Floating-point arithmetic is ubiquitous across computing, with its wide range of values, large and small, making it the preferred tool for storing, analysing, and manipulating numerical data. Its flexibility comes at the cost of additional risks in some security/privacy-aware settings. In this paper, we discuss the threat of information leakage caused by floating-point arithmetic when adding noise to sensitive values, which can allow the sensitive information to be recovered (e.g., in differential privacy). We present a solution, Mantissa Bit Manipulation (MBM), that is orders of magnitude faster than the current state-of-the-art, applicable to most continuous probability distributions and to all floating-point number formats.

Data protection algorithms are becoming increasingly important to support modern business needs for facilitating data sharing and data monetization. Anonymization is an important step before data sharing. Several organizations leverage on third parties for storing and managing data. However, third parties are often not trusted to store plaintext personal and sensitive data; data encryption is widely adopted to protect against intentional and unintentional attempts to read personal/sensitive data. Traditional encryption schemes do not support operations over the ciphertexts and thus anonymizing encrypted datasets is not feasible with current approaches. This paper explores the feasibility and depth of implementing a privacy-preserving data publishing workflow over encrypted datasets leveraging on homomorphic encryption. We demonstrate how we can achieve uniqueness discovery, data masking, differential privacy and k-anonymity over encrypted data requiring zero knowledge about the original values. We prove that the security protocols followed by our approach provide strong guarantees against inference attacks. Finally, we experimentally demonstrate the performance of our data publishing workflow components.

Person-specific data offer enormous opportunities for deriving insights that can radically improve different facets of our everyday lives, ranging from the provisioning of personalized medicine and healthcare, to the offering of smart transportation and smart energy. At the same time, the use of person-specific data to support these applications can come at a high cost to individuals' privacy, unless proper de-identification technology is in place to provide rigorous privacy guarantees. In this paper we introduce PRIMA, an end-to-end solution allowing decision makers to map out and execute their data privacy strategy through a comprehensive workflow. Our toolkit offers an intuitive risk-utility exploration framework for end users to navigate through the enormous number of possible combinations of anonymization settings and provide meaningful reports that help them understand the impact of each strategy in terms of utility and risk. Unlike traditional approaches, that rely on limited scale tools and manual analyses, our toolkit is the first scalable, production-grade system that can execute all of its components (such as vulnerability analysis, anonymization, risk and information loss measurements) on arbitrarily large datasets. Furthermore, it offers a flexible library for developers to integrate and extend its functionality to embed de-identification components into their applications.

We examine a generalised randomised response (RR) technique in the context of differential privacy and examine the optimality of such mechanisms. Strict and relaxed differential privacy are considered for binary outputs. By examining the error of a statistical estimator, we present closed solutions for the optimal mechanism(s) in both cases. The optimal mechanism is also given for the specific case of the original RR technique as introduced by Warner in 1965.