Visible to the public Biblio

Found 1586 results

Filters: Keyword is cryptography  [Clear All Filters]
2018-02-21
Waye, Lucas, Buiras, Pablo, Arden, Owen, Russo, Alejandro, Chong, Stephen.  2017.  Cryptographically Secure Information Flow Control on Key-Value Stores. Proceedings of the 2017 ACM SIGSAC Conference on Computer and Communications Security. :1893–1907.

We present Clio, an information flow control (IFC) system that transparently incorporates cryptography to enforce confidentiality and integrity policies on untrusted storage. Clio insulates developers from explicitly manipulating keys and cryptographic primitives by leveraging the policy language of the IFC system to automatically use the appropriate keys and correct cryptographic operations. We prove that Clio is secure with a novel proof technique that is based on a proof style from cryptography together with standard programming languages results. We present a prototype Clio implementation and a case study that demonstrates Clio's practicality.

Hadagali, C..  2017.  Multicore implementation of EME2 AES disk encryption algorithm using OpenMP. 2017 8th International Conference on Computing, Communication and Networking Technologies (ICCCNT). :1–6.

Volume of digital data is increasing at a faster rate and the security of the data is at risk while being transit on a network as well as at rest. The execution time of full disk encryption in large servers is significant because of the computational complexity associated with disk encryption. Hence it is necessary to reduce the execution time of full disk encryption from the application point of view. In this work a full disk encryption algorithm namely EME2 AES (Encrypt Mix Encrypt V2 Advanced Encryption Standard) is analyzed. The execution speed of this algorithm is reduced by means of multicore compatible parallel implementation which makes use of available cores. Parallel implementation is executed on a multicore machine with 8 cores and speed up on the multicore implementation is measured. Results show that the multicore implementation of EME2 AES using OpenMP is up to 2.85 times faster than sequential execution for the chosen infrastructure and data range.

Conti, F., Schilling, R., Schiavone, P. D., Pullini, A., Rossi, D., Gürkaynak, F. K., Muehlberghuber, M., Gautschi, M., Loi, I., Haugou, G. et al..  2017.  An IoT Endpoint System-on-Chip for Secure and Energy-Efficient Near-Sensor Analytics. IEEE Transactions on Circuits and Systems I: Regular Papers. 64:2481–2494.

Near-sensor data analytics is a promising direction for internet-of-things endpoints, as it minimizes energy spent on communication and reduces network load - but it also poses security concerns, as valuable data are stored or sent over the network at various stages of the analytics pipeline. Using encryption to protect sensitive data at the boundary of the on-chip analytics engine is a way to address data security issues. To cope with the combined workload of analytics and encryption in a tight power envelope, we propose Fulmine, a system-on-chip (SoC) based on a tightly-coupled multi-core cluster augmented with specialized blocks for compute-intensive data processing and encryption functions, supporting software programmability for regular computing tasks. The Fulmine SoC, fabricated in 65-nm technology, consumes less than 20mW on average at 0.8V achieving an efficiency of up to 70pJ/B in encryption, 50pJ/px in convolution, or up to 25MIPS/mW in software. As a strong argument for real-life flexible application of our platform, we show experimental results for three secure analytics use cases: secure autonomous aerial surveillance with a state-of-the-art deep convolutional neural network (CNN) consuming 3.16pJ per equivalent reduced instruction set computer operation, local CNN-based face detection with secured remote recognition in 5.74pJ/op, and seizure detection with encrypted data collection from electroencephalogram within 12.7pJ/op.

Silva, M. R., Zeferino, C. A..  2017.  Confidentiality and Authenticity in a Platform Based on Network-on-Chip. 2017 VII Brazilian Symposium on Computing Systems Engineering (SBESC). :225–230.

In many-core systems, the processing elements are interconnected using Networks-on-Chip. An example of on-chip network is SoCIN, a low-cost interconnect architecture whose original design did not take into account security aspects. This network is vulnerable to eavesdropping and spoofing attacks, what limits its use in systems that require security. This work addresses this issue and aims to ensure the security properties of confidentiality and authenticity of SoCIN-based systems. For this, we propose the use of security mechanisms based on symmetric encryption at the network level using the AES (Advanced Encryption Standard) model. A reference multi-core platform was implemented and prototyped in programmable logic aiming at performing experiments to evaluate the implemented mechanisms. Results demonstrate the effectiveness of the proposed solution in protecting the system against the target attacks. The impact on the network performance is acceptable and the silicon overhead is equivalent to other solutions found in the literature.

