Concrete Scheme Research Articles

Application and Exploration of Carbon Dioxide R744 as Refrigerant and Secondary Refrigerant in Refrigerating Unit of Commercial Super

In this paper, the cascade refrigeration system and the load cooling system of the natural working medium are integrated as one unit system, which can meet the needs of different temperature zones of refrigerating in supermarkets. The concrete implementation scheme of the unit system with R717 as high temperature refrigerant, CO2 as low temperature refrigerant and carrier refrigerant was designed. According to the actual load of commercial super, the design and calculation of NH3 refrigerant system, CO2 refrigerant carrier system and CO2 cryogenic system were carried out. Through calculation and testing, the ideal refrigeration effect of the unit is obtained. Compared with the traditional unit, the energy saving is 20%, emission reduction (translated into CO2 emission) is 40%, and the operation cost is reduced by 20%.

Cryptanalysis of an Online/Offline Certificateless Signature Scheme for Internet of Health Things

Recently, Khan et al. [An online-offline certificateless signature scheme for internet of health things,” Journal of Healthcare Engineering, vol. 2020] presented a new certificateless offline/online signature scheme for Internet of Health Things (IoHT) to fulfill the authenticity requirements of the resource-constrained environment of (IoHT) devices. The authors claimed that the newly proposed scheme is formally secured against Type-I adversary under the Random Oracle Model (ROM). Unfortunately, their scheme is insecure against adaptive chosen message attacks. It is demonstrated that an adversary can forge a valid signature on a message by replacing the public key. Furthermore, we performed a comparative analysis of the selective parameters including computation time, communication overhead, security, and formal proof by employing Evaluation based on Distance from Average Solution (EDAS). The analysis shows that the designed scheme of Khan et al. doesn’t have any sort of advantage over the previous schemes. Though, the authors utilized a lightweight hyperelliptic curve cryptosystem with a smaller key size of 80-bits. Finally, we give some suggestions on the construction of a concrete security scheme under ROM.

Enabling Reliable Keyword Search in Encrypted Decentralized Storage with Fairness

Blockchain has led the trend of decentralized applications and shown great use beyond cryptocurrencies. Decentralized storage such as Storj and Sia leverages blockchain to establish an open platform for sharing economy, which provides private and reliable file-outsourcing services. However, the ubiquitous keyword search function over encrypted files is yet to be supported. To enable this function, we first apply searchable encryption techniques to the decentralized setting. But this primitive can hardly ensure the service integrity. The reason is that decentralized storage commonly faces severe threats from both clients and service peers. Service peers may return partial or incorrect results, while clients may intentionally slander the service peers to avoid payments. To address these threats, we utilize the smart contract to record the logs of encrypted search (aka evidence) on the blockchain, and devise a fair protocol to handle disputes and issue fair payments. Using a dynamic-efficient searchable encryption scheme as an instantiation, we craft a concrete scheme that preserves encrypted search capability and enforces ecosystem healthiness, so that service peers are incentivized to make real efforts and jointly guarantee service reliability. We implement our scheme in Python and Solidity, and test its search performance and transaction costs on Ethereum.

Identity-Based Verifiable Aggregator Oblivious Encryption and Its Applications in Smart Grids

Verifiable aggregator oblivious encryption is a useful notion that not only allows an untrusted aggregator to compute aggregated data without learning any other information but also requires the aggregator to generate a proof of the aggregated data so that anyone can verify the accuracy. Since the aggregator does not learn data that may reveal users' private information and also cannot forge the aggregated data, verifiable aggregator oblivious encryption is suitable for privacy-preserving smart metering. However, NIST has recommended not using public-key-based cryptography in the smart grid because public-key cryptography cannot provide sufficient scalability. Thus, we propose a notion of identity-based verifiable aggregator oblivious encryption and design concrete schemes in this paper. We prove the aggregator oblivious security and aggregator unforgeability of our schemes via the smooth projective hash function and computational Diffie-Hellman assumption. Furthermore, based on our identity-based verifiable aggregator oblivious encryption scheme, we propose an identity-based data aggregation protocol for the smart grid and provide a security analysis in the context of seven typical attacks on smart grids. The implementation of our protocol via the Intel Edison platform shows that it is sufficiently lightweight for resource-constrained smart meters.

