Juha Partala

Security threats against the transmission chain of a medical health monitoring system

One of the most important aspects of a wireless health monitoring system is the security of data. In this paper, security attacks against the complete transmission chain of a medical health monitoring system are enumerated and classified based on their threat to three security principles: confidentiality, integrity and availability. The communication chain is divided in a standard way into three tiers and relevant threats are identified for each tier. Security requirements corresponding to these threats are presented. It is noted that end-to-end security is not feasible due to distributed computing and the incompatibility of the data standards of different tiers.

A data hiding approach for sensitive smartphone data

We develop and evaluate a data hiding method that enables smartphones to encrypt and embed sensitive information into carrier streams of sensor data. Our evaluation considers multiple handsets and a variety of data types, and we demonstrate that our method has a computational cost that allows real-time data hiding on smartphones with negligible distortion of the carrier stream. These characteristics make it suitable for smartphone applications involving privacy-sensitive data such as medical monitoring systems and digital forensics tools.

IEEE802.15.6 -based multi-accelerometer WBAN system for monitoring Parkinson's disease

In this paper we present a detailed example of a wireless body area network (WBAN) scenario utilizing the recent IEEE802.15.6 standard as applied to a multi-accelerometer system for monitoring Parkinsons disease and fall detection. Ultra wideband physical layer and standard security protocols are applied to meet application requirements for data rate and security.

Receiver performance evaluation on IEEE 802.15.6 based WBAN for monitoring Parkinson's disease

Advantages of remote health monitoring are incontestable: prolonging the patients possibility to stay at home by monitoring the health condition remotely, the quality of patients life is improved as well as healthcare costs are significantly reduced. Parkinsons disease is one example, for which some wireless monitoring systems have been presented recently. However, concrete performance evaluations for the IEEE 802.15.6 standard based communication in the realistic use scenarios have not been presented yet in the literature. The aim of this paper is to evaluate performance of ultra wideband energy detector receivers on the physical layer of the IEEE 802.15.6 standard. The monitoring system and node locations are designed for monitoring Parkinsons disease symptoms. Measurement based radio channel models were used in the evaluations. Two modulation methods, on-off keying and pulse position modulation, are evaluated and compared using two different antennas suitable for body area network communication. Pulse position modulation based system is found to outperform on-off keying based system, which on the other hand, is simpler to implement. Furthermore, it is shown how antenna placement, position, and properties are impacting on the channel characteristics of the radio link, and hence, on the bit error rate performance.

On enabling techniques for personal audio content management

State-of-the-art automatic analysis tools for personal audio con-tent management are discussed in this paper. Our main target is to create a system, which has several co-operating management tools for audio database and which improve the results of each other. Bayesian networks based audio classification algorithm provides classification into four main audio classes (silence, speech, music, and noise) and serves as a first step for other subsequent analysis tools. For speech analysis we propose an improved Bayesian information criterion based speaker segmen-tation and clustering algorithm applying also a combined gender and emotion detection algorithm utilizing prosodic features. For the other main classes it is often hard to device any general and well functional pre-categorization that would fit the unforesee-able types of user recorded data. For compensating the absence of analysis tools for these classes we propose the use of efficient audio similarity measure and query-by-example algorithm with database clustering capabilities. The experimental results show that the combined use of the algorithms is feasible in practice.

On the conjugacy search problem and left conjugacy closed loops

The conjugacy search problem (CSP) is used as a primitive in several braid group-based public key encryption schemes. It has been pointed out that, in braid groups, it is unlikely to provide adequate security. Therefore, new structures need to be found. In this paper, we give a formulation of the CSP for left conjugacy closed loops. In order to construct a generalization of the Anshel–Anshel–Goldfeld key establishment method, we also define a partial conjugacy search problem PCSP and show it to be equivalent to the CSP, if the underlying structure is a group. We also study more closely the PCSP in a class of conjugacy closed loops of order p2, where p is a prime.

Provably Secure Covert Communication on Blockchain

Blockchain is a public open ledger that provides data integrity in a distributed manner. It is the underlying technology of cryptocurrencies and an increasing number of related applications, such as smart contracts. The open nature of blockchain together with strong integrity guarantees on the stored data makes it a compelling platform for covert communication. In this paper, we suggest a method of securely embedding covert messages into a blockchain. We formulate a simplified ideal blockchain model based on existing implementations and devise a protocol that enables two parties to covertly communicate through the blockchain following that model. We also formulate a rigorous definition for the security and covertness of such a protocol based on computational indistinguishability. Finally, we show that our method satisfies this definition in the random oracle model for the underlying cryptographic hash function.

Defining an architecture for evolving environments

The architecture of a system specifies how the system should be designed and built. However, shortcomings are identified in current architecture process frameworks concerning evolving domains like healthcare. We claim that an iterative architecture process is required, where the technical concerns are separated from the non-technical ones. Furthermore, a strong guiding vision is required. Based on our experiences from a biobank IT infrastructure process, we present an architecture process that is modular, interoperable, controlled and abstracted, thus being capable of handling complex systems with large uncertainties.

Semantically Secure Symmetric Encryption with Error Correction for Distributed Storage

A distributed storage system (DSS) is a fundamental building block in many distributed applications. It applies linear network coding to achieve an optimal tradeoff between storage and repair bandwidth when node failures occur. Additively homomorphic encryption is compatible with linear network coding. The homomorphic property ensures that a linear combination of ciphertext messages decrypts to the same linear combination of the corresponding plaintext messages. In this paper, we construct a linearly homomorphic symmetric encryption scheme that is designed for a DSS. Our proposal provides simultaneous encryption and error correction by applying linear error correcting codes. We show its IND-CPA security for a limited number of messages based on binary Goppa codes and the following assumption: when dividing a scrambled generator matrix into two parts and , it is infeasible to distinguish from random and to find a statistical connection between and . Our infeasibility assumptions are closely related to those underlying the McEliece public key cryptosystem but are considerably weaker. We believe that the proposed problem has independent cryptographic interest.

Symmetric Blind Decryption with Perfect Secrecy

A blind decryption scheme enables a user to query decryptions from a decryption server without revealing information about the plaintext message. Such schemes are useful, for example, for the implementation of privacy preserving encrypted file storages and payment systems. In terms of functionality, blind decryption is close to oblivious transfer. For noiseless channels, information-theoretically secure oblivious transfer is impossible. However, in this paper we show that this is not the case for blind decryption. We formulate a definition of perfect secrecy of symmetric blind decryption for the following setting: at most one of the scheme participants is a malicious observer. We also devise a symmetric blind decryption scheme based on modular arithmetic on a ring