The distributed nature and dynamic topology of Wireless Sensor Networks (WSNs) introduces very special requirements in routing protocols that should be met. The most important feature of a routing protocol, in order to be efficient for WSNs, is the energy consumption and the extension of the network's lifetime. During the recent years, many energy efficient routing protocols have been proposed for WSNs. In this paper, energy efficient routing protocols are classified into four main schemes: Network Structure, Communication Model, Topology Based and Reliable Routing. The routing protocols belonging to the first category can be further classified as flat or hierarchical. The routing protocols belonging to the second category can be further classified as Query-based or Coherent and non-coherent-based or Negotiation-based. The routing protocols belonging to the third category can be further classified as Location-based or Mobile Agent-based. The routing protocols belonging to the fourth category can be further classified as QoS-based or Multipath-based. Then, an analytical survey on energy efficient routing protocols for WSNs is provided. In this paper, the classification initially proposed by Al-Karaki, is expanded, in order to enhance all the proposed papers since 2004 and to better describe which issues/operations in each protocol illustrate/enhance the energy-efficiency issues.

Energy-Efficient Routing Protocols in Wireless Sensor Networks: A Survey

Cryptosystems I.- On Ideal Lattices and Learning with Errors over Rings.- Fully Homomorphic Encryption over the Integers.- Converting Pairing-Based Cryptosystems from Composite-Order Groups to Prime-Order Groups.- Fully Secure Functional Encryption: Attribute-Based Encryption and (Hierarchical) Inner Product Encryption.- Obfuscation and Side Channel Security.- Secure Obfuscation for Encrypted Signatures.- Public-Key Encryption in the Bounded-Retrieval Model.- Protecting Circuits from Leakage: the Computationally-Bounded and Noisy Cases.- 2-Party Protocols.- Partial Fairness in Secure Two-Party Computation.- Secure Message Transmission with Small Public Discussion.- On the Impossibility of Three-Move Blind Signature Schemes.- Efficient Device-Independent Quantum Key Distribution.- Cryptanalysis.- New Generic Algorithms for Hard Knapsacks.- Lattice Enumeration Using Extreme Pruning.- Algebraic Cryptanalysis of McEliece Variants with Compact Keys.- Key Recovery Attacks of Practical Complexity on AES-256 Variants with up to 10 Rounds.- IACR Distinguished Lecture.- Cryptography between Wonderland and Underland.- Automated Tools and Formal Methods.- Automatic Search for Related-Key Differential Characteristics in Byte-Oriented Block Ciphers: Application to AES, Camellia, Khazad and Others.- Plaintext-Dependent Decryption: A Formal Security Treatment of SSH-CTR.- Computational Soundness, Co-induction, and Encryption Cycles.- Models and Proofs.- Encryption Schemes Secure against Chosen-Ciphertext Selective Opening Attacks.- Cryptographic Agility and Its Relation to Circular Encryption.- Bounded Key-Dependent Message Security.- Multiparty Protocols.- Perfectly Secure Multiparty Computation and the Computational Overhead of Cryptography.- Adaptively Secure Broadcast.- Universally Composable Quantum Multi-party Computation.- Cryptosystems II.- A Simple BGN-Type Cryptosystem from LWE.- Bonsai Trees, or How to Delegate a Lattice Basis.- Efficient Lattice (H)IBE in the Standard Model.- Hash and MAC.- Multi-property-preserving Domain Extension Using Polynomial-Based Modes of Operation.- Stam's Collision Resistance Conjecture.- Universal One-Way Hash Functions via Inaccessible Entropy.- Foundational Primitives.- Constant-Round Non-malleable Commitments from Sub-exponential One-Way Functions.- Constructing Verifiable Random Functions with Large Input Spaces.- Adaptive Trapdoor Functions and Chosen-Ciphertext Security.

Advances in cryptology -- EUROCRYPT 2010 : 29th Annual International Conference on the Theory and Applications of Cryptographic Techniques, French Riviera, May 30-June 3, 2010 : proceedings

Cities are growing steadily, and the process of urbanization is a common trend in the world. Although cities are getting bigger, they are not necessarily getting better. With the aim to provide citizens with a better place to live, a new concept of a city was born: the smart city. The real meaning of smart city is not strictly defined, but it has gained much attention, and many cities are taking action in order to be considered 'smart'. These smart cities, founded on the use of information and communication technologies, aim at tackling many local problems, from local economy and transportation to quality of life and e-governance. Although technology helps to solve many of these local problems, their ability to gather unprecedented amounts of information could endanger the privacy of citizens. In this article we identify a number of privacy breaches that can appear within the context of smart cities and their services. We leverage some concepts of previously defined privacy models and define the concept of citizens' privacy as a model with five dimensions: identity privacy, query privacy, location privacy, footprint privacy and owner privacy. By means of several examples of smart city services, we define each privacy dimension and show how existing privacy enhancing technologies could be used to preserve citizens' privacy.

The pursuit of citizens' privacy: a privacy-aware smart city is possible

This is an implementation of the Data Encryption Standard (DES) for the open-source computer software system, Sage. This only allows the encryption of a single 64-bit plaintext with a 64-bit key. It thus provides a foundation for the user to build up triple-DES, DES in standard NIST block modes (ECB, CBC etc), and for padding. None of these are provided in this implementation.

