SECRYPT 2017 Abstracts


Full Papers
Paper Nr: 1
Title:

Freeze & Crypt: Linux Kernel Support for Main Memory Encryption

Authors:

Manuel Huber, Julian Horsch, Junaid Ali and Sascha Wessel

Abstract: We present Freeze & Crypt, a framework for RAM encryption. Our goal is to protect the sensitive data the processes keep in RAM against memory attacks, such as coldboot, DMA, or JTAG attacks. This goal is of special significance when it comes to protect unattended or stolen devices, such as smartphones, tablets and laptops, against physical attackers. Freeze & Crypt makes use of the kernel’s freezer, which allows freezing a group of processes by holding them firm in the so-called refrigerator. Inside, frozen processes inescapably rest at a point in kernel space where they cannot access their memory from user space. We extend the freezer to make arbitrary process groups transparently and dynamically encrypt their full memory space with a key only present during en- and decryption. When thawing a process group, each process decrypts its memory space, leaves the refrigerator and resumes normal execution. We develop a prototype and deploy it onto productively used mobile devices running Android containers. With this application scenario, we show how our mechanism protects the sensitive data in RAM against physical attackers when a container or device is not in active use.

Paper Nr: 10
Title:

A Lightweight Integrity Protection Scheme for Fast Communications in Smart Grid

Authors:

Alireza Jolfaei and Krishna Kant

Abstract: Due to the mission-critical nature of energy management, smart power grids are prime targets for cyber-attacks. A key security objective in the smart grid is to protect the integrity of synchronized real-time measurements taken by phasor measurement units (PMUs). The current communication protocol in substation automation allows the transmission of PMU data in absence of integrity protection for applications that strictly require low communication latency. This leaves the PMU data vulnerable to man-in-the-middle attacks. In this paper, a lightweight and secure integrity protection algorithm has been proposed to maintain the integrity of PMU data, which fills the missing integrity protection in the IEC 61850-90-5 standard, when the MAC identifier is declared 0. The rigorous security analysis proves the security of the proposed integrity protection method against ciphertext-only attacks and known/chosen plaintext attacks. A comparison with existing integrity protection methods shows that our method is much faster, and is also the only integrity protection scheme that meets the strict timing requirement. Not only the proposed method can be used in power protection applications, but it also can be used in emerging anomaly detection scenarios, where a fast integrity check coupled with low latency communications is used for multiple rounds of message exchanges.

Paper Nr: 12
Title:

Forensic Analysis of Communication Records of Web-based Messaging Applications from Physical Memory

Authors:

Diogo Barradas, Tiago Brito, David Duarte, Nuno Santos and Luís Rodrigues

Abstract: Inspection of physical memory allows digital investigators to retrieve evidence otherwise inaccessible when analyzing other storage media. In this paper, we analyze in-memory communication records produced by web-based instant messaging and email applications. Our results show that, in spite of the heterogeneity of data formats specific to each application, communication records can be represented in a common application-independent format. This format can then be used as a common representation to allow for general analysis of digital artifacts across various applications, even when executed in different browsers. Then, we introduce RAMAS, an extensible forensic tool which aims to ease the process of analyzing communication records left behind in physical memory by instant-messaging and email web clients.

Paper Nr: 14
Title:

Formally Verifying Flow Properties in Industrial Systems

Authors:

Jannik Dreier, Maxime Puys, Marie-Laure Potet, Pascal Lafourcade and Jean-Louis Roch

Abstract: In contrast to other IT systems, industrial systems often do not only require classical properties like data confidentiality or authentication of the communication, but have special needs due to their interaction with physical world. For example, the reordering or deletion of some commands sent to a machine can cause the system to enter an unsafe state with potentially catastrophic effects. To prevent such attacks, the integrity of the message flow is necessary. We provide a formal definition of Flow Integrity. We apply our framework to two well-known industrial protocols: OPC-UA and MODBUS. Using TAMARIN, a cryptographic protocol verification tool, we confirm that most of the secure modes of these protocols ensure Flow Integrity given a resilient network. However, we also identify a weakness in a supposedly secure version of MODBUS.