2018-02-15
Arora, A., Khanna, A., Rastogi, A., Agarwal, A..  2017.  Cloud security ecosystem for data security and privacy. 2017 7th International Conference on Cloud Computing, Data Science Engineering - Confluence. :288–292.

In the past couple of years Cloud Computing has become an eminent part of the IT industry. As a result of its economic benefits more and more people are heading towards Cloud adoption. In present times there are numerous Cloud Service providers (CSP) allowing customers to host their applications and data onto Cloud. However Cloud Security continues to be the biggest obstacle in Cloud adoption and thereby prevents customers from accessing its services. Various techniques have been implemented by provides in order to mitigate risks pertaining to Cloud security. In this paper, we present a Hybrid Cryptographic System (HCS) that combines the benefits of both symmetric and asymmetric encryption thus resulting in a secure Cloud environment. The paper focuses on creating a secure Cloud ecosystem wherein we make use of multi-factor authentication along with multiple levels of hashing and encryption. The proposed system along with the algorithm are simulated using the CloudSim simulator. To this end, we illustrate the working of our proposed system along with the simulated results.

Griffin, P. H..  2017.  Secure authentication on the Internet of Things. SoutheastCon 2017. :1–5.

This paper describes biometric-based cryptographic techniques for providing confidential communications and strong, mutual and multifactor authentication on the Internet of Things. The described security techniques support the goals of universal access when users are allowed to select from multiple choice alternatives to authenticate their identities. By using a Biometric Authenticated Key Exchange (BAKE) protocol, user credentials are protected against phishing and Man-in-the-Middle attacks. Forward secrecy is achieved using a Diffie-Hellman key establishment scheme with fresh random values each time the BAKE protocol is operated. Confidentiality is achieved using lightweight cryptographic algorithms that are well suited for implementation in resource constrained environments, those limited by processing speed, limited memory and power availability. Lightweight cryptography can offer strong confidentiality solutions that are practical to implement in Internet of Things systems, where efficient execution, and small memory requirements and code size are required.

Hufstetler, W. A., Ramos, M. J. H., Wang, S..  2017.  NFC Unlock: Secure Two-Factor Computer Authentication Using NFC. 2017 IEEE 14th International Conference on Mobile Ad Hoc and Sensor Systems (MASS). :507–510.

Our project, NFC Unlock, implements a secure multifactor authentication system for computers using Near Field Communication technology. The application is written in C\# with pGina. It implements an NFC authentication which replaces the standard Windows credentials to allow the use of an NFC tag and a passcode to authenticate the user. Unlike the most prevalent multifactor authentication methods, NFC authentication does not require a user wait for an SMS code to type into the computer. A user enters a passcode and scans the NFC tag to log in. In order to prevent the data from being hacked, the system encrypts the NFC tag ID and the passcode with Advanced Encryption Standard. Users can easily register an NFC tag and link it to their computer account. The program also has several extra features including text alerts, record keeping of all login and login attempts, and a user-friendly configuration menu. Initial tests show that the NFC-based multifactor authentication system has the advantage of improved security with a simplified login process.

Shah, R. H., Salapurkar, D. P..  2017.  A multifactor authentication system using secret splitting in the perspective of Cloud of Things. 2017 International Conference on Emerging Trends Innovation in ICT (ICEI). :1–4.

Internet of Things (IoT) is an emerging trend that is changing the way devices connect and communicate. Integration of cloud computing with IoT i.e. Cloud of Things (CoT) provide scalability, virtualized control and access to the services provided by IoT. Security issues are a major obstacle in widespread deployment and application of CoT. Among these issues, authentication and identification of user is crucial. In this study paper, survey of various authentication schemes is carried out. The aim of this paper is to study a multifactor authentication system which uses secret splitting in detail. The system uses exclusive-or operations, encryption algorithms and Diffie-Hellman key exchange algorithm to share key over the network. Security analysis shows the resistance of the system against different types of attacks.

Apostolaki, M., Zohar, A., Vanbever, L..  2017.  Hijacking Bitcoin: Routing Attacks on Cryptocurrencies. 2017 IEEE Symposium on Security and Privacy (SP). :375–392.

