Biblio

From the past few years cloud services are so popular and are being used by many people from various domains for various purposes such as data storage, e-mails, backing up data and much more. While there were many options to perform such things why did people choose cloud? The answer is clouds are more flexible, convenient, reliable and efficient. Coming to security of data over cloud, it is secure to store data over cloud rather than storing data locally as there is chance of some computer breakdown or any natural disaster may also occur. There are also many threats for data security over cloud namely data breaching, lack of access-key management and much more. As the data has been processed and being stored online for various purposes, there is a clear requirement for data security. Many organizations face various challenges while storing their data over cloud such as data leakages, account hijacking, insufficient credentials and so on. So to overcome these challenges and safeguard the data, various encryption techniques were implemented. However, even though encryption is used, the data still needs to be decrypted in order to do any type of operation. As a result, we must choose a manner in which the data can be analyzed, searched for, or used in any other way without needing to be decoded. So, the objective is to introduce a technique that goes right for the above conditions mentioned and for data security over cloud.

Fully homomorphic encryption technologies allow you to operate on encrypted data without disclosing it, therefore they have a lot of potential for solving personal data storage and processing issues. Because of the increased interest in these technologies, various software tools and libraries that allow completely homomorphic encryption have emerged. However, because this subject of cryptography is still in its early stages, standards and recommendations for the usage of completely homomorphic encryption algorithms are still being developed. The paper presents the main areas of application of homomorphic encryption. The analysis of existing developments in the field of homomorphic encryption is carried out. The analysis showed that existing library implementations do not support the division and subtraction operation. The analysis revealed the need to develop a library of fully homomorphic encryption, which allows performing all mathematical operations on them (addition, difference, multiplication and division), as well as the relevance of developing its own implementation of a library of homomorphic encryption on integers. Then, implement the development of a fully homomorphic encryption library in C++ and on an ESP 32 microcontroller. The ability to perform four operations (addition, difference, multiplication and division) on encrypted data will expand the scope of application of homomorphic encryption. A method of homomorphic division and subtraction is proposed that allows performing the division and subtraction operation on homomorphically encrypted data. The level of security, the types of operations executed, the maximum length of operands, and the algorithm's running time are all described as a consequence of numerical experimentation with parameters.

We suggest using Fully Homomorphic Encryption (FHE) to be used, not only to keep the privacy of information but also, to verify computations with no additional significant overhead, using only part of the variables length for verification. This method supports the addition of encrypted values as well as multiplication of encrypted values by the addition of their logarithmic representations and is based on a separation between hardware functionalities. The computer/server performs blackbox additions and is based on the separation of server/device/hardware, such as the enclave, that may deal with additions of logarithmic values and exponentiation. The main idea is to restrict the computer operations and to use part of the variable for computation verification (computation fingerprints) and the other for the actual calculation. The verification part holds the FHE value, of which the calculated result is known (either due to computing locally once or from previously verified computations) and will be checked against the returned FHE value. We prove that a server with bit computation granularity can return consistent encrypted wrong results even when the public key is not provided. For the case of computer word granularity the verification and the actual calculation parts are separated, the verification part (the consecutive bits from the LSB to the MSB of the variables) is fixed across all input vectors. We also consider the case of Single Instruction Multiple Data (SIMD) where the computation fingerprints index in the input vectors is fixed across all vectors.

What do we need to do to protect our personal information? IoT devices such as smartphones, smart watches, and home appliances are widespread. Encryption is required not only to prevent eavesdropping on communications but also to prevent information leakage from cloud services due to unauthorized access. Therefore, attention is being paid to fully homomorphic encryption (FHE) that allows addition and multiplication between ciphertexts. However, FHE with this convenient function has a drawback that the encryption requires huge volume of calculation and the ciphertext is large. Therefore, if FHE is used on a device with limited computational resources such as an IoT device, the load on the IoT device will be too heavy. In this research, we propose a system that can safely and effectively utilize data without imposing a load on IoT devices. In this system, somewhat homomorphic encryption (SHE), which is a lightweight cryptosystem compared with FHE, is combined with FHE. The results of the experiment confirmed that the load on the IoT device can be reduced to approximately 1/1400 compared to load of the system from previous research.