Learning Strikes Again: The Case of the DRS Signature Scheme

Lattice signature schemes generally require particular care when it comes to preventing secret information from leaking through signature transcript. For example, the Goldreich–Goldwasser–Halevi (GGH) signature scheme and the NTRUSign scheme were completely broken by the parallelepiped-learning attack of Nguyen and Regev (Eurocrypt 2006). Several heuristic countermeasures were also shown vulnerable to similar statistical attacks. At PKC 2008, Plantard, Susilo and Win proposed a new variant of GGH, informally arguing resistance to such attacks. Based on this variant, Plantard, Sipasseuth, Dumondelle and Susilo proposed a concrete signature scheme, called DRS, that is in the round 1 of the NIST post-quantum cryptography project. In this work, we propose yet another statistical attack and demonstrate a weakness of the DRS scheme: one can recover some partial information of the secret key from sufficiently many signatures. One difficulty is that, due to the DRS reduction algorithm, the relation between the statistical leak and the secret seems more intricate. We work around this difficulty by training a statistical model, using a few features that we designed according to a simple heuristic analysis. While we only recover partial secret coefficients, this information is easily exploited by lattice attacks, significantly decreasing their complexity. Concretely, we claim that, provided that $$100\,000$$ signatures are available, the secret key may be recovered using BKZ-138 for the first set of DRS parameters submitted to the NIST. This puts the security level of this parameter set below 80-bits (maybe even 70-bits), to be compared to an original claim of 128-bits. Furthermore, we review the DRS v2 scheme that is proposed to resist above statistical attack. For this countermeasure, while one may not recover partial secret coefficients exactly by learning, it seems feasible to gain some information on the secret key. Exploiting this information, we can still effectively reduce the cost of lattice attacks.

LTE-V2X Mode 3 scheduling based on adaptive spatial reuse of radio resources

LTE-V2X (also known as C-V2X or Cellular V2X) introduces direct or sidelink V2V (Vehicle to Vehicle) communications using the PC5 interface. LTE-V2X defines two modes (Mode 3 and Mode 4) for the management of radio resources. This study focuses on Mode 3 where the cellular network manages and allocates the radio resources for direct or sidelink V2V communications. Contrary to Mode 4, the 3GPP standards do not define any concrete scheduling scheme to allocate resources under Mode 3. In this context, this paper proposes a context-based scheduling scheme for LTE-V2X Mode 3 that exploits the geographical location of vehicles and dynamically configures its operation with the objective that all vehicles experience a similar level of interference when resources must be shared. The proposed scheduling scheme, referred to as DIRAC (aDaptive spatIal Reuse of rAdio resourCes), is validated analytically and its performance is evaluated through system level simulations. The evaluation shows that DIRAC outperforms existing LTE-V2X Mode 3 and Mode 4 scheduling schemes and ensures a more scalable and stable network operation as the channel load and congestion increases.

A Dynamic Searchable Symmetric Encryption Scheme for Multiuser with Forward and Backward Security

Dynamic Searchable Symmetric Encryption for Multiuser (M-DSSE) is an advanced form of symmetric encryption. It extends the traditional symmetric encryption to support the operations of adding and deleting the encrypted data and allow an authenticated group of data users to retrieve their respective desired encrypted data in the dynamic database. However, M-DSSE would suffer from the privacy concerns regarding forward and backward security. The former allows an attacker to identify the keywords contained in the added data by lunching file-injection attacks, while the latter allows to utilize the search results and the deleted data to learn the content. To our knowledge, these privacy concerns for M-DSSE have not been fully considered in the existing literatures. Taking account of this fact, we focus on the dynamic searchable symmetric encryption for multiuser meeting the needs of forward and backward security. In order to propose a concrete scheme, the primitives of Pseudorandom Functions (PRF) and the Homomorphic Message Authenticator (HMAC) are employed to construct the inverted index and update the search token. The proposed scheme is proven secure in the random model. And the performance analysis shows that the proposed scheme achieves the enhanced security guarantees at the reasonable price of efficiency.

Design of a hybrid model for construction of digital chaos and local synchronization

Dynamical degradation of digital chaos and security in chaotic synchronization are two bottleneck problems in chaos-based applications. Focusing on both of them, this paper studies the construction of digital chaotic systems without degeneration, as well as information leakage in synchronization of analog chaotic systems. A universal analog-digital hybrid mechanism is proposed, in which an analog chaotic system is introduced to construct digital chaos. Meanwhile, in order to achieve secure synchronization, the impulsive synchronization signals generated by the constructed digital chaotic systems have been used to control the local analog chaotic systems instead of sending a driving signal to the receiver. Remarkably, a previously unknown chaotic attractor has been discovered under such mutual control. The matching theoretical analyses are given to guarantee the validity of the constructed digital chaos and the synchronization of the analog chaotic systems. Simulation studies of a concrete scheme are conducted to illustrate the universality of the hybrid mechanism.

