion of Verifiable Delegated Set Intersection on outsourced encrypted data (VDSI). The basic idea is to delegate the set intersection operation to the cloud, while (i) not giving the decryption capability to the cloud, and (ii) being able to hold the misbehaving cloud accountable. We formalize security properties of VDSI and present a construction. In our solution, the computational and communication costs on the users are linear to the size of the intersection set, meaning that the efficiency is optimal up to a constant factor.

Shifting from host-oriented to data-oriented, information-centric networking (ICN) adopts several key design principles, e.g., in-network caching, to cope with the tremendous internet growth. In the ICN setting, data to be distributed can be cached by ICN routers anywhere and accessed arbitrarily by customers without data publishers' permission, which imposes new challenges when achieving data access control: (i) security: How can data publishers protect data confidentiality (either data cached by ICN routers or data accessed by authorized users) even when an authorized user's decryption key was revoked or compromised, and (ii) scalability: How can data publishers leverage ICN's promising features and enforce access control without complicated key management or extensive communication. This paper addresses these challenges by using the new proposed dual-phase encryption that uniquely combines the ideas from one-time decryption key, proxy re-encryption and all-or-nothing transformation, while still being able to leverage ICN's features. Our analysis and performance show that our solution is highly efficient and provable secure under the existing security model.

Named data networking (NDN) is a new paradigm for the future Internet wherein interest and data packets carry content names rather than the current IP paradigm of source and destination addresses. Security is built into NDN by embedding a public key signature in each data packet to enable verification of authenticity and integrity of the content. However, existing heavyweight signature generation and verification algorithms prevent universal integrity verification among NDN nodes, which may result in content pollution and denial of service attacks. Furthermore, caching and location-independent content access disables the capability of a content provider to control content access, e.g., who can cache a content and which end user or device can access it. We propose a lightweight integrity verification (LIVE) architecture, an extension to the NDN protocol, to address these two issues seamlessly. LIVE enables universal content signature verification in NDN with lightweight signature generation and verification algorithms. Furthermore, it allows a content provider to control content access in NDN nodes by selectively distributing integrity verification tokens to authorized nodes. We evaluate the effectiveness of LIVE with open source CCNx project. Our paper shows that LIVE only incurs average 10% delay in accessing contents. Compared with traditional public key signature schemes, the verification delay is reduced by over 20 times in LIVE.

Outsourcing private data and heavy computation tasks to the cloud may lead to privacy breach as attackers (e.g., malicious outsiders or cloud administrators) may correlate any relevant information to penetrate information of their interests. Therefore, how to preserve cloud users' privacy has been a top concern when adopting cloud solutions. In this paper, we investigate the identity privacy problem for the proxy re-encryption, which allows any third party (e.g., cloud) to re-encrypt ciphertexts in order to delegate the decryption right from one to another user. The relevant identity information, e.g., whose ciphertext was re-encrypted to the ciphertext under whose public key, may leak because re-encryption keys and ciphertexts (before and after re-encryption) are known to the third party. We review prior anonymity (identity privacy) notions, and find that these notions are either impractical or too weak. To address this problem thoroughly, we rigorously define the anonymity notion that not only embraces the prior anonymity notions but also captures the necessary anonymity requirement for practical applications. In addition, we propose a new and efficient proxy re-encryption scheme. The scheme satisfies the proposed anonymity notion under the Squared Decisional Bilinear Diffie-Hellman assumption and achieves security against chosen ciphertext attack under the Decisional Bilinear Diffie-Hellman assumption in the random oracle model. To the best of our knowledge, it is the first proxy re-encryption scheme attaining both chosen-ciphertext security and anonymity simultaneously.

It is common nowadays for data owners to outsource their data to the cloud. Since the cloud cannot be fully trusted, the outsourced data should be encrypted. This however brings a range of problems, such as: How should a data owner grant search capabilities to the data users? How can the authorized data users search over a data owner's outsourced encrypted data? How can the data users be assured that the cloud faithfully executed the search operations on their behalf? Motivated by these questions, we propose a novel cryptographic solution, called verifiable attribute-based keyword search (VABKS). The solution allows a data user, whose credentials satisfy a data owner's access control policy, to (i) search over the data owner's outsourced encrypted data, (ii) outsource the tedious search operations to the cloud, and (iii) verify whether the cloud has faithfully executed the search operations. We formally define the security requirements of VA B K S and describe a construction that satisfies them. Performance evaluation shows that the proposed schemes are practical and deployable.

Both security and efficiency are crucial to the success of cloud storage. So far, security and efficiency of cloud storage have been separately investigated as follows: On one hand, security notions such as Proof of Data Possession (PDP) and Proof of Retrievability (POR) have been introduced for detecting that the data stored in the cloud has been tampered with. On the other hand, the notion of Proof of Ownership (POW) has also been proposed to alleviate the cloud server from storing multiple copies of the same data, which could substantially reduce the consumption of both network bandwidth and server storage space. These two aspects are seemingly quite to the opposite of each other. In this paper, we show, somewhat surprisingly, that the two aspects can actually co-exist within the same framework. This is possible fundamentally because of the following insight: The public verifiability offered by PDP/POR schemes can be naturally exploited to achieve POW. This "one stone, two birds" phenomenon not only inspired us to propose the novel notion of Proof of Storage with Deduplication (POSD), but also guided us to design a concrete scheme that is provably secure in the Random Oracle model based on the Computational Diffie-Hellman (CDH) assumption.

Cloud computing is getting increasingly popular, but has yet to be widely adopted arguably because there are many security and privacy problems that have not been adequately addressed. A specific problem encountered in the context of cloud storage, where clients outsource their data (files) to untrusted cloud storage servers, is to convince the clients that their data are kept intact at the storage servers. An important approach to achieve this goal is called Proof of Retrievability (POR), by which a storage server can convince a client --- via a concise proof --- that its data can be recovered. However, existing POR solutions can only deal with static data (i.e., data items must be fixed), and actually are not secure when used to deal with dynamic data (i.e., data items need be inserted, deleted, and modified). Motivated by the need to securely deal with dynamic data, we propose the first dynamic POR scheme for this purpose. Moreover, we introduce a new property, called fairness, which is necessary and also inherent to the setting of dynamic data because, without ensuring it, a dishonest client could legitimately accuse an honest cloud storage server of manipulating its data. Our solution is based on two new tools, one is an authenticated data structure we call range-based 2-3 trees (rb23Tree for short), and the other is an incremental signature scheme we call hash-compress-and-sign (HCS for short). These tools might be of independent value as well.