Fully homomorphic encryption (FHE) provides effective security assurance for privacy computing in cloud environments. But the existing FHE schemes are generally faced with challenges including using single-bit encryption and large ciphertext noise, which greatly affects the encryption efficiency and practicability. In this paper, a low-noise FHE scheme supporting multi-bit encryption is proposed based on the HAO scheme. The new scheme redesigns the encryption method without changing the system parameters and expands the plaintext space to support the encryption of integer matrices. In the process of noise reduction, we introduce a PNR method and use the subGaussian distribution theory to analyze the ciphertext noise. The security and the efficiency analysis show that the improved scheme can resist the chosen plaintext attack and effectively reduce the noise expansion rate. Comparative experiments show that the scheme has high encryption efficiency and is suitable for the privacy-preserving computation of integer matrices.

Keystroke dynamics is a behavioural biometric form of authentication based on the inherent typing behaviour of an individual. While this technique is gaining traction, protecting the privacy of the users is of utmost importance. Fully Homomorphic Encryption is a technique that allows performing computation on encrypted data, which enables processing of sensitive data in an untrusted environment. FHE is also known to be “future-proof” since it is a lattice-based cryptosystem that is regarded as quantum-safe. It has seen significant performance improvements over the years with substantially increased developer-friendly tools. We propose a neural network for keystroke analysis trained using differential privacy to speed up training while preserving privacy and predicting on encrypted data using FHE to keep the users' privacy intact while offering sufficient usability.

The inference results of neural network accelerators often involve personal privacy or business secrets in intelligent systems. It is important for the safety of convolutional neural network (CNN) accelerator to prevent the key data and inference result from being leaked. The latest CNN models have started to combine with fully homomorphic encryption (FHE), ensuring the data security. However, the computational complexity, data storage overhead, inference time are significantly increased compared with the traditional neural network models. This paper proposed a lightweight FHE scheme on fully-connected layer for CNN hardware accelerator to achieve security inference, which not only protects the privacy of inference results, but also avoids excessive hardware overhead and great performance degradation. Compared with state-of-the-art works, this work reduces computational complexity by approximately 90% and decreases ciphertext size by 87%∼95%.

To protect data in cloud servers, fully homomorphic encryption (FHE) is an effective solution. In addition to encrypting data, FHE allows a third party to evaluate arithmetic circuits (i.e., computations) over encrypted data without decrypting it, guaranteeing protection even during the calculation. However, FHE supports only addition and multiplication. Functions that cannot be directly represented by additions or multiplications cannot be evaluated with FHE. A naïve implementation of such arithmetic operations with FHE is a bit-wise operation that encrypts numerical data as a binary string. This incurs huge computation time and storage costs, however. To overcome this limitation, we propose an efficient protocol to evaluate multi-input functions with FHE using a lookup table. We extend our previous work, which evaluates a single-integer input function, such as f(x). Our extended protocol can handle multi-input functions, such as f(x,y). Thus, we propose a new method of constructing lookup tables that can evaluate multi-input functions to handle general functions. We adopt integer encoding rather than bit-wise encoding to speed up the evaluations. By adopting both permutation operations and a private information retrieval scheme, we guarantee that no information from the underlying plaintext is leaked between two parties: a cloud computation server and a decryptor. Our experimental results show that the runtime of our protocol for a two-input function is approximately 13 minutes, when there are 8,192 input elements in the lookup table. By adopting a multi-threading technique, the runtime can be further reduced to approximately three minutes with eight threads. Our work is more practical than a previously proposed bit-wise implementation, which requires 60 minutes to evaluate a single-input function.

This paper proposes a method that offers much higher security for Iseki's fully homomorphic encryption (FHE), a recently proposed secure computation scheme. The key idea is re-encrypting already encrypted data. This second encryption is executed using new common keys, whereby two or more encryptions offer much stronger security.