As the most successful cryptocurrency to date, Bitcoin constitutes a target of choice for attackers. While many attack vectors have already been uncovered, one important vector has been left out though: attacking the currency via the Internet routing infrastructure itself. Indeed, by manipulating routing advertisements (BGP hijacks) or by naturally intercepting traffic, Autonomous Systems (ASes) can intercept and manipulate a large fraction of Bitcoin traffic. This paper presents the first taxonomy of routing attacks and their impact on Bitcoin, considering both small-scale attacks, targeting individual nodes, and large-scale attacks, targeting the network as a whole. While challenging, we show that two key properties make routing attacks practical: (i) the efficiency of routing manipulation; and (ii) the significant centralization of Bitcoin in terms of mining and routing. Specifically, we find that any network attacker can hijack few (\textbackslashtextless;100) BGP prefixes to isolate 50% of the mining power-even when considering that mining pools are heavily multi-homed. We also show that on-path network attackers can considerably slow down block propagation by interfering with few key Bitcoin messages. We demonstrate the feasibility of each attack against the deployed Bitcoin software. We also quantify their effectiveness on the current Bitcoin topology using data collected from a Bitcoin supernode combined with BGP routing data. The potential damage to Bitcoin is worrying. By isolating parts of the network or delaying block propagation, attackers can cause a significant amount of mining power to be wasted, leading to revenue losses and enabling a wide range of exploits such as double spending. To prevent such effects in practice, we provide both short and long-term countermeasures, some of which can be deployed immediately.

Yonetani, R., Boddeti, V. N., Kitani, K. M., Sato, Y..  2017.  Privacy-Preserving Visual Learning Using Doubly Permuted Homomorphic Encryption. 2017 IEEE International Conference on Computer Vision (ICCV). :2059–2069.

We propose a privacy-preserving framework for learning visual classifiers by leveraging distributed private image data. This framework is designed to aggregate multiple classifiers updated locally using private data and to ensure that no private information about the data is exposed during and after its learning procedure. We utilize a homomorphic cryptosystem that can aggregate the local classifiers while they are encrypted and thus kept secret. To overcome the high computational cost of homomorphic encryption of high-dimensional classifiers, we (1) impose sparsity constraints on local classifier updates and (2) propose a novel efficient encryption scheme named doublypermuted homomorphic encryption (DPHE) which is tailored to sparse high-dimensional data. DPHE (i) decomposes sparse data into its constituent non-zero values and their corresponding support indices, (ii) applies homomorphic encryption only to the non-zero values, and (iii) employs double permutations on the support indices to make them secret. Our experimental evaluation on several public datasets shows that the proposed approach achieves comparable performance against state-of-the-art visual recognition methods while preserving privacy and significantly outperforms other privacy-preserving methods.

2018-02-14
Liu, Z., Liao, Y., Yang, X., He, Y., Zhao, K..  2017.  Identity-Based Remote Data Integrity Checking of Cloud Storage From Lattices. 2017 3rd International Conference on Big Data Computing and Communications (BIGCOM). :128–135.
In cloud storage, remote data integrity checking is considered as a crucial technique about data owners who upload enormous data to cloud server provider. A majority of the existing remote data integrity checking protocols rely on the expensive public key infrastructure. In addition, the verification of certificates needs heavy computation and communication cost. Meanwhile, the existing some protocols are not secure under the quantum computer attacks. However, lattice-based constructed cryptography can resist quantum computer attacks and is fairly effective, involving matrix-matrix or matrix-vector multiplications. So, we propose an identity-based remote data integrity checking protocol from lattices, which can eliminate the certificate management process and resist quantum computer attacks. Our protocol is completeness and provably secure based on the hardness small integer solution assumption. The presented scheme is secure against cloud service provider attacks, and leaks no any blocks of the stored file to the third party auditor during verification stage, namely the data privacy against the curiosity third party auditor attacks. The cloud service provider attack includes lost attack and tamper attack. Furthermore, the performance analysis of some protocols demonstrate that our protocol of remote data integrity checking is useful and efficient.
Mulhem, S., Adi, W., Mars, A., Prevelakis, V..  2017.  Chaining trusted links by deploying secured physical identities. 2017 Seventh International Conference on Emerging Security Technologies (EST). :215–220.
Efficient trust management between nodes in a huge network is an essential requirement in modern networks. This work shows few generic primitive protocols for creating a trusted link between nodes by deploying unclonable physical tokens as Secret Unknown Ciphers. The proposed algorithms are making use of the clone-resistant physical identity of each participating node. Several generic node authentication protocols are presented. An intermediate node is shown to be usable as a mediator to build trust without having influence on the resulting security chain. The physical clone-resistant identities are using our early concept of Secret Unknown Cipher (SUC) technique. The main target of this work is to show the particular and efficient trust-chaining in large networks when SUC techniques are involved.
Buchmann, N., Rathgeb, C., Baier, H., Busch, C., Margraf, M..  2017.  Enhancing Breeder Document Long-Term Security Using Blockchain Technology. 2017 IEEE 41st Annual Computer Software and Applications Conference (COMPSAC). 2:744–748.

