A survey on trust management for Internet of Things

For the past decade, query processing on relational data has been studied extensively, and many theoretical and practical solutions to query processing have been proposed under various scenarios. With the recent popularity of cloud computing, users now have the opportunity to outsource their data as well as the data management tasks to the cloud. However, due to the rise of various privacy issues, sensitive data (e.g., medical records) need to be encrypted before outsourcing to the cloud. In addition, query processing tasks should be handled by the cloud; otherwise, there would be no point to outsource the data at the first place. To process queries over encrypted data without the cloud ever decrypting the data is a very challenging task. In this paper, we focus on solving the k-nearest neighbor (kNN) query problem over encrypted database outsourced to a cloud: a user issues an encrypted query record to the cloud, and the cloud returns the k closest records to the user. We first present a basic scheme and demonstrate that such a naive solution is not secure. To provide better security, we propose a secure kNN protocol that protects the confidentiality of the data, user's input query, and data access patterns. Also, we empirically analyze the efficiency of our protocols through various experiments. These results indicate that our secure protocol is very efficient on the user end, and this lightweight scheme allows a user to use any mobile device to perform the kNN query.

Secure k-nearest neighbor query over encrypted data in outsourced environments

Secure k-Nearest Neighbor Query over Encrypted Data in Outsourced Environments

This book constitutes the refereed proceedings of the 30th Annual International Conference on the Theory and Applications of Cryptographic Techniques, EUROCRYPT 2011, held in Tallinn, Estonia, in May 2011. The 31 papers, presented together with 2 invited talks, were carefully reviewed and selected from 167 submissions. The papers are organized in topical sections on lattice-base cryptography, implementation and side channels, homomorphic cryptography, signature schemes, information-theoretic cryptography, symmetric key cryptography, attacks and algorithms, secure computation, composability, key dependent message security, and public key encryption.

Advances in cryptology : Eurocrypt 2011 : 30th annual international conference on the theory and applications of cryptographic techniques, Tallinn, Estonia, May 15-19, 2011 : proceedings

Nowadays, patients’ physiological data and medical records are outsourced to the medical cloud to help the patients and doctors to obtain valuable and reliable services, i.e., diagnosis decision and treatment recommendation, which provides subtle and precise guidance for medical cases. Neighborhood-based recommendation (NBR) provides an effective and vivid approach to finding like-minded nodes to generate recommendations, automating what is usually known as word of mouth. Unfortunately, both diverse medical data and outsource technology raise stringent privacy concerns since the patient data is generally associated with attribute sets which contain somewhat sensitive information, such as age, gender, epidemic, physiological data and clinic result etc. The great privacy-revealing risk will occur if this sensitive medical information is maliciously exploited by network eavesdroppers, untrusted cloud servers or doctors. Considering the above privacy-revealing issues in medical data, this article proposes a privacy-preserving optimization of neighborhood-based recommendation scheme (namely, PPO-NBR), which achieves a secure and privacy-preserving recommendation for medical-aided diagnosis and treatment without revealing the patients’ sensitive information. We propose a privacy-preserving medical graph construction protocol and a medical treatment recommendation protocol to implement the secure recommendation on the encrypted medical data, in which it employs BGN Cryptosystem as the building modular to encrypt data and then creatively applies graph theory to expand neighbors to search the best similar features, and uses BLS signature to ensure the authentication, and meanwhile, it deploys a ( $t,n$ ) oblivious transfer protocol to preserve the confidentiality of recommendation. A couple of experiments are implemented to evaluate the performance in terms of computational costs and communication overheads and indicate that our scheme is efficient and practical for medical-aided diagnosis.

A Privacy-Preserving Optimization of Neighborhood-Based Recommendation for Medical-Aided Diagnosis and Treatment

Quantum group blind signature scheme without entanglement

In cloud computing, secure analysis on outsourced encrypted data is a significant topic. As a frequently used query for online applications, secure k-nearest neighbors (k-NN) computation on encrypted cloud data has received much attention, and several solutions for it have been put forward. However, most existing schemes assume the query users are fully trusted and all query users share the total key which is used to encrypt and decrypt data owner's outsourced data. It is constitutionally not feasible in lots of real-world applications. In this paper, we propose a novel secure and efficient scheme for k-NN query on encrypted cloud data in which the key of data owner to encrypt and decrypt ousourced data will not be completely disclosed to any query user. Therefore, our scheme can efficiently support the secure k-NN query on encrypted cloud data even when query users are not trustworthy enough.

Secure k-NN computation on encrypted cloud data without sharing key with query users

We investigate the quantum sealed-bid auction protocol proposed by Zhao et al. (Opt Commun 283:1394, 2010). It uses M groups n-particle GHZ states to represent bids and a post-confirmation mechanism to guarantee the honesty of the quantum sealed-bid auction. However, in our opinion the protocol still does not complete the task of a sealed-bid auction fairly. It is shown that a large group of dishonest bidders can collude to obtain all the other one's secret bids before the opening phase of the auction with a probability polynomially close to one. Moreover, a simple feasible improvement of the protocol is proposed.

Cryptanalysis and melioration of secure quantum sealed-bid auction with post-confirmation

We investigate the fair quantum blind signature scheme proposed by Wang and Wen [Wang T Y and Wen Q Y 2010 Chin. Phys. B 19 060307], which uses the fundamental properties of quantum mechanics and the availability of a trusted arbitrator. However, in this paper, we find that the protocol cannot satisfy the property of non-forgeability even under the condition that the trusted arbitrator is totally credible. Moreover, a simple feasible suggestion for improving the protocol is proposed.

Cryptanalysis of fair quantum blind signatures

At EUROCRYPT 2011, Obana proposed a k-out-of-n secret sharing scheme capable of identifying up to t cheaters with probability 1 − e under the condition t < k/3 In that scheme, the share size |V i | satisfies |V i | = |S|/e, which is almost optimal However, Obana’s scheme is known to be vulnerable to attacks by rushing adversary who can observe the messages sent by the honest participants prior to deciding her own messages In this paper, we present a new scheme, which is secure against rushing adversary, with |V i | = |S|/e n − t + 1, assuming t < k/3 We note that the share size of our proposal is substantially smaller compared to |V i | = |S|(t + 1)3n /e 3n in the scheme by Choudhury at PODC 2012 when the secret is a single field element A modification of the later scheme is secure against rushing adversary under a weaker t < k/2 condition Therefore, our scheme demonstrates an improvement in share size achieved for the price of strengthening the assumption on t

Rui Xu

Papers

Quantum group blind signature scheme without entanglement

Secure k-NN computation on encrypted cloud data without sharing key with query users

Cryptanalysis and melioration of secure quantum sealed-bid auction with post-confirmation

Cryptanalysis of fair quantum blind signatures

On Cheater Identifiable Secret Sharing Schemes Secure against Rushing Adversary