Fully homomorphic encryption (FHE) was one of the most prominent research topics of the last ten years. And it is considered as a major cryptographic tool in a secure and reliable cloud computing environment. The reason behind that because it allows computations over encrypted data, without decrypting the original message. This paper developed a new symmetric (FHE) algorithm based on Enhanced Matrix Operation for Randomization and Encryption (EMORE) algorithm using a chaotic system. The proposed algorithm was considered a noise-free algorithm. It generates the ciphertext in a floating-point number's format, overcomes the problem of plaintext ring and modular arithmetic operation in EMORE by the hardness of a chaotic system, and provides another level of security in terms of randomness properties, sensitivity to the initial condition, and large key size (\textbackslashtextgreater2100) of a chaotic system. Besides that, the proposed algorithm provides the confidentiality and privacy of outsourced data computing through homomorphism property of it. By using both numerical and statistical tests, these tests proved that the proposed algorithm has positive randomness properties and provide secure and reliable encryption (through encryption-decryption time, key sensitivity, keyspace, and correlation). Finally, the simulation results show that the execution time of the proposed algorithm is faster about 7.85 times than the EMORE algorithm.

In this paper, we propose the traceability of assets in a permissioned blockchain connected with a permissionless blockchain. We make traceability of assets in the permissioned blockchain be defined and be expressed as a hidden Markov model. There exists no dishonest increase and decrease of assets in this model. The condition is called balance. As we encrypt this model with fully homomorphic encryption and apply the zero knowledge proof of plaintext knowledge, we show that the trace-ability and balance of the permissioned blockchain are able to be proved in zero knowledge to the permissionless blockchain with concealing the asset allocation of the permissioned blockchain.

Cloud computing is a technology is where client require not to stress over the expense of equipment establishment and their support cost. Distributed computing is presently turned out to be most prominent innovation on account of its accessibility, ease and some different elements. Yet, there is a few issues in distributed computing, the principle one is security in light of the fact that each client store their valuable information on the system so they need their information ought to be shielded from any unapproved get to, any progressions that isn't done for client's benefit. To take care of the issue of Key administration, Key Sharing different plans have been proposed. The outsider examiner is the plan for key administration and key sharing. The primary preferred standpoint of this is the cloud supplier can encourage the administration which was accessible by the customary outsider evaluator and make it trustful. The outsider examining plan will be fizzled, if the outsider's security is endangered or of the outsider will be malignant. To take care of the issue, there is another modular for key sharing and key administration in completely Homomorphic Encryption conspire is outlined. In this paper we utilized the symmetric key understanding calculation named Diffie Hellman to make session key between two gatherings who need to impart and elliptic curve cryptography to create encryption keys rather than RSA and have utilized One Time Password (OTP) for confirming the clients.

We consider the secure search problem of retrieving from an unsorted data cost=(x\_1,...,xm) an item (i,xi) matching a given lookup value l (for a generic matching criterion either hardcoded or given as part of the query), where both input and output are encrypted by a Fully Homomorphic Encryption (FHE). The secure search problem is central in applications of secure outsourcing to an untrusted party ("the cloud"). Prior secure search algorithms on FHE encrypted data are realized by polynomials of degree Ømega(m), evaluated in Ømega(log m) sequential homomorphic multiplication steps (ie., multiplicative depth) even using an unbounded number of parallel processors. This is too slow with current FHE implementations, especially as the size of the array grows. We present the first secure search algorithm that is realized by a polynomial of logarithmic degree, log3 m, evaluated in O(log log m) sequential homomorphic multiplication steps (ie., multiplicative depth) using m parallel processors. We implemented our algorithm in an open source library based on HElib and ran experiments on Amazon's EC2 cloud with up to 100 processors. Our experiments show that we can securely search in m= millions of entries in less than an hour on a standard EC2 64-cores machine. We achieve our result by: (1) Employing modern data summarization techniques known as sketching for returning as output (the encryption of) a short sketch C from which the matching item (i,xi) can be decoded in time polynomial in log m. (2) Designing for this purpose a novel sketch that returns the first strictly-positive entry in a (not necessarily sparse) array of non-negative integers; this sketch may be of independent interest. (3) Suggesting a multi-ring evaluation of FHE for degree reduction from linear to logarithmic.