Paper Nr: 41
Title:

Attribute based Encryption for Multi-level Access Control Policies

Authors:

Nesrine Kaaniche and Maryline Laurent

Abstract: The economy and security of modern society relies on increasingly remote and distributed infrastructures. This trend increases both the complexity of access control to outsourced data and the need of privacy-preserving mechanisms. Indeed, access control policies should be flexible and distinguishable among users with different privileges. Also, privacy preservation should be ensured against curious storage system administrators, for outsourced data, as well as access requestors identities if needed. In this paper, we propose a multi-level access control mechanism based on an original use of attribute based encryption schemes. Our construction has several advantages. First, it ensures fine-grained access control, supporting multi-security levels with respect to different granted access rights for each outsourced data file. Second, relying on an attribute based mechanism, key management is minimized, such that users sharing the same access rights are not required to collaborate to extract the secret enciphering key. Third, our proposal is proven to provide efficient processing and communication overhead, compared to classical usage of attribute based encryption schemes.

Paper Nr: 46
Title:

Mobile Silent and Continuous Authentication using Apps Sequence

Authors:

Gerardo Canfora, Giovanni Cappabianca, Pasquale Carangelo, Fabio Martinelli, Francesco Mercaldo, Ernesto Rosario Russo and Corrado Aaron Visaggio

Abstract: The last years have seen a growing explosion of the use of mobile devices. As matter of fact “smart” devices are used for a plethora of activities: from spending leisure time on social networks to e-banking. For these reasons smart devices hold huge volumes of private and sensitive user data and allow the access to critical applications in terms of privacy and security. Currently mobile devices provide an authentication mechanism based on the login: they do not continuously verify the identity of the user while sensitive activities are performed. This mechanism may allow an adversary to access sensitive information about users and to replace them during sensitive tasks, once they have obtained the user’s credentials. To mitigate this risk, in this paper we propose a method for the silent and continuous authentication. Considering that each user typically runs recurrently a certain set of applications in every-day life, our method extracts this characterizing sequences of apps for profiling the user and recognizing the user of the device that is not the owner. Using machine learning techniques several classifiers have been trained and the effectiveness of the proposed method has been evaluated by modeling the user behavior of 15 volunteer participants. Encouraging results have been obtained, i.e. a precision in distinguishing an impostor from the owner equal to 99%. The main benefit of this method is that is does not use sensitive data, nor biometrics, which, if compromised, cannot be replaced.

Paper Nr: 49
Title:

The Efficient Randomness Testing using Boolean Functions

Authors:

Marek Sýs, Dušan Klinec and Petr Švenda

Abstract: The wide range of security applications requires data either truly random or indistinguishable from random. The statistical tests included in batteries such as NIST STS or Dieharder are frequently used to assess the randomness property. We designed a principally simple, yet powerful, statistical randomness test working on bit level. It is based on a search for boolean function(s) indicating a bias when applied to the tested stream not expected for truly random data. The deviances are detected in seconds rather than tens of minutes required by the common batteries. Importantly, the boolean function indicating the bias directly describes the pattern responsible for this bias. This allows to construct the bit predictor or to fix the cause of bias in the function design. The present bias is typically detected in at least an order of magnitude less data than required by NIST STS or Dieharder. The tests included in these batteries are either too simple to spot the common biases (like the Monobit test) or overly complex (like the Fourier Transform test) requiring an extensive amount of data. The proposed approach called BoolTest fills this gap. The performance was verified on more than 20 real world cryptographic functions – block and stream ciphers, hash functions and pseudorandom generators. Among others, the previously unknown bias in the output of C rand() and Java Random generators was found.

Paper Nr: 51
Title:

First Practical Side-channel Attack to Defeat Point Randomization in Secure Implementations of Pairing-based Cryptography

Authors:

Damien Jauvart, Jacques J. A. Fournier and Louis Goubin

Abstract: The field of Pairing Based Cryptography (PBC) has seen recent advances in the simplification of their calculations and in the implementation of original protocols for security and privacy. Like most cryptographic algorithms, PBC implementations on embedded devices are exposed to physical attacks such as side channel attacks, which have been shown to recover the secret points used in some PBC-based schemes. Various countermeasures have consequently been proposed. The present paper provides an updated review of the state of the art countermeasures against side channel attacks that target PBC implementations. We especially focus on a technique based on point blinding/randomization. We propose a collision based side-channel attack against an implementation embedding the point randomization countermeasure. It is, to the best of our knowledge, the first proposed attack against this countermeasure used in the PBC context and this raises questions about the validation of countermeasures for complex cryptographic schemes such as PBC. We also discuss about ways of thwarting our attack.

Paper Nr: 54
Title:

Analysis of Intrusion Detection Systems in Industrial Ecosystems

Authors:

Juan Enrique Rubio, Cristina Alcaraz, Rodrigo Roman and Javier Lopez

Abstract: For an effective protection of all the elements of an industrial ecosystem against threats, it is necessary to understand the true scope of existing mechanisms capable of detecting potential anomalies and intrusions. It is the aim of this article to review the threats that affect existing and novel elements of this ecosystem; and to analyze the state, evolution and applicability of both academic and industrial intrusion detection mechanisms in this field.

