An Application of Partial Homomorphic Encryption in Computer System with Limited Resources

Mathematical calculation over ciphertext during homomorphic encryption makes result of the calculation in a form of ciphertext. Obtained result can be decrypted with an appropriate key for further usage. In the era of cloud computing, this feature can be used to solve problems of storing and processing sensitive data in the cloud. Also, use of homomorphic encryption keeps both, data and results of processing, highly secured at the same time. Considering the overwhelming presence of computers with limited resources, the presence of the Internet and the ultimate practical need for use of cloud and its resources, in this paper we explored and presented the characteristics of a practical use of partial homomorphic encryption and its processing of ciphertext in the cloud on computer system with limited resources

k-Nearest Neighbor Classification over Semantically Secure Encrypted Relational Data

Data Mining has wide applications in many areas such as banking, medicine, scientific research and among government agencies. Classification is one of the commonly used tasks in data mining applications. For the past decade, due to the rise of various privacy issues, many theoretical and practical solutions to the classification problem have been proposed under different security models. However, with the recent popularity of cloud computing, users now have the opportunity to outsource their data, in encrypted form, as well as the data mining tasks to the cloud. Since the data on the cloud is in encrypted form, existing privacy preserving classification techniques are not applicable. In this paper, we focus on solving the classification problem over encrypted data. In particular, we propose a secure k-NN classifier over encrypted data in the cloud. The proposed k-NN protocol protects the confidentiality of the data, user's input query, and data access patterns. To the best of our knowledge, our work is the first to develop a secure k-NN classifier over encrypted data under the semi-honest model. Also, we empirically analyze the efficiency of our solution through various experiments.Comment: 29 pages, 2 figures, 3 tables arXiv admin note: substantial text overlap with arXiv:1307.482

Recent Advances in Σ-definability over Continuous Data Types

The purpose of this paper is to survey our recent research in computability and definability over continuous data types such as the real numbers, real-valued functions and functionals. We investigate the expressive power and algorithmic properties of the language of Sigma-formulas intended to represent computability over the real numbers. In order to adequately represent computability we extend the reals by the structure of hereditarily finite sets. In this setting it is crucial to consider the real numbers without equality since the equality test is undecidable over the reals. We prove Engeler's Lemma for Sigma-definability over the reals without the equality test which relates Sigma-definability with definability in the constructive infinitary language L_{omega_1 omega}. Thus, a relation over the real numbers is Sigma-definable if and only if it is definable by a disjunction of a recursively enumerable set of quantifier free formulas. This result reveals computational aspects of Sigma-definability and also gives topological characterisation of Sigma-definable relations over the reals without the equality test. We also illustrate how computability over the real numbers can be expressed in the language of Sigma-formulas

A Simpler Rate-Optimal CPIR Protocol

In PETS 2015, Kiayias, Leonardos, Lipmaa, Pavlyk, and Tang proposed the first $(n, 1)$-CPIR protocol with rate $1 - o (1)$. They use advanced techniques from multivariable calculus (like the Newton-Puiseux algorithm) to establish optimal rate among a large family of different CPIR protocols. It is only natural to ask whether one can achieve similar rate but with a much simpler analysis. We propose parameters to the earlier $(n, 1)$-CPIR protocol of Lipmaa (ISC 2005), obtaining a CPIR protocol that is asymptotically almost as communication-efficient as the protocol of Kiayias et al. However, for many relevant parameter choices, it is slightly more communication-efficient, due to the cumulative rounding errors present in the protocol of Kiayias et al. Moreover, the new CPIR protocol is simpler to understand, implement, and analyze. The new CPIR protocol can be used to implement (computationally inefficient) FHE with rate $1 - o (1)$

Hierarchical and dynamic threshold Paillier cryptosystem without trusted dealer

We propose the first hierarchical and dynamic threshold Paillier cryptosystem without trusted dealer and prove its security in the malicious adversary model. The new cryptosystem is fully distributed, i. e., public and private key generation is performed without a trusted dealer. The private key is shared with a hierarchical and dynamic secret sharing scheme over the integers. In such a scheme not only the amount of shareholders, but also their levels in the hierarchy decide whether or not they can reconstruct the secret and new shareholders can be added or removed without reconstruction of the secret

Criptografía en bases de datos en cloud computing.

The IT managers of companies who are considering migrating their systems to the cloud computing have their reservationsabout the security and reliability of cloud-based services, these are not yet fully convinced that deliver sensitive data companies or theirclients is a good idea, in this context the use of encryption systems, in particular homomorphic encryption schemes are useful, since theoperations in the cloud provider are made with the encrypted information, providing a level of reliability and safety databases fromattacks as well as internal and external in cloud computing. This paper proposes a scheme to protect the different attributes ofinformation (confidentiality, integrity and authentication), stored in a BD in the Cloud.Los responsables de informática de las empresas que están pensando migrar sus sistemas de cómputo a la nube tienensus reservas con respecto a la seguridad y la confiabilidad de los servicios basados en la nube, éstos aún no están plenamenteconvencidos de que entregar datos sensibles de las empresas o de sus clientes sea buena idea, en este contexto el uso de los sistemas decifrado, y en especial los esquemas de cifrado homomórficos son de gran utilidad, ya que las operaciones realizadas en el proveedorcloud se realizan con la información cifrada, brindando así un nivel de confiabilidad y seguridad a las bases de datos frente a posiblesataques tanto internos como externos en el cloud computing. En el presente trabajo se propone un esquema para proteger los diferentesatributos de la información (confidencialidad, integridad y autenticación) almacenada en una BD en el Cloud