In contrast to electronic travel documents (e.g. ePassports), the standardisation of breeder documents (e.g. birth certificates), regarding harmonisation of content and contained security features is in statu nascendi. Due to the fact that breeder documents can be used as an evidence of identity and enable the application for electronic travel documents, they pose the weakest link in the identity life cycle and represent a security gap for identity management. In this work, we present a cost efficient way to enhance the long-term security of breeder documents by utilizing blockchain technology. A conceptual architecture to enhance breeder document long-term security and an introduction of the concept's constituting system components is presented. Our investigations provide evidence that the Bitcoin blockchain is most suitable for breeder document long-term security.

Kravitz, D. W., Cooper, J..  2017.  Securing user identity and transactions symbiotically: IoT meets blockchain. 2017 Global Internet of Things Summit (GIoTS). :1–6.
Swarms of embedded devices provide new challenges for privacy and security. We propose Permissioned Blockchains as an effective way to secure and manage these systems of systems. A long view of blockchain technology yields several requirements absent in extant blockchain implementations. Our approach to Permissioned Blockchains meets the fundamental requirements for longevity, agility, and incremental adoption. Distributed Identity Management is an inherent feature of our Permissioned Blockchain and provides for resilient user and device identity and attribute management.
Raju, S., Boddepalli, S., Gampa, S., Yan, Q., Deogun, J. S..  2017.  Identity management using blockchain for cognitive cellular networks. 2017 IEEE International Conference on Communications (ICC). :1–6.
Cloud-centric cognitive cellular networks utilize dynamic spectrum access and opportunistic network access technologies as a means to mitigate spectrum crunch and network demand. However, furnishing a carrier with personally identifiable information for user setup increases the risk of profiling in cognitive cellular networks, wherein users seek secondary access at various times with multiple carriers. Moreover, network access provisioning - assertion, authentication, authorization, and accounting - implemented in conventional cellular networks is inadequate in the cognitive space, as it is neither spontaneous nor scalable. In this paper, we propose a privacy-enhancing user identity management system using blockchain technology which places due importance on both anonymity and attribution, and supports end-to-end management from user assertion to usage billing. The setup enables network access using pseudonymous identities, hindering the reconstruction of a subscriber's identity. Our test results indicate that this approach diminishes access provisioning duration by up to 4x, decreases network signaling traffic by almost 40%, and enables near real-time user billing that may lead to approximately 3x reduction in payments settlement time.
2018-02-06
Birnstill, P., Haas, C., Hassler, D., Beyerer, J..  2017.  Introducing Remote Attestation and Hardware-Based Cryptography to OPC UA. 2017 22nd IEEE International Conference on Emerging Technologies and Factory Automation (ETFA). :1–8.

In this paper we investigate whether and how hardware-based roots of trust, namely Trusted Platform Modules (TPMs) can improve the security of the communication protocol OPC UA (Open Platform Communications Unified Architecture) under reasonable assumptions, i.e. the Dolev-Yao attacker model. Our analysis shows that TPMs may serve for generating (RNG) and securely storing cryptographic keys, as cryptocoprocessors for weak systems, as well as for remote attestation. We propose to include these TPM functions into OPC UA via so-called ConformanceUnits, which can serve as building blocks of profiles that are used by clients and servers for negotiating the parameters of a session. Eventually, we present first results regarding the performance of a client-server communication including an additional OPC UA server providing remote attestation of other OPC UA servers.

Camenisch, J., Chen, L., Drijvers, M., Lehmann, A., Novick, D., Urian, R..  2017.  One TPM to Bind Them All: Fixing TPM 2.0 for Provably Secure Anonymous Attestation. 2017 IEEE Symposium on Security and Privacy (SP). :901–920.