Realizing the Hayden-Preskill protocol with coupled Dicke models

Hayden and Preskill proposed a thought experiment that Bob can recover the information Alice throws into a black hole if he has a quantum computer entangled with the black hole, and Yoshida and Kitaev recently proposed a concrete decoding scheme. The parallel question is that after a small system is thermalized with a large system, how one can decode the initial state information with the help of two entangled many-body systems. Here we propose to realize this protocol in a physical system of two Dicke models, with two cavity fields prepared in a thermofield double state. We show that the Yoshida-Kitaev protocol allows us to read out the initial spin information after it is scrambled into the cavity. We show that the readout efficiency reaches a maximum when the model parameter is tuned to the regime where the system is the most chaotic, characterized by the shortest scrambling time in the out-of-time-ordered correlation function. Our proposal opens up the possibility of discussing this profound thought experiment in a realistic setting.

Topological and holonomic quantum computation based on second-order topological superconductors

Majorana fermions feature non-Abelian exchange statistics and promise fascinating applications in topological quantum computation. Recently, second-order topological superconductors (SOTSs) have been proposed to host Majorana fermions as localized quasiparticles with zero excitation energy, pointing out a new avenue to facilitate topological quantum computation. We provide a minimal model for SOTSs and systematically analyze the features of Majorana zero modes with analytical and numerical methods. We further construct the fundamental fusion principles of zero modes stemming from a single or multiple SOTS islands. Finally, we propose concrete schemes in different setups formed by SOTSs, enabling us to exchange and fuse the zero modes for non-Abelian braiding and holonomic quantum gate operations.

Efficient Boolean Keywords Search over Encrypted Cloud Data in Public Key Setting

Searchable public key encryption- (SPE-) supporting keyword search plays an important role in cloud computing for data confidentiality. The current SPE scheme mainly supports conjunctive or disjunctive keywords search which belongs to very basic query operations. In this paper, we propose an efficient and secure SPE scheme that supports Boolean keywords search, which is more advanced than the conjunctive and disjunctive keywords search. We first develop a keyword conversion method, which can change the index and Boolean keywords query into a group of vectors. Then, through applying a technique so-called dual pairing vector space to encrypt the obtained vectors, we propose a concrete scheme proven to be secure under chosen keyword attack. Finally, we put forward a detailed theoretical and experimental analysis to demonstrate the efficiency of our scheme.

Secure Identity-Based Blind Signature Scheme for Online Transactions

Today, more and more business activities are done through online transactions. How to protect the personal privacy of customers in online transactions has become an urgent issue. Blind signature (BS) is suitable for online transactions because it can hide the specific content of the signed message. The security proofs of most BS schemes are given in the random oracle model (ROM). As we all know, the cryptographic scheme that is proven to be secure in ROM may be insecure in practical applications. In this paper, we fist study the security requirements for identity-based BS (IBBS) scheme, then design a concrete IBBS scheme and show the security proofs in the standard model. Finally, we compare the proposed scheme with the other two BS schemes. Requiring only three pairing operations, the proposed scheme is much efficient and is suitable for online transactions.

Two-Factor Decryption: A Better Way to Protect Data Security and Privacy

Abstract Biometric information is unique to a human, so it would be desirable to use the biometric characteristic as the private key in a cryptographic system to protect data security and privacy. In this paper, we introduce a notion called two-factor decryption (TFD). Informally speaking, a TFD scheme is a variant of the public-key encryption (PKE) scheme. In a TFD scheme, messages are encrypted under public keys as that in a standard PKE scheme, but both private keys (i.e. the first factor) and biometric inputs (i.e. the second factor) are required to decrypt the ciphertexts and obtain the underlying plaintexts. We first describe a framework of TFD, and then define a formal security model for TFD. Thereafter, we present a generic construction on TFD based on the cryptographic primitives of linear sketch and functional encryption (FE) with certain properties and analyse its security. In addition, we give instantiations of TFD by applying concrete FE schemes into the generic construction and show their applications.

