Handling Confidential Data on the Untrusted Cloud: An Agent-based Approach

Cloud computing allows shared computer and storage facilities to be used by a multitude of clients. While cloud management is centralized, the information resides in the cloud and information sharing can be implemented via off-the-shelf techniques for multiuser databases. Users, however, are very diffident for not having full control over their sensitive data. Untrusted database-as-a-server techniques are neither readily extendable to the cloud environment nor easily understandable by non-technical users. To solve this problem, we present an approach where agents share reserved data in a secure manner by the use of simple grant-and-revoke permissions on shared data.Comment: 7 pages, 9 figures, Cloud Computing 201

iPrivacy: a Distributed Approach to Privacy on the Cloud

The increasing adoption of Cloud storage poses a number of privacy issues. Users wish to preserve full control over their sensitive data and cannot accept that it to be accessible by the remote storage provider. Previous research was made on techniques to protect data stored on untrusted servers; however we argue that the cloud architecture presents a number of open issues. To handle them, we present an approach where confidential data is stored in a highly distributed database, partly located on the cloud and partly on the clients. Data is shared in a secure manner using a simple grant-and-revoke permission of shared data and we have developed a system test implementation, using an in-memory RDBMS with row-level data encryption for fine-grained data access controlComment: 13 pages, International Journal on Advances in Security 2011 vol.4 no 3 & 4. arXiv admin note: substantial text overlap with arXiv:1012.0759, arXiv:1109.355

iPrivacy : a distributed approach to privacy on the cloud

The increasing adoption of Cloud storage poses a number of privacy issues. Users wish to preserve full control over their sensitive data and cannot accept that it is accessible by the remote storage provider. Previous research was made on techniques to protect data stored on untrusted servers; however we argue that the cloud architecture presents a number of open issues. To handle them, we present an approach where confidential data is stored in a highly distributed database, partly located on the cloud and partly on the clients. Data is shared in a secure manner using a simple grant-and-revoke permission of shared data and we have developed a system test implementation, using an in memory Relational Data Base Management System with row-level data encryption for fine-grained data access control

Key Indistinguishability vs. Strong Key Indistinguishability for Hierarchical Key Assignment Schemes

A hierarchical key assignment scheme is a method to assign some private information and encryption keys to a set of classes in a partially ordered hierarchy, in such a way that the private information of a higher class can be used to derive the keys of all classes lower down in the hierarchy. In this paper we analyze the security of hierarchical key assignment schemes according to different notions: security with respect to key indistinguishability and against key recovery, as well as the two recently proposed notions of security with respect to strong key indistinguishability and against strong key recovery. We first explore the relations between all security notions and, in particular, we prove that security with respect to strong key indistinguishability is not stronger than the one with respect to key indistinguishability. Afterwards, we propose a general construction yielding a hierarchical key assignment scheme offering security against strong key recovery, given any hierarchical key assignment scheme which guarantees security against key recovery

New Constructions for Provably-Secure Time-Bound Hierarchical Key Assignment Schemes

A time-bound hierarchical key assignment scheme is a method to assign time-dependent encryption keys to a set of classes in a partially ordered hierarchy, in such a way that each class in the hierarchy can compute the keys of all classes lower down in the hierarchy, according to temporal constraints. In this paper we propose new constructions for time-bound hierarchical key assignment schemes which are provably secure with respect to key indistinguishability.\ud Our constructions use as a building block any provably-secure hierarchical key assignment scheme without temporal constraints and exhibit a tradeoff among the amount of private information held by each class, the amount of public data, the complexity of key derivation, and the computational assumption on which their security is based. Moreover, the proposed schemes support updates to the access hierarchy with local changes to public information and without requiring any private information to be re-distributed

New Constructions for Provably-Secure Time-Bound Hierarchical Key Assignment Schemes

Abstract A time-bound hierarchical key assignment scheme is a method to assign time-dependentencryption keys to a set of classes in a partially ordered hierarchy, in such a way that each class in the hierarchy can compute the keys of all classes lower down in the hierarchy, according totemporal constraints. In this paper we propose new constructions for time-bound hierarchical key assignmentschemes which are provably secure with respect to key indistinguishability. Our constructions use as a building block any provably-secure hierarchical key assignment scheme without temporalconstraints and exhibit a tradeoff among the amount of private information held by each class, the amount of public data, the complexity of key derivation, and the computational assumptionon which their security is based. Moreover, the proposed schemes support updates to the access hierarchy with local changes to the public information and without requiring any privateinformation to be re-distributed. Keywords: Access control, key assignment, provable security, efficient key derivation. 1 Introduction Users of a computer system could be organized in a hierarchy formed by a certain number of disjoint classes. These classes, called security classes, are positioned and ordered within the hierarchy based on the fact that some users have more access rights than others. For example, within a hospital system, doctors can access all data concerning their patients, whereas, researchers can be limited to consult anonymous clinical information for studies. Similar cases abound in other areas, particularly in the government and military