Paper Nr: 56
Title:

Face Recognition-based Presentation Attack Detection in a Two-step Segregated Automated Border Control e-Gate - Results of a Pilot Experience at Adolfo Suárez Madrid-Barajas Airport

Authors:

David Ortega del Campo, Cristina Conde, Ángel Serrano, Isaac Martín de Diego and Enrique Cabello

Abstract: This paper presents the pilot of a new Automatic Border Control system (ABC) that is being developed in the ABC4EU European project and that conform to the new laws established for the Schengen zone. These new ABCs have some specific characteristics, such as a structural configuration divided into two devices: self-enrolment kiosk and biometric gate, one for enrolment and the other one for verification, which entails two capture stages and two weaknesses where it is possible to attack the system. The tests were carried out with a pilot of the system, implemented at T4-S (T4 satellite) terminal of Adolfo Suárez Madrid-Barajas Airport. Our experiments have tested the security of the system by simulating several presentation attacks, at both stages of the system. For these attacks, different artefacts proposed in the literature about Presentation Attack Detection have been used. We present the obtained results with each of the attacks, indicating which may be more dangerous to the system and suggesting some countermeasure that could increase the reliability and security of the system.

Paper Nr: 60
Title:

Privacy-Preserving Verifiability - A Case for an Electronic Exam Protocol

Authors:

Rosario Giustolisi, Vincenzo Iovino and Gabriele Lenzini

Abstract: We introduce the notion of privacy-preserving verifiability for security protocols. It holds when a protocol admits a verifiability test that does not reveal, to the verifier that runs it, more pieces of information about the protocol’s execution than those required to run the test. Our definition of privacy-preserving verifiability is general and applies to cryptographic protocols as well as to human security protocols. In this paper we exemplify it in the domain of e-exams. We prove that the notion is meaningful by studying an existing exam protocol that is verifiable but whose verifiability tests are not privacy-preserving. We prove that the notion is applicable: we review the protocol using functional encryption so that it admits a verifiability test that preserves privacy according to our definition. We analyse, in ProVerif, that the verifiability holds despite malicious parties and that the new protocol maintains all the security properties of the original protocol, so proving that our privacy-preserving verifiability can be achieved starting from existing security.

Paper Nr: 62
Title:

On the Relation Between SIM and IND-RoR Security Models for PAKEs

Authors:

José Becerra, Vincenzo Iovino, Dimiter Ostrev and Marjan Škrobot

Abstract: Password-based Authenticated Key-Exchange (PAKE) protocols allow users, who need only to share a password, to compute a high-entropy shared session key despite passwords being taken from a dictionary. Security models for PAKE protocols aim to capture the desired security properties that such protocols must satisfy when executed in the presence of an active adversary. They are usually classified into i) indistinguishabilitybased (IND-based) or ii) simulation-based (SIM-based). The relation between these two security notions is unclear and mentioned as a gap in the literature. In this work, we prove that SIM-BMP security from Boyko et al. (EUROCRYPT 2000) implies IND-RoR security from Abdalla et al. (PKC 2005) and that IND-RoR security is equivalent to a slightly modified version of SIM-BMP security. We also investigate whether IND-RoR security implies (unmodified) SIM-BMP security.

Paper Nr: 63
Title:

SLAP: Secure Lightweight Authentication Protocol for Resource-constrained Devices

Authors:

Giulio Aliberti, Roberto Di Pietro and Stefano Guarino

Abstract: Motivated by the upcoming Internet of Things, designing light-weight authentication protocols for resource constrained devices is among the main research directions of the last decade. Current solutions in the literature attempt either to improve the computational efficiency of cryptographic authentication schemes, or to build a provably-secure scheme relying on the hardness of a specific mathematical problem. In line with the principles of information-theoretic security, in this paper we present a novel challenge-response protocol, named SLAP, whose authentication tokens only leak limited information about the secret key, while being very efficient to be generated. We do support our proposal with formal combinatorial arguments, further sustained by numeric evaluations, that clarify the impact of system parameters on the security of the protocol, yielding evidence that SLAP allows performing a reasonable number of secure authentication rounds with the same secret key.

