Private information retrieval (PIR) schemes allow a user to retrieve the ith bit of an n-bit data string x, replicated in k?2 databases (in the information-theoretic setting) or in k?1 databases (in the computational setting), while keeping the value of i private. The main cost measure for such a scheme is its communication complexity. In this paper we introduce a model of symmetrically-private information retrieval (SPIR), where the privacy of the data, as well as the privacy of the user, is guaranteed. That is, in every invocation of a SPIR protocol, the user learns only a single physical bit of x and no other information about the data. Previously known PIR schemes severely fail to meet this goal. We show how to transform PIR schemes into SPIR schemes (with information-theoretic privacy), paying a constant factor in communication complexity. To this end, we introduce and utilize a new cryptographic primitive, called conditional disclosure of secrets, which we believe may be a useful building block for the design of other cryptographic protocols. In particular, we get a k-database SPIR scheme of complexity O(n1/(2k?1)) for every constant k?2 and an O(logn)-database SPIR scheme of complexity O(log2n·loglogn). All our schemes require only a single round of interaction, and are resilient to any dishonest behavior of the user. These results also yield the first implementation of a distributed version of (n1)-OT (1-out-of-n oblivious transfer) with information-theoretic security and sublinear communication complexity.

Protecting Data Privacy in Private Information Retrieval Schemes.

Multiple cloud storage mechanism based on blockchain in smart homes

A survey on internet of things security from data perspectives

In the IoT (Internet of Things) environment, smart homes, smart grids, and telematics constantly generate data with complex attributes. These data have low heterogeneity and poor interoperability, which brings difficulties to data management and value mining. The promising combination of blockchain and the Internet of things as BCoT (blockchain of things) can solve these problems. This paper introduces an innovative method DCOMB (dual combination Bloom filter) to firstly convert the computational power of bitcoin mining into the computational power of query. Furthermore, this article uses the DCOMB method to build blockchain-based IoT data query model. DCOMB can implement queries only through mining hash calculation. This model combines the data stream of the IoT with the timestamp of the blockchain, improving the interoperability of data and the versatility of the IoT database system. The experiment results show that the random reading performance of DCOMB query is higher than that of COMB (combination Bloom filter), and the error rate of DCOMB is lower. Meanwhile, both DCOMB and COMB query performance are better than MySQL (My Structured Query Language).

Data Query Mechanism Based on Hash Computing Power of Blockchain in Internet of Things.

Information uprightness and capacity effectiveness are two essential necessities for distributed storage. Verification of Retrievability (POR) and Confirmation of Information Ownership (PDP) strategies guarantee information respectability for distributed storage. Evidence of Proprietorship (POW) enhances stockpiling proficiency by safely evacuating superfluously copied the information on the capacity server. Be that as it may, an insignificant blend of the two systems, with a specific end goal to accomplish both information trustworthiness and capacity proficiency, brings about non-minor duplication of metadata (i.e., validation labels), which repudiates the destinations of POW. Late endeavors to this issue present huge computational and correspondence costs and have likewise been demonstrated not secure. It requires another answer for bolster effective and secure information trustworthiness inspecting with capacity deduplication for distributed storage. In this paper, we take care of this open issue with a novel plan in view of strategies including polynomial-based validation labels and homomorphic straight authenticators. Our plan permits deduplication of both documents and their relating confirmation labels. Information respectability examining and capacity deduplication are accomplished all the while. Our proposed plan is likewise portrayed by consistent ongoing correspondence and computational cost on the client side. Open inspecting and group reviewing are both upheld. Henceforth, our proposed conspire beats existing POR and PDP plans while giving the extra usefulness of deduplication. We demonstrate the security of our proposed conspire in light of the Computational Diffie-Hellman issue, the Static Diffie-Hellman issue, and the t-Solid Diffie-Hellman issue. Numerical investigation and trial come about on Amazon AWS demonstrate that our plan is proficient and versatile.

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Secure and Constant Cost Public Cloud Storage Auditing with Deduplication

Based on Bell states, this paper proposes a semi-quantum protocol enabling the limited semi-quantum or “classical” user Bob to transmit the secret message to a fully quantum Alice directly. A classical user is restricted to measure, prepare, reorder and send quantum states only in the classical basis $$ \{ \left| 0 \right\rangle ,\left| 1 \right\rangle \} $$
 . The protocol must rely on the quantum Alice to produce Bell states, perform Bell basis measurement and store qubits, but the classical party Bob does not require quantum memory. Security and efficiency of the proposed schemes have been discussed. The analysis results show that the protocol is secure against some eavesdropping attacks and the qubit efficiency of the protocol is higher than the other related semi-quantum protocols.

Semi-quantum protocol for deterministic secure quantum communication using Bell states

Quantum secure direct communication allows one participant to transmit secret messages to another directly without generating a shared secret key first. In most of the existing schemes, quantum sec...

Two semi-quantum secure direct communication protocols based on Bell states

Recently, Xie et al. Int. J. Theor. Phys. 54, 3819–3824, (2015) proposed a Semi-quantum secret sharing protocol (SQSS). Yin et al. Int. J. Theor. Phys. 55: 4027–4035, (2016) pointed out that this protocol suffers from the intercept-resend attack. Yin et al. also proposed an improved protocol. However, we find out that Yin et al.’s paper has some problems, we analyze Yin et al.’s paper, then proposed the improved semi-quantum secret sharing protocol. Our protocol is more secure and efficient, most importantly, our protocol satisfies the condition of semi-quantum.

Cryptanalysis and Improvement of the Semi-quantum Secret Sharing Protocol

Semi-quantum protocol uses fewer resources and more flexible, which can still guarantee the unconditional safety. Based on Bell states, this paper first presents a semi-quantum key agreement protocol which allows two classical parties (Alice and Bob) to negotiate a shared secret key with the help of a quantum party (server). Classical parties only can perform reflection operation and measurement the qubit in the classical basis {|0〉, |1〉} in the protocol. During the protocol execution, Alice and Bob equally contribute in determining the final key and no one can manipulate and know the key prior to the other one. The security of the proposed protocol has been discussed, which analysis results show that the proposed protocol not only guarantees the security of the shared secret key but also assures the fairness property. We also analyze the efficiency of the proposed protocol. In addition, a semi-quantum private comparison protocol is proposed based on the key agreement protocol.

Semi-Quantum Key Agreement and Private Comparison Protocols Using Bell States

In this paper, we proposed two semi-quantum direct communication protocols based on Bell states. By pre-sharing two secret keys between two communicants, Alice with the advanced quantum ability can transmit secret messages to the classical Bob who can only perform the limited classical operations. At the same time, both sides of the communication can comfirm the legitimacy of each other’s identity. Security and qubit efficency analysis have been given. The analysis results show that the two protocols can resistant to several well-known attacks and their qubit efficency is higher than some current protocols.

Yan Chang

Papers

Semi-quantum protocol for deterministic secure quantum communication using Bell states

Two semi-quantum secure direct communication protocols based on Bell states

Cryptanalysis and Improvement of the Semi-quantum Secret Sharing Protocol

Semi-Quantum Key Agreement and Private Comparison Protocols Using Bell States

Two Semi-Quantum Direct Communication Protocols with Mutual Authentication Based on Bell States