A linearly implicit energy-preserving exponential integrator for the nonlinear Klein-Gordon equation

In this paper, we generalize the exponential energy-preserving integrator proposed in the recent paper [SIAM J. Sci. Comput. 38 (2016) A1876–A1895] for conservative systems, which now becomes linearly implicit by further utilizing the idea of the scalar auxiliary variable approach. Comparing with the original exponential energy-preserving integrator which usually leads to a nonlinear algebraic system, our new method only involves a linear system with a constant coefficient matrix. Taking the nonlinear Klein-Gordon equation and the nonlinear Schrödinger equation for examples, we derive the concrete energy-preserving schemes and demonstrate their high efficiency through numerical experiments.

Experimental investigation and simplified stiffness degradation model of precast concrete shear wall with steel connectors

Premature damage of the post-cast concrete joints of precast concrete shear walls (PSWs) was observed in the past earthquakes due to the poor connection details and stress concentration of the wall-beam-slab joints. To avoid the potential failure, a new connection method featuring steel connectors, applied in the PSWs, is firstly proposed based on the plastic damage relocation design concept. Five 1/3 scaled specimens, including one monolithic concrete shear wall (MSW) and four PSWs, were constructed and tested under quasi-static cyclic loading. Seismic performances in terms of damage modes, drift ratio versus shear force behaviors, equivalent viscous damping ratio, deformation components, and stiffness degradation characteristics of PSWs were investigated. It shows that concrete cracks are developed at the bottom of the precast shear wall panel initially and its crack widths are decreased. The connection method can provide efficient stiffness and strength for the precast concrete shear wall system as no significant degradation of shear force occurs before a drift ratio of 1/50. Precast concrete shear wall having T-shaped with non-full length type connectors (TPSW-N) has the lowest cracking shear force and one having H-shaped connectors (HPSW) possesses a more stable lateral force-resisting capacity. The equivalent viscous damping ratios of the PSWs are higher than that of the MSW up to a drift ratio of 1/100. Among the PSWs, the HPSW shows the best seismic performance by comprehensively considering the damage mode, shear force characteristics and energy dissipation capacity. The flexural deformation at the middle of the precast shear wall panel is decreased compared with that of the wall panel of the MSW. The proposed connection method moves the critical region outside the week connection zones, which could be an alternative for the conventional post-cast concrete connection scheme. A simplified five-line stiffness degradation model of PSWs, controlled by elastic, cracking, yield, peak and ultimate points, is established and verified. The simplified model can be used to estimate the stiffness degradation properties of the proposed PSWs.

Secure multiparty learning from the aggregation of locally trained models

In many applications, multiple parties would benefit from a precise learning model trained from the aggregated dataset. However, the trivial method that all the data is aggregated into one datacenter and processed centrally is not appropriate when data privacy is a significant concern. In this paper, we propose a new framework for secure multi-party learning and construct a concrete scheme by incorporating aggregate signature and proxy re-encryption techniques. Unlike the previous solutions for multi-party privacy-preserving machine learning, we don't use encryption algorithm to encrypt the whole dataset or the intermediate values during the training process. In our scheme, secure verifiable computation delegation is utilized to privately label a public dataset from the aggregation of locally trained models. Using these newly generated labeled data items, the participants can update their learning models with great accuracy improvement. Further, we prove that the proposed scheme satisfies the desired security properties, and the experimental analysis on MNIST and HAM10000 shows that it is highly efficient.

A post-quantum hybrid encryption based on QC-LDPC codes in the multi-user setting

The encryption schemes based on coding theory are one of the most accredited choices in post-quantum scenario, where QC-LDPC codes are usually employed to construct concrete schemes due to the well security and good efficiency. In this work, we introduce a new IND-CCA secure multi-instance framework for code-based hybrid encryption primitive in the random oracle model, which is derived from our new multi-instance KEM and DEM building modules.We note that previous multi-instance KEM and DEM are usually derived from single-instance KEM and DEM, and hence suffers from large parameter sizes and security loss. Nevertheless, our multi-instance KEM is a direct construction based on a key generation function and a one-way trapdoor function, and our multi-instance DEM is constructed from a standard DEM and MAC with a tag in the input to achieve a tighter security loss. Finally, we present a IND-CCA secure multi-instance hybrid encryption scheme based on QC-LDPC codes in the random oracle model, where the scheme achieves small private key size and only consumes addition and multiplication operations over F2[x].