The huge amount of generated data offers special advantages mainly in dynamic and scalable systems. In fact, the data generator entities need to share the generated data with each other which leads to the use of cloud services. A cloud server is considered as an untrusted entity that offers many advantages such as large storing space, computation speed... etc. Hence, there is a need to cope with how to protect the stored data in the cloud server by proposing adaptive solutions. The main objective is how to provide an encryption scheme allowing the user to maintains some functions such as addition, multiplication and to preserve the order on the encrypted cloud data. Many algorithms and techniques are designed to manipulate the stored encrypted cloud data. This paper presents an adaptive and efficient fully homomorphic encryption technique to protect the user's data stored in the cloud, where the cloud server executes simple operations.

Fully homomorphic encryption (FHE) makes it easier for cloud computing to be consistent with privacy. But the efficiency of existing FHE schemes is still far from the actual needs. The main cause is that most of existing FHE schemes are single-bit encryption. Hiromasa, Abe and Okamoto (PKC 2015) reached the major milestone by constructing the first fully homomorphic encryption (FHE) scheme that encrypted message matrices (with single-bit matrices components) and supported homomorphic matrix addition and multiplication. In this paper, we propose a more efficient variant of Hiromasa, Abe and Okamoto with a lower factor noise-expansion factor for homomorphic multiplication from $\Theta$(poly(n)) to $\Theta$(1) and multi-bit matrices components.

In order to improve the efficiency of the existing homomorphic encryption method, based on the DGHV scheme, an improved fully homomorphic scheme over the integer is proposed. Under the premise of ensuring data owner and user data security, the scheme supports the addition and multiplication operations of ciphertext, and ensures faster execution efficiency and meets the security requirements of cloud computing. Security analysis shows that our scheme is safe. Performance assessment demonstrates that our scheme can more efficiently implement data than DGHV scheme.

The expeditious expansion of the networking technologies have remarkably driven the usage of the distributedcomputing as well as services, such as task offloading to the cloud. However, security and privacy concerns are restricting the implementations of cloud computing because of the threats from both outsiders and insiders. The primary alternative of protecting users' data is developing a Fully Homomorphic Encryption (FHE) scheme, which can cover both data protections and data processing in the cloud. Despite many previous attempts addressing this approach, none of the proposed work can simultaneously satisfy two requirements that include the non-noise accuracy and an efficiency execution. This paper focuses on the issue of FHE design and proposes a novel FHE scheme, which is called Optimal Fully Homomorphic Encryption (O-FHE). Our approach utilizes the properties of the Kronecker Product (KP) and designs a mechanism of achieving FHE, which consider both accuracy and efficiency. We have assessed our scheme in both theoretical proofing and experimental evaluations with the confirmed and exceptional results.

Damgard et al. proposed a new primitive called access control encryption (ACE) [6] which not only protects the privacy of the message, but also controls the ability of the sender to send the message. We will give a new construction based on the Learning with Error (LWE) assumption [12], which is one of the two open problems in [6]. Although there are many public key encryption schemes based on LWE and supporting homomorphic operations. We find that not every scheme can be used to build ACE. In order to keep the security and correctness of ACE, the random constant chosen by the sanitizer should satisfy stricter condition. We also give a different security proof of ACE based on LWE from it based on DDH. We will see that although the modulus of LWE should be super-polynomial, the ACE scheme is still as secure as the general public key encryption scheme based on the lattice [5].

Digital forensic investigators today are faced with numerous problems when recovering footprints of criminal activity that involve the use of computer systems. Investigators need the ability to recover evidence in a forensically sound manner, even when criminals actively work to alter the integrity, veracity, and provenance of data, applications and software that are used to support illicit activities. In many ways, operating systems (OS) can be strengthened from a technological viewpoint to support verifiable, accurate, and consistent recovery of system data when needed for forensic collection efforts. In this paper, we extend the ideas for forensic-friendly OS design by proposing the use of a practical form of computing on encrypted data (CED) and computing with encrypted functions (CEF) which builds upon prior work on component encryption (in circuits) and white-box cryptography (in software). We conduct experiments on sample programs to provide analysis of the approach based on security and efficiency, illustrating how component encryption can strengthen key OS functions and improve tamper-resistance to anti-forensic activities. We analyze the tradeoff space for use of the algorithm in a holistic approach that provides additional security and comparable properties to fully homomorphic encryption (FHE).