Data Encryption Standard (DES) for Sage

Private information retrieval (PIR) is a key building block in many privacy-preserving systems. Unfortunately, existing constructions remain very expensive. This paper introduces two techniques that make the computational variant of PIR (CPIR) more efficient in practice. The first technique targets a recent class of CPU-efficient CPIR protocols where the query sent by the client contains a number of ciphertexts proportional to the size of the database. We show how to compresses this query, achieving size reductions of up to 274X. The second technique is a new data encoding called probabilistic batch codes (PBCs). We use PBCs to build a multi query PIR scheme that allows the server to amortize its computational cost when processing a batch of requests from the same client. This technique achieves up to 40× speedup over processing queries one at a time, and is significantly more efficient than related encodings. We apply our techniques to the Pung private communication system, which relies on a custom multi-query CPIR protocol for its privacy guarantees. By porting our techniques to Pung, we find that we can simultaneously reduce network costs by 36× and increase throughput by 3X.

/pdf/pir-with-compressed-queries-and-amortized-query-processing-bzqbzwyui8.pdf

PIR with Compressed Queries and Amortized Query Processing

Private Information Retrieval (PIR) allows a user to retrieve the ith bit of an n-bit database without revealing to the database server the value of i. In this paper, we present a PIR protocol with the communication complexity of O(γ logn) bits, where -y is the ciphertext size. Furthermore, we extend the PIR protocol to a private block retrieval (PBR) protocol, a natural and more practical extension of PIR in which the user retrieves a block of bits, instead of retrieving single bit. Our protocols are built on the state-of-the-art fully homomorphic encryption (FHE) techniques and provide privacy for the user if the underlying FHE scheme is semantically secure. The total communication complexity of our PBR is O(γ logm + γn/m) bits, where m is the number of blocks. The total computation complexity of our PBR is O(m logm) modular multiplications plus O(n=2) modular additions. In terms of total protocol execution time, our PBR protocol is more efficient than existing PBR protocols which usually require to compute O(n=2) modular multiplications when the size of a block in the database is large and a high-speed network is available.

Single-Database Private Information Retrieval from Fully Homomorphic Encryption

Association rule mining (ARM) is one of the popular data mining methods that discover interesting correlations amongst a large collection of data, which appears incomprehensible. This is known to be a trivial task when the data is owned by one party. But when multiple data sites collectively engage in ARM, privacy concerns are introduced. Due to this concern, privacy preserving data mining algorithms have been developed to attain the desired result, while maintaining privacy. In the case of two party privacy preserving ARM for horizontally partitioned databases, both parties are required to compare their itemset counts securely. This problem is comparable to the famous millionaire problem of Yao. However, in this paper, we propose a secure comparison technique using fully homomorphic encryption scheme that provides a similar level of security to the Yao based solution, but promotes greater efficiency due to the reuse of resources.

Fully homomorphic encryption based two-party association rule mining

Wireless sensor networks (WSNs) are prone to vulnerabilities due to their resource constraints and deployment in remote and unattended areas. A sensor node exhibits anomaly in behaviour due to its dying energy level or being compromised by the intruders. The node showing anomalous behaviours being a leader node (LN) of a cluster/group multifolds the vulnerability problem. To identify the anomalous nodes in WSNs, this paper presents a model, which uses a Voronoi diagram based network architecture. The network architecture, which deploys mobile data collectors (MDCs), ensures the compatibility of the anomaly detection model for the resource constrained WSNs, and warrants data integrity between the MDCs and the LNs. Our empirical evidence shows the effectiveness of the proposed approach.

Anomaly Detection in Wireless Sensor Network

The electronic health record (eHR) system has recently been considered one of the biggest advancements in healthcare services. A personally controlled electronic health record (PCEHR) system is proposed by the Australian government to make the health system more agile, secure, and sustainable. Although the PCEHR system claims the electronic health records can be controlled by the patients, healthcare professionals and database/system operators may assist in disclosing the patients’ eHRs for retaliation or other ill purposes. As the conventional methods for preserving the privacy of eHRs solely trust the system operators, these data are vulnerable to be exploited by the authorised personnel in an immoral/unethical way. Furthermore, issues such as the sheer number of eHRs, their sensitive nature, flexible access, and efficient user revocation have remained the most important challenges towards fine-grained, cryptographically enforced data access control. In this paper we propose a patient centric cloud-based PCEHR framework, which employs a homomorphic encryption technique in storing the eHRs. The proposed system ensures the control of both access and privacy of eHRs stored in the cloud database.

/pdf/a-privacy-preserving-framework-for-personally-controlled-vhtfaq3mxm.pdf

A Privacy-Preserving Framework for Personally Controlled Electronic Health Record (PCEHR) System

Concealing a message and ensuring its security is inevitable in data transmission. Among various concepts, one approach is steganography that encodes secret message in indiscernible way. In this paper, we present an audio steganographic technique and propose a novel approach to hide data in the least significant bit (LSB) of the stereo-audio samples with CD-quality. Here, on the basis of stego-key and its parity, message bits are encoded into cover audio samples. In terms of security and imperceptibility, this method is a significant improvement of LSB method for hiding information in audio.

Mohammed Kaosar

Papers

Single-Database Private Information Retrieval from Fully Homomorphic Encryption

Fully homomorphic encryption based two-party association rule mining

Anomaly Detection in Wireless Sensor Network

A Privacy-Preserving Framework for Personally Controlled Electronic Health Record (PCEHR) System

An approach for enhancing message security in audio steganography