Heuristic decision of planned shop visit products based on similar reasoning method: From the perspective of organizational quality-specific immune

AbstractThe purpose of this study is to reduce the maintenance time, cost, and scheduling distance and to determine the maintenance priority of planned shop visit products. This study introduces the concept of maintenance map, establishes the evaluation indicators system of maintenance map from the perspective of organizational quality-specific immune, and puts forward two key dimensions named maintenance plan and technical support of maintenance map. Based on the theoretical framework, construct a heuristic decision model of planned shop visit products based on similar reasoning, set the maintenance services data of Harbin Dongan Engine Co., Ltd., as research objects, and use the concrete schemes and cases to solve and carry out an empirical analysis of the heuristic decision of planned shop visit products based on similar reasoning with the help of the ant colony algorithm; the empirical analysis results indicate that maintenance map and evaluation indicators system are the fundamental basis of the heuristic decision based on similar reasoning, the combinations of similar reasoning and ant colony algorithm can achieve the optimal heuristic decision of planned shop visit products, which have effectiveness, feasibility, and operability. This research will be conductive to give out the heuristic decision of scheduling schemes of planned shop visit products, which will be beneficial to enhance maintenance efficiency and quality, promote learning effects and learning pattern paths, and reduce maintenance scheduling distances of planned shop visit products from the aspects of theoretical framework guidance, empirical system enlightenment, and conceptual paradigm reference.

PKE-MET: Public-Key Encryption With Multi-Ciphertext Equality Test in Cloud Computing

Cloud computing enables users to remove the necessity of the need of local hardware architecture, which removes the burden of the users from high computation costs. Therefore, it has attracted much attention and research has been conducted heavily on it. To protect users’ privacy, data is usually encrypted prior to being sent to the cloud server. As the resulting system is unusable, since the cloud can no longer search throughout the data, new cryptographic primitive such as public-key encryption with equality test (PKEET) has been introduced. In PKEET, users can test whether the underlying messages of two ciphertexts encrypted under different public keys are equal or not without the need to decrypt those ciphertexts. This is a very useful tool, especially for the cloud database, since PKEET mainly focuses on the equality test between two ciphertexts. However, in practice, the cloud server may need to verify the equivalence among more than two ciphertexts. This leads to disclosing unnecessary information of users and redundant computation cost will also occur when using traditional PKEET schemes. How to make this more efficient and practical remains an interesting research problem. In this article, to solve the aforementioned problems by providing a novel concept of public-key encryption with multi-ciphertext equality test (PKE-MET). In PKE-MET, each ciphertext can designate a number <inline-formula><tex-math notation="LaTeX">$s$</tex-math></inline-formula> such that the cloud server can only perform equality test on this ciphertext with other <inline-formula><tex-math notation="LaTeX">$s-1$</tex-math></inline-formula> ciphertexts, where all their designated numbers are <inline-formula><tex-math notation="LaTeX">$s$</tex-math></inline-formula> . For PKE-MET, besides traditional OW-CPA and IND-CPA security, we specially define Number security. We instantiate PKE-MET to a concrete scheme and give its security proof. Furthermore, to enable the primitive to be more practical in applications, we extend it to the concept of PKE with flexible MET (PKE-FMET). In PKE-FMET, the cloud server can perform equality test on any number of ciphertexts as long as the maximum number of their designated numbers is less than or equal to the number of ciphertexts. We construct a PKE-FMET scheme based on our PKE-MET construction and prove its security under the defined security models. Besides, the performance analysis mainly of efficiency and security between our constructions and existing equality test schemes in cloud computing show that our proposed schemes are more efficient and secure in the multi-ciphertext scenario.

Comments on “Provably Secure Generalized Signcryption Scheme With Public Verifiability for Secure Data Transmission Between Resource-Constrained IoT Devices”

Very recently, Karati et al. presented a new generalized CLSC (gCLSC) to provide the functions of digital signature and encryption to fulfill the authenticity and confidentiality for the resource-constrained Internet-of-Things (IoT) devices. Karati et al. claimed that the newly proposed gCLSC supports the property of public verifiability and security of an ideal signcryption under the strong Diffie–Hellman and bilinear Diffie–Hellman inversion problems without the random oracle model. Unfortunately, their scheme is insecure with respect to unforgeability. It is demonstrated that any receiver or nonprivileged user can generate a valid signature or signcrypted ciphertext on any message. Finally, this article also points out the flaw in their unforgeability proof and gives some suggestions on the construction of a concrete scheme.