Paper Nr: 71
Title:

Using a History-based Profile to Detect and Respond to DDoS Attacks

Authors:

Negar Mosharraf, Anura P. Jayasumana and Indrakshi Ray

Abstract: Distributed Denial-of-Service (DDoS) attack has been identified among the most serious threat to service availability on the Internet. It prevents legitimate users from accessing the victim node by flooding and consuming network resources. In order to combat such attacks, a distributed defense mechanism is needed that will thwart the attack traffic in real time. We propose one such mechanism that when deployed is able to filter out malicious and allow legitimate traffic to the extent possible during the attack period. We characterize the network traffic and introduce a new history-based profile algorithm that filters potential attack traffic and aims to maximize the flow of legitimate traffic in the event of an attack. We investigate the features of network traffic that can be used to do such filtration. We use a Bloom filter based mechanism to efficiently implement the history-based profile model which serves to reduce the communication and computation costs. We evaluate our scheme using simulations on recent real-world traffic datasets. The experimental results demonstrate the effectiveness of our scheme. In order to improve communication and computation costs even further, we propose using three octets of the IP address instead of the whole address. We also demonstrate how using three octets of IP address impacts the accuracy, efficiency, and memory requirement of the filtering mechanism.

Paper Nr: 81
Title:

LOCALPKI: A User-Centric Formally Proven Alternative to PKIX

Authors:

Jean-Guillaume Dumas, Pascal Lafourcade, Francis Melemedjian, Jean-Baptiste Orfila and Pascal Thoniel

Abstract: Abstract. A public-key infrastructure (PKI) binds public keys to identities of entities. Usually, this binding is established through a process of registration and issuance of certificates by a certificate authority (CA) where the validation of the registration is performed by a local registration authority. In this paper, we pro- pose an alternative scheme, called L OCALPKI, where the binding is performed by the local authority and the issuance is left to the end user or to the local au- thority. The role of our third entity is then to register this binding and to provide up-to-date status information on this registration. The idea is that many more lo- cal actors could then take the role of a local authority, thus allowing for an easier spread of public-key certificates in the population. We formally prove the security of this new scheme and show how to deploy it using existing tools and protocols.

Paper Nr: 82
Title:

Practical Passive Leakage-abuse Attacks Against Symmetric Searchable Encryption

Authors:

Matthieu Giraud, Alexandre Anzala-Yamajako, Olivier Bernard and Pascal Lafourcade

Abstract: Symmetric Searchable Encryption (SSE) schemes solve efficiently the problem of securely outsourcing client data with search functionality. These schemes are provably secure with respect to an explicit leakage profile; however, determining how much information can be inferred in practice from this leakage remains difficult. First, we recall the leakage hierarchy introduced in 2015 by Cash et al. Second, we present complete practical attacks on SSE schemes of L4, L3 and L2 leakage profiles which are deployed in commercial cloud solutions. Our attacks are passive and only assume the knowledge of a small sample of plaintexts. Moreover, we show their devastating effect on real-world data sets since, regardless of the leakage profile, an adversary knowing a mere 1% of the document set is able to retrieve 90% of documents whose content is revealed over 70%. Then, we further extend the analysis of existing attacks to highlight the gap of security that exists between L2- and L1-SSE and give some simple countermeasures to prevent our attacks.

Paper Nr: 99
Title:

Constant-size Threshold Attribute based SignCryption for Cloud Applications

Authors:

Sana Belguith, Nesrine Kaaniche, Maryline Laurent, Abderrazak Jemai and Rabah Attia

Abstract: In this paper, we propose a novel constant-size threshold attribute-based signcryption scheme for securely sharing data through public clouds. Our proposal has several advantages. First, it provides flexible cryptographic access control, while preserving users' privacy as the identifying information for satisfying the access control policy are not revealed. Second, the proposed scheme guarantees both data origin authentication and anonymity thanks to the novel use of attribute based signcryption mechanism, while ensuring the unlinkability between the different access sessions. Third, the proposed signcryption scheme has efficient computation cost and constant communication overhead whatever the number of involved attributes. Finally, our scheme satisfies strong security properties in the random oracle model, namely Indistinguishability against the Adaptive Chosen Ciphertext Attacks (IND-CCA2), Existential Unforgeability against Chosen Message Attacks (EUF-CMA) and privacy preservation of the attributes involved in the signcryption process, based on the assumption that the augmented Multi-Sequence of Exponents Decisional Diffie-Hellman (aMSE-DDH) problem and the Computational Diffie Hellman Assumption (CDH) are hard.