The challenge of maintaining confidentiality of stored and processed data in a remote database or cloud is quite urgent. Using homomorphic encryption may solve the problem, because it allows to compute some functions over encrypted data without preliminary deciphering of data. Fully homomorphic encryption schemes have a number of limitations such as accumulation of noise and increase of ciphertext extension during performing operations, the range of operations is limited. Nowadays a lot of homomorphic encryption schemes and their modifications have been investigated, so more than 25 reports on homomorphic encryption schemes have already been published on Cryptology ePrint Archive for 2016. We propose an overview of current Fully Homomorphic Encryption Schemes and analyze specific operations for databases which homomorphic cryptosystems allow to perform. We also investigate the possibility of sorting over encrypted data and present our approach to compare data encrypted by Multi-bit FHE scheme.

Private Set Intersection (PSI) is a cryptographic technique that allows two parties to compute the intersection of their sets without revealing anything except the intersection. We use fully homomorphic encryption to construct a fast PSI protocol with a small communication overhead that works particularly well when one of the two sets is much smaller than the other, and is secure against semi-honest adversaries. The most computationally efficient PSI protocols have been constructed using tools such as hash functions and oblivious transfer, but a potential limitation with these approaches is the communication complexity, which scales linearly with the size of the larger set. This is of particular concern when performing PSI between a constrained device (cellphone) holding a small set, and a large service provider (e.g. WhatsApp), such as in the Private Contact Discovery application. Our protocol has communication complexity linear in the size of the smaller set, and logarithmic in the larger set. More precisely, if the set sizes are Ny textless Nx, we achieve a communication overhead of O(Ny log Nx). Our running-time-optimized benchmarks show that it takes 36 seconds of online-computation, 71 seconds of non-interactive (receiver-independent) pre-processing, and only 12.5MB of round trip communication to intersect five thousand 32-bit strings with 16 million 32-bit strings. Compared to prior works, this is roughly a 38–115x reduction in communication with minimal difference in computational overhead.

The emergence of cloud computing allowed different IT services to be outsourced to cloud service providers (CSP). This includes the management and storage of user's structured data called Database as a Service (DBaaS). However, DBaaS requires users to trust the CSP to protect their data, which is inherent in all cloud-based services. Enterprises and Small-to-Medium Businesses (SMB) see this as a roadblock in adopting cloud services (and DBaaS) because they do not have full control of the security and privacy of the sensitive data they are storing on the cloud. One of the solutions is for the data owners to store their sensitive data in the cloud's storage services in encrypted form. However, to take full advantage of DBaaS, there should be a solution to manage the structured data while it is encrypted. Upcoming technologies like Secure Multi-Party Computing (MPC) and Fully Homomorphic Encryption (FHE) are recent advances in security that allow computation on encrypted data. FHE is considered as the holy grail of cryptography and the original blue print's processing performance is in the order of 1014 times longer than without encryption. Our work gives an insight on how far the state-of-the-art is into realizing it into a practical and viable solution for cloud computing data services. We achieved this by comparing two types of encrypted database management system (DBMS). We performed well-known complex database queries and measured the performance results of the two DBMS. We used an FHE-encrypted relational DBMS (RDBMS) and for specific query sets it takes only a few milliseconds, and the highest is in the order of 104 times longer than encrypted object-oriented DBMS (OODBMS). Aside from focusing on performance of the two databases, we also evaluated the network resource usage, standards availability, and application integration.

Intellectual Property (IP) verification is a crucial component of System-on-Chip (SoC) design in the modern IC design business model. Given a globalized supply chain and an increasing demand for IP reuse, IP theft has become a major concern for the IC industry. In this paper, we address the trust issues that arise between IP owners and IP users during the functional verification of an IP core. Our proposed scheme ensures the privacy of IP owners and users, by a) generating a privacy-preserving version of the IP, which is functionally equivalent to the original design, and b) employing homomorphically encrypted input vectors. This allows the functional verification to be securely outsourced to a third-party, or to be executed by either parties, while revealing the least possible information regarding the test vectors and the IP core. Experiments on both combinational and sequential benchmark circuits demonstrate up to three orders of magnitude IP verification slowdown, due to the computationally intensive fully homomorphic operations, for different security parameter sizes.