The Trusted Platform Module (TPM) is an international standard for a security chip that can be used for the management of cryptographic keys and for remote attestation. The specification of the most recent TPM 2.0 interfaces for direct anonymous attestation unfortunately has a number of severe shortcomings. First of all, they do not allow for security proofs (indeed, the published proofs are incorrect). Second, they provide a Diffie-Hellman oracle w.r.t. the secret key of the TPM, weakening the security and preventing forward anonymity of attestations. Fixes to these problems have been proposed, but they create new issues: they enable a fraudulent TPM to encode information into an attestation signature, which could be used to break anonymity or to leak the secret key. Furthermore, all proposed ways to remove the Diffie-Hellman oracle either strongly limit the functionality of the TPM or would require significant changes to the TPM 2.0 interfaces. In this paper we provide a better specification of the TPM 2.0 interfaces that addresses these problems and requires only minimal changes to the current TPM 2.0 commands. We then show how to use the revised interfaces to build q-SDH-and LRSW-based anonymous attestation schemes, and prove their security. We finally discuss how to obtain other schemes addressing different use cases such as key-binding for U-Prove and e-cash.

Moukarzel, M., Eisenbarth, T., Sunar, B..  2017.  \#x03BC;Leech: A Side-Channel Evaluation Platform for IoT. 2017 IEEE 60th International Midwest Symposium on Circuits and Systems (MWSCAS). :25–28.

We propose $μ$Leech, a new embedded trusted platform module for next generation power scavenging devices. Such power scavenging devices are already widely deployed. For instance, the Square point-of-sale reader uses the microphone/speaker interface of a smartphone for communications and as power supply. While such devices are used as trusted devices in security critical applications in the wild, they have not been properly evaluated yet. $μ$Leech can securely store keys and provide cryptographic services to any connected smart phone. Our design also facilitates physical security analysis by providing interfaces to facilitate acquisition of power traces and clock manipulation attacks. Thus $μ$Leech empowers security researchers to analyze leakage in next generation embedded and IoT devices and to evaluate countermeasures before deployment.

Alghamdi, W., Schukat, M..  2017.  Advanced Methodologies to Deter Internal Attacks in PTP Time Synchronization Networks. 2017 28th Irish Signals and Systems Conference (ISSC). :1–6.

High accurate time synchronization is very important for many applications and industrial environments. In a computer network, synchronization of time for connected devices is provided by the Precision Time Protocol (PTP), which in principal allows for device time synchronization down to microsecond level. However, PTP and network infrastructures are vulnerable to cyber-attacks, which can de-synchronize an entire network, leading to potentially devastating consequences. This paper will focus on the issue of internal attacks on time synchronization networks and discuss how counter-measures based on public key infrastructures, trusted platform modules, network intrusion detection systems and time synchronization supervisors can be adopted to defeat or at least detect such internal attacks.

Vorobiev, E. G., Petrenko, S. A., Kovaleva, I. V., Abrosimov, I. K..  2017.  Organization of the Entrusted Calculations in Crucial Objects of Informatization under Uncertainty. 2017 XX IEEE International Conference on Soft Computing and Measurements (SCM). :299–300.

The urgent task of the organization of confidential calculations in crucial objects of informatization on the basis of domestic TPM technologies (Trusted Platform Module) is considered. The corresponding recommendations and architectural concepts of the special hardware TPM module (Trusted Platform Module) which is built in a computing platform are proposed and realize a so-called ``root of trust''. As a result it gave the organization the confidential calculations on the basis of domestic electronic base.

Detken, K. O., Jahnke, M., Rix, T., Rein, A..  2017.  Software-Design for Internal Security Checks with Dynamic Integrity Measurement (DIM). 2017 9th IEEE International Conference on Intelligent Data Acquisition and Advanced Computing Systems: Technology and Applications (IDAACS). 1:367–373.

Most security software tools try to detect malicious components by cryptographic hashes, signatures or based on their behavior. The former, is a widely adopted approach based on Integrity Measurement Architecture (IMA) enabling appraisal and attestation of system components. The latter, however, may induce a very long time until misbehavior of a component leads to a successful detection. Another approach is a Dynamic Runtime Attestation (DRA) based on the comparison of binary code loaded in the memory and well-known references. Since DRA is a complex approach, involving multiple related components and often complex attestation strategies, a flexible and extensible architecture is needed. In a cooperation project an architecture was designed and a Proof of Concept (PoC) successfully developed and evaluated. To achieve needed flexibility and extensibility, the implementation facilitates central components providing attestation strategies (guidelines). These guidelines define and implement the necessary steps for all relevant attestation operations, i.e. measurement, reference generation and verification.

Khan, M. F. F., Sakamura, K..  2017.  A Tamper-Resistant Digital Token-Based Rights Management System. 2017 International Carnahan Conference on Security Technology (ICCST). :1–6.