Short Papers
Paper Nr: 5
Title:

Accelerating Square Root Computations Over Large GF (2m)

Authors:

Salah Harb and Moath Jarrah

Abstract: The communication networks of low-resources applications require implementing cryptographic protocols and operations with less computational and architectural complexities. In this paper, an efficient method for high speed calculations of square (SQR) root is proposed over Galois Fields GF (2m). The method is based on using the results of certain pre-computations, and transforming the SQR root calculations into a system of linear equations. The computational complexity of our proposed method for computing the SQR root in GF (2m) is O(m) which is significantly better than existing methods such as Tonelli-Shanks and Cipolla. Our proposed method was implemented using different types of multipliers over several polynomial degrees. Software and hardware implementations were developed in NTL-C++ and VHDL, respectively. Our software experimental results show up to 38 times faster than Doliskani & Schost method. Moreover, our method is 840 times faster than Tonelli-Shanks method. In terms of hardware implementation and since Tonelli-Shanks requires less resources than Doliskani & Schost, we compare our method with Tonelli-Shanks. The hardware experimental results show that up to 50% less LUTs with a speedup of 18% that can be obtained compared to Tonelli-Shanks method.

Paper Nr: 6
Title:

SAT-based Cryptanalysis of Authenticated Ciphers from the CAESAR Competition

Authors:

Ashutosh Dhar Dwivedi, Miloš Klouček, Paweł Morawiecki, Ivica Nikolić, Josef Pieprzyk and Sebastian Wójtowicz

Abstract: We investigate six authenticated encryption schemes (ACORN, ASCON-128a, ICEPOLE-128a, Ketje Jr, MORUS, and NORX-32) from the CAESAR competition. We aim at state recovery attacks using a SAT solver as a main tool. Our analysis reveals that these schemes, as submitted to CAESAR, provide strong resistance against SAT-based state recoveries. To shed a light on their security margins, we also analyse modified versions of these algorithms, including round-reduced variants and versions with higher security claims. Our attacks on such variants require only a few known plaintext-ciphertext pairs and small memory requirements (to run the SAT solver), whereas time complexity varies from very practical (few seconds on a desktop PC) to ‘theoretical’ attacks.

Paper Nr: 9
Title:

On Obfuscating Compilation for Encrypted Computing

Authors:

Peter T. Breuer, Jonathan Bowen, Esther Palomar and Zhiming Liu

Abstract: This paper investigates conditions for privacy and security of data against the privileged operator on processors that ‘work encrypted’. A compliant machine code architecture plus an ‘obfuscating’ compiler turns out to be both necessary and sufficient to achieve that, the combination mathematically assuring the privacy of user data in arbitrary computations in an encrypted computing context.

Paper Nr: 20
Title:

Privacy-preserving Regression on Partially Encrypted Data

Authors:

Matús Harvan, Thomas Locher, Marta Mularczyk and Yvonne Anne Pignolet

Abstract: There is a growing interest in leveraging the computational resources and storage capacities of remote compute and storage infrastructures for data analysis. However, the loss of control over the data raises concerns about data privacy. In order to remedy these concerns, data can be encrypted before transmission to the remote infrastructure, but the use of encryption renders data analysis a challenging task. An important observation is that it suffices to encrypt only certain parts of the data in various real-world scenarios, which makes it possible to devise efficient algorithms for secure remote data analysis based on partially homomorphic encryption. We present several computationally efficient algorithms for regression analysis, focusing on linear regression, that work with partially encrypted data. Our evaluation shows that we can both train models and compute predictions with these models quickly enough for practical use. At the expense of full data confidentiality, our algorithms outperform state-of-the-art schemes based on fully homomorphic encryption or multi-party computation by several orders of magnitude.

Paper Nr: 24
Title:

Mining Encrypted Software Logs using Alpha Algorithm

Authors:

Gamze Tillem, Zekeriya Erkin and Reginald L. Lagendijk

Abstract: The growing complexity of software with respect to technological advances encourages model-based analysis of software systems for validation and verification. Process mining is one recently investigated technique for such analysis which enables the discovery of process models from event logs collected during software execution. However, the usage of logs in process mining can be harmful to the privacy of data owners. While for a software user the existence of sensitive information in logs can be a concern, for a software company, the intellectual property of their product and confidential company information within logs can pose a threat to company’s privacy. In this paper, we propose a privacy-preserving protocol for the discovery of process models for software analysis that assures the privacy of users and companies. For this purpose, our proposal uses encrypted logs and processes them using cryptographic protocols in a two-party setting. Furthermore, our proposal applies data packing on the cryptographic protocols to optimize computations by reducing the number of repetitive operations. The experiments show that using data packing the performance of our protocol is promising for privacy-preserving software analysis. To the best of our knowledge, our protocol is the first of its kind for the software analysis which relies on processing of encrypted logs using process mining techniques.

Paper Nr: 25
Title:

Differential and Rotational Cryptanalysis of Round-reduced MORUS

Authors:

Ashutosh Dhar Dwivedi, Pawel Morawiecki and Sebastian Wójtowicz

Abstract: In this paper we investigate the security margin of MORUS—an authenticated cipher taking part in the CAESAR competition. We propose a new key recovery approach, which can be seen as an accelerated exhaustive search. We also verify the resistance of MORUS against internal differential and rotational cryptanalysis. Our analysis reveals that the cipher has a solid security margin and a lack of round constants does not bring any weakness. Our work helps to reliably evaluate this new, high-performance algorithm, which is particularly important in the context of the ongoing CAESAR competition.

Paper Nr: 32
Title:

The Semantic Discrimination Rate Metric for Privacy Measurements which Questions the Benefit of t-closeness over l-diversity

Authors:

Louis Philippe Sondeck, Maryline Laurent and Vincent Frey

Abstract: After a brief description of k-anonymity, l-diversity and t-closeness techniques, the paper presents the Discrimination Rate (DR) as a new metric based on information theory for measuring the privacy level of any anonymization technique. As far as we know, the DR is the first approach supporting fine grained privacy measurement down to attribute’s values. Increased with the semantic dimension, the resulting semantic DR (SeDR) enables to: (1) tackle anonymity measurements from the attacker’s perspective, (2) prove that t-closeness can give lower privacy protection than l-diversity.

Paper Nr: 33
Title:

One Random Jump and One Permutation: Sufficient Conditions to Chaotic, Statistically Faultless, and Large Throughput PRNG for FPGA

Authors:

Mohammed Bakiri, Jean-François Couchot and Christophe Guyeux

Abstract: Sub-categories of mathematical topology, like the mathematical theory of chaos, offer interesting applications devoted to information security. In this research work, we have introduced a new chaos-based pseudorandom number generator implemented in FPGA, which is mainly based on the deletion of a Hamilton cycle within the n-cube (or on the vectorial negation), plus one single permutation. By doing so, we produce a kind of post-treatment on hardware pseudorandom generators, but the obtained generator has usually a better statistical profile than its input, while running at a similar speed. We tested 6 combinations of Boolean functions and strategies that all achieve to pass the most stringent TestU01 battery of tests. This generation can reach a throughput/latency ratio equal to 6.7 Gbps, being thus the second fastest FPGA generator that can pass TestU01.

Paper Nr: 34
Title:

(In) Security in Graph Databases - Analysis and Data Leaks

Authors:

Miguel Hernández Boza and Alfonso Muñoz Muñoz

Abstract: Graph databases are an emerging technology useful in the field of cybersecurity, especially in the detection of new threats based on the correlation of diverse sources of information. In our research, we had reviewed the design of the most widespread graph databases, for example Neo4J and OrientDB, detecting several security problems, improper default configurations and leaks, scanning the Internet during 9 months. To repeat our proofs, we are releasing the first hacking tool for testing and detecting (in) secure graph databases, GraFScaN.

Paper Nr: 35
Title:

PB-PKI: A Privacy-aware Blockchain-based PKI

Authors:

Louise Axon and Michael Goldsmith

Abstract: Conventional public-key infrastructure (PKI) designs using certificate authorities and web-of-trust are not optimal and have security flaws. The properties afforded by the Bitcoin blockchain are a natural solution to some of the problems with PKI - in particular, certificate transparency and elimination of single points-offailure. Proposed blockchain-based PKI designs are built as public ledgers linking identity with public key, providing no privacy. We consider cases requiring privacy-aware PKIs, which do not link identity with public key. We show that blockchain technology can be used to construct a privacy-aware PKI while eliminating some of the problems of conventional PKI, and present PB-PKI, a privacy-aware blockchain-based PKI.

Paper Nr: 36
Title:

RmPerm: A Tool for Android Permissions Removal

Authors:

Simone Aonzo, Giovanni Lagorio and Alessio Merlo

Abstract: Android apps are generally over-privileged, i.e., they request more permissions than they actually need to execute properly. Prior to version 6 users can install an app only by accepting all its requested permissions, while newer Android versions allow users to dynamically grant/deny groups of permissions. Since some them impact on users’ privacy, we argue that users should be granted control at the granularity of the single permission. We propose a novel approach, which does not require any change to the underlying OS, allowing users to selectively remove permissions from apps before installing them, and with a finer granularity. We developed RmPerm, an open-source tool, that implements our methodology, and we present the viability of our approach via an empirical assessment on 81K apps, underlining that, in the worst case, up to 86% of the apps can execute without crashing when none of the requested privacy-related permissions are granted.

Paper Nr: 40
Title:

HAIT: Heap Analyzer with Input Tracing

Authors:

Andrea Atzeni, Andrea Marcelli, Francesco Muroni and Giovanni Squillero

Abstract: Heap exploits are one of the most advanced, complex and frequent types of attack. Over the years, many effective techniques have been developed to mitigate them, such as data execution prevention, address space layout randomization and canaries. However, if both knowledge and control of the memory allocation are available, heap spraying and other attacks are still feasible. This paper presents HAIT, a memory profiler that records critical operations on the heap and shows them graphically in a clear and comprehensible format. A prototype was implemented on top of Triton, a framework for dynamic binary analysis. The experimental evaluation demonstrates that HAIT can help identifying the essential information needed to carry out heap exploits, providing valuable knowledge for an effective attack.

Paper Nr: 53
Title:

Evaluating Credit Card Transactions in the Frequency Domain for a Proactive Fraud Detection Approach

Authors:

Roberto Saia and Salvatore Carta

Abstract: The massive increase in financial transactions made in the e-commerce field has led to an equally massive increase in the risks related to fraudulent activities. It is a problem directly correlated with the use of credit cards, considering that almost all the operators that offer goods or services in the e-commerce space allow their customers to use them for making payments. The main disadvantage of these powerful methods of payment concerns the fact that they can be used not only by the legitimate users (cardholders) but also by fraudsters. Literature reports a considerable number of techniques designed to face this problem, although their effectiveness is jeopardized by a series of common problems, such as the imbalanced distribution and the heterogeneity of the involved data. The approach presented in this paper takes advantage of a novel evaluation criterion based on the analysis, in the frequency domain, of the spectral pattern of the data. Such strategy allows us to obtain a more stable model for representing information, with respect to the canonical ones, reducing both the problems of imbalance and heterogeneity of data. Experiments show that the performance of the proposed approach is comparable to that of its state-of-the-art competitor, although the model definition does not use any fraudulent previous case, adopting a proactive strategy able to contrast the cold-start issue.

Paper Nr: 69
Title:

Some Remarks about Tracing Digital Cameras – Faster Method and Usable Countermeasure

Authors:

Jaroslaw Bernacki, Marek Klonowski and Piotr Syga

Abstract: In this paper we consider the issue of tracing digital cameras by analyzing pictures they produced. Clearly, the possibility of establishing if a picture was taken by a given camera or even if two pictures come from cameras of the same model can expose users’ privacy to a serious threat. In the paper, at first, we propose a simple and ultra-fast algorithm for identification of the brand of a digital camera and compare the results with the state-of-the-art algorithm by Lukás et al.’s. Experimental results show that at the cost of a moderate decrease of accuracy, our method is significantly faster, thus can be used for an analysis of large batches of pictures or as a preprocessing for more exact. In the second part, we propose a method for limiting the possibility of tracing digital cameras. Our method is a transformation of the picture that can be classified as a type of standardization. We prove that it prevents all methods of tracing cameras based on analysis of histograms. Moreover, in an extensive experimental evaluation we demonstrate that the transformed pictures are very similar to the original images under both visual and objective numerical measure inspection.

Paper Nr: 70
Title:

Adding Privacy Protection to Distributed Software Systems

Authors:

George O. M. Yee

Abstract: Distributed software systems are increasingly found in many aspects of our lives, as can be seen in social media, international online banking, and international commerce (e.g. Internet shopping). This widespread involvement of software in our lives has led to the need to protect privacy, as the use of the software often requires us to input our personal or private information. A first step to protecting privacy is to identify the risks to privacy found in the software system. Once the risks are known, measures can be put in place to mitigate the risks. This is best done at the early stages of software development due to the heavy costs of making changes after the software is deployed. This paper proposes a two-pronged approach, consisting of privacy risk identification followed by risk mitigation, for adding privacy protection to distributed software. The paper illustrates the approach with examples.

Paper Nr: 91
Title:

PAnTHErS: A Prototyping and Analysis Tool for Homomorphic Encryption Schemes

Authors:

Cyrielle Feron, Vianney Lapotre and Loïc Lagadec

Abstract: Homomorphic Encryption (HE) enables third parties to process data without requiring a plaintext access to it. Its future is promising to solve Cloud Computing security issues. Still, HE is not yet usable in real cases due to complexity issues. For every new HE scheme, evaluation is of primary importance, but performances (execution time and memory cost) for various sets of parameters are currently difficult to estimate ahead of practical implementations. This paper introduces PAnTHErS, a Prototyping and Analysis Tool for Homomorphic Encryption Schemes that alleviates the need for implementation to estimate the performances of any new HE scheme. PAnTHErS supports parametric modeling of HE schemes and provides analysis features. In this paper, PAnTHErS is illustrated over some HE schemes and shows promising results.

Paper Nr: 94
Title:

Cryptographic Service Providers in Current Device Landscapes: An Inconvenient Truth

Authors:

Florian Reimair, Johannes Feichtner, Dominik Ziegler, Sandra Kreuzhuber and Thomas Zefferer

Abstract: Current application and device landscapes became a harsh environment for data security. Multi-device users enjoy the convenience and efficiency of modern distributed applications in a highly heterogeneous device landscape. However, today's data protection mechanisms fell behind in taking care of some current use cases and application scenarios. We perform a case study and an in-depth security analysis and risk assessment on a simplified set of three different cryptographic service provider types; software, hardware, and remote. Our case study shows that different provider types can change application characteristics considerably. Our security analysis and risk assessment shows how different provider types can influence the security properties of a set of use cases. We found that no one provider can excel for every cryptographic task. Based on these findings we formulate a list of features which we believe are crucial to get the data protection mechanisms up to speed again so that everyone can again benefit from data security even in a world of highly distributed applications and data.

Paper Nr: 98
Title:

The Net Rat - Rethinking Connected Services for Increased Security

Authors:

Bernd Prünster, Florian Reimair and Andreas Reiter

Abstract: Traditional desktop computers have been outranked in terms of usage numbers by mobile devices. Still, many popular mobile-first services rely on workflows designed decades ago for a different environment. When relying on cloud-based services, privacy and data protection issues need to be considered. Mostly, however, one can choose between either well-supported legacy applications or innovative niche solutions. In this paper, we introduce the Net Rat, a framework enabling a seamless transition from existing centralised setups to decentralised state-of-the-art services, increasing security while maintaining backwards compatibility to well-established legacy services. We demonstrate the feasibility of our approach with a case study focusing on the decentralisation of the e-mail service—until now, this failed due to missing backward compatibility. A security analysis demonstrates how our approach reaches its goal of protecting user data through decentralisation. The Net Rat is built on a solid foundation as result of a security-first design. The results of this work clearly show the feasibility of decentralising existing services and highlight how well-established services can be improved. Our approach also presents opportunities to develop new services based on a solid foundation.

Paper Nr: 114
Title:

Efficient Heuristic Safety Analysis of Core-based Security Policies

Authors:

Peter Amthor

Abstract: Being of paramount importance for the correctness of a security policy, the property of safety has received decades of attention in the field of model-based security engineering. To analyze the safety of a security model, heuristic approaches are used to avoid restrictions of the model calculus while accepting semi-decidability of this property. Within this field, this paper addresses three open problems concerning the DEPSEARCH heuristic safety analysis framework: Inefficient state-space exploration, static verification of unsafety-unsatisfiability, and parameter dependency analysis. We describe these problems on a formal basis, specify solution proposals, and implement these in the current, model-independent fDS framework. A practical evaluation based on SELinux is performed to study effectiveness and future optimization of the framework.

Posters
Paper Nr: 4
Title:

Short Paper: Industrial Feasibility of Private Information Retrieval

Authors:

Angela Jäschke, Björn Grohmann, Frederik Armknecht and Andreas Schaad

Abstract: A popular security problem in database management is how to guarantee to a querying party that the database owner will not learn anything about the data that is retrieved — a problem known as Private Information Retrieval (PIR). While a variety of PIR schemes are known, they are rarely considered for practical use cases yet. We investigate the feasibility of PIR in the telecommunications world to open up data of carriers to external parties. To this end, we first provide a comparative survey of the current PIR state of the art (including ORAM schemes as a generalized concept) as well as implementation and analysis of two PIR schemes for the considered use case. While an overall conclusion is that PIR techniques are not too far away from practical use in specific cases, we see ORAM as a more suitable candidate for further R&D investment.

Paper Nr: 13
Title:

A Probabilistic Baby-step Giant-step Algorithm

Authors:

Prabhat Kushwaha and Ayan Mahalanobis

Abstract: In this paper, a new algorithm to solve the discrete logarithm problem is presented which is similar to the usual baby-step giant-step algorithm. Our algorithