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With homomorphic encryption (HE), data can be processed in its encrypted form in the cloud computing (CC). This HE property can be considered as a useful solution to get over some concerns limiting the widespread adoption of CC services. Nevertheless, since CC environments are threatened by outsider and insider security attacks and since cloud consumers oftentimes access to CC services using resource-limited devices, the HE schemes need to be promoted in terms of security level and running time to work effectively. In El Makkaoui et al. (2016 international conference on big data and advanced wireless technologies, BDAW 2016, 2016b), we boosted the main Paillier’s scheme at security level by proposing a variant of the scheme called Cloud–Paillier. The proposed scheme addresses an exception of the Paillier’s scheme, supports the additive homomorphism over the integers and withstands more confidentiality attacks. For fast decryption, herein, we propose two fast variants of the Cloud–Paillier scheme. The proposed variants use moduli formed of $$k \ge 2$$k≥2distinct primes. The first variant utilizes the Chinese remainder theorem to decrypt. Whereas, the second variant sightly modifies the from of the Cloud–Paillier’s encryption algorithm and decrypts as in the Cloud–Paillier. Theoretical and simulation outcomes show that the suggested variants give a large decryption speed-up over the Cloud–Paillier while preserving a recommended security level.

Background: Cloud computing environment is a novel paradigm in which the services are hosted, delivered and managed over the internet. Tasks scheduling problem in the cloud has become a very interesting research area. However, the problem is more complex and challenging due to the dynamic nature of cloud and users’ needs as well as cloud providers’ requirements including the quality of service, users’ priorities and computing capabilities. Objective: The main objective is to solve the problem of tasks scheduling through an algorithm which can not only improves the client satisfaction, but also allows cloud service provider to gain maximum profit and ensure that the cloud resources are utilized efficiently. Method: (a) Optimization of the waiting time and the queue length. (b) Distribution of all requests into a novel queueing system in a dynamic manner based on a decision threshold. (c) Assignment of requests to VMs based on Particle Swarm Optimization and Simulated Annealing algorithms. (d) Incorporation of the priority constraint in the scheduling process by considering three priorities levels including the tasks, queues and VMs. Results: The results comparison of our algorithm with particle swarm optimization and First Come First Serve algorithms demonstrate the effectiveness of our algorithm in terms of waiting time, makespan, resources utilization and degree of imbalance. Conclusion: This study introduces an efficient strategy to schedule users’ tasks by using dynamic dispatch queues and particle swarm optimization with simulated annealing algorithms. Moreover, it incorporates the priority issue in the scheduling process.

Homomorphic encryption (HE) technique provides a third party with the ability to execute operations on ciphertexts. This property can be considered as a good solution to overcome some barriers limiting the widespread adoption of cloud services. However, since cloud environments are more threatened by security attacks and since cloud consumers often access to cloud services using resource-constrained devices, the HE schemes have to be promoted at security level and at running time to work efficiently. In El Makkaoui et al. (Cloud-RSA: an enhanced homomorphic encryption scheme. In: Rocha A, Serrhini M, Felgueiras C (eds) Europe and MENA cooperation advances in information and communication technologies. Advances in intelligent systems and computing, vol 520. Springer, Cham, pp 471–480, 2017b), we boosted RSA scheme at security level, Cloud-RSA. In this paper, we suggest two variants of Cloud-RSA scheme in order to speed up its decryption process. The variants are based on modifying the form of Cloud-RSA modulus and exponents. The first variant uses a modulus formed of two or more distinct primes and employs the Chinese remainder theorem (CRT) to encrypt and decrypt. Whereas, the second variant uses a modulus of the form n=prqsfor r≥2and s≥1, and applies the Hensel lifting and the CRT to decrypt. Theoretical and simulation results show that the proposed variants provide a large decryption speedup over Cloud-RSA.

Homomorphic encryption (HE) is an encryption form that offers a third-party with the ability to carry out computations on encrypted data. This property can be considered as a great solution to get over some obstacles limiting the wide-spread adoption of cloud computing (CC) services. Since CC environments are threatened by insider/outsider security attacks and since CC consumers often access to CC services using resource-limited devices, the HE schemes need to be promoted at security level and at running time to work effectively. For this reason, at EMENA-TSSL'16 and at WINCOM'16, the authors respectively boosted the RSA and ElGamal cryptosystems at security level, Cloud-RSA and Cloud-ElGamal. At SCAMS'17 and at EUSPN'17, the authors then suggested two fast variants of the Cloud-RSA scheme. All proposed schemes support the multiplicative homomorphism (MH) over the integers. The aim of this article is to compare the Cloud-ElGamal scheme with the Cloud-RSA schemes. This article first briefly presents the HE schemes and analyzes their security. This article then implements the schemes, compare and discuss their efficiency.

Concerns over data confidentiality are amongst the main barriers limiting the widespread adoption of cloud solutions. Indeed, scientists have invented a new promising form of encryption, homomorphic encryption (HE), which can be considered as a powerful tool to get over these concerns. Since cloud environments are more vulnerable to attacks and since cloud consumers frequently access to cloud computing services using light-weight devices, the HE schemes must be promoted, in terms of security level and running time, to operate efficiently. In El Makkaoui et al. (2017), we boosted the normal RSA cryptosystem at security level, cloud-RSA. In this paper, we suggest a new fast variant of the Cloud-RSA scheme, MultiPime cloud-RSA, to accelerate its decryption process. The variant uses a modulus of the form n= Πki=1pifor k≥ 2 and employs the Chinese remaindering to decrypt. Theoretical and simulation results show that the new variant offers a large decryption speed-up over the cloud-RSA scheme whilst maintaining a recommended security level.

Wireless Sensor Network (WSN) is consisting of independent and distributed sensors to monitor physical or environmental conditions, such as temperature, sound, pressure, etc. The most crucial and fundamental challenge facing WSN is security. Due to minimum capacity in-term of memory cost, processing and physical accessibility to sensors devices the security attacks are problematic. They are mostly deployed in open area, which expose them to different kinds of attacks. In this paper, the authors present an illustration of different attacks and vulnerabilities in WSN. Then the authors proposed a new lightweight cryptography algorithm for identifying compromised node in WSN called Leap Enhanced. Their evaluations on TOSSIM give a precise and detailed idea of the extra cost of consumption of resources needed to ensure the high level of expected security compared to other cryptography schemes in literature.

With the emergence of cloud computing, the concept of security has become a major issue. Indeed, the key challenge is to ensure customers that the selected cloud provider may store and process the sensitive data confidentially. If this is a storage service, data can be encrypted before sending them to the cloud server; in this case, data confidentiality is assured. However, before performing treatments, these data must be decrypted. It is this step that can be considered a breach of confidentiality. Indeed, the fear of seeing sensitive data be processed in raw is a major obstacle in adopting cloud services. To overcome this obstacle and strengthen confidence in the cloud services, in this paper we propose the adoption of homomorphic encryption technique which allows to perform operations on encrypted data without knowing the key secret.