Use of digital token - which certifies the bearer's rights to some kind of products or services - is quite common nowadays for its convenience, ease of use and cost-effectiveness. Many of such digital tokens, however, are produced with software alone, making them vulnerable to forgery, including alteration and duplication. For a more secure safeguard for both token owner's right and service provider's accountability, digital tokens should be tamper-resistant as much as possible in order for them to withstand physical attacks as well. In this paper, we present a rights management system that leverages tamper-resistant digital tokens created by hardware-software collaboration in our eTRON architecture. The system features the complete life cycle of a digital token from generation to storage and redemption. Additionally, it provides a secure mechanism for transfer of rights in a peer-to-peer manner over the Internet. The proposed system specifies protocols for permissible manipulation on digital tokens, and subsequently provides a set of APIs for seamless application development. Access privileges to the tokens are strictly defined and state-of-the-art asymmetric cryptography is used for ensuring their confidentiality. Apart from the digital tokens being physically tamper-resistant, the protocols involved in the system are proven to be secure against attacks. Furthermore, an authentication mechanism is implemented that invariably precedes any operation involving the digital token in question. The proposed system presents clear security gains compared to existing systems that do not take tamper-resistance into account, and schemes that use symmetric key cryptography.

Sain, M., Bruce, N., Kim, K. H., Lee, H. J..  2017.  A Communication Security Protocol for Ubiquitous Sensor Networks. 2017 19th International Conference on Advanced Communication Technology (ICACT). :228–231.

The data accessibility anytime and anywhere is nowadays the key feature for information technology enabled by the ubiquitous network system for huge applications. However, security and privacy are perceived as primary obstacles to its wide adoption when it is applied to the end user application. When sharing sensitive information, personal s' data protection is the paramount requirement for the security and privacy to ensure the trustworthiness of the service provider. To this end, this paper proposes communication security protocol to achieve data protection when a user is sending his sensitive data to the network through gateway. We design a cipher content and key exchange computation process. Finally, the performance analysis of the proposed scheme ensure the honesty of the gateway service provider, since the user has the ability to control who has access to his data by issuing a cryptographic access credential to data users.

Bhattacharya, S., Kumar, C. R. S..  2017.  Ransomware: The CryptoVirus Subverting Cloud Security. 2017 International Conference on Algorithms, Methodology, Models and Applications in Emerging Technologies (ICAMMAET). :1–6.

Cloud computing presents unlimited prospects for Information Technology (IT) industry and business enterprises alike. Rapid advancement brings a dark underbelly of new vulnerabilities and challenges unfolding with alarming regularity. Although cloud technology provides a ubiquitous environment facilitating business enterprises to conduct business across disparate locations, security effectiveness of this platform interspersed with threats which can bring everything that subscribes to the cloud, to a halt raises questions. However advantages of cloud platforms far outweighs drawbacks and study of new challenges helps overcome drawbacks of this technology. One such emerging security threat is of ransomware attack on the cloud which threatens to hold systems and data on cloud network to ransom with widespread damaging implications. This provides huge scope for IT security specialists to sharpen their skillset to overcome this new challenge. This paper covers the broad cloud architecture, current inherent cloud threat mechanisms, ransomware vulnerabilities posed and suggested methods to mitigate it.

Tchernykh, A., Babenko, M., Chervyakov, N., Cortés-Mendoza, J. M., Kucherov, N., Miranda-López, V., Deryabin, M., Dvoryaninova, I., Radchenko, G..  2017.  Towards Mitigating Uncertainty of Data Security Breaches and Collusion in Cloud Computing. 2017 28th International Workshop on Database and Expert Systems Applications (DEXA). :137–141.

Cloud computing has become a part of people's lives. However, there are many unresolved problems with security of this technology. According to the assessment of international experts in the field of security, there are risks in the appearance of cloud collusion in uncertain conditions. To mitigate this type of uncertainty, and minimize data redundancy of encryption together with harms caused by cloud collusion, modified threshold Asmuth-Bloom and weighted Mignotte secret sharing schemes are used. We show that if the villains do know the secret parts, and/or do not know the secret key, they cannot recuperate the secret. If the attackers do not know the required number of secret parts but know the secret key, the probability that they obtain the secret depends the size of the machine word in bits that is less than 1/2(1-1). We demonstrate that the proposed scheme ensures security under several types of attacks. We propose four approaches to select weights for secret sharing schemes to optimize the system behavior based on data access speed: pessimistic, balanced, and optimistic, and on speed per price ratio. We use the approximate method to improve the detection, localization and error correction accuracy under cloud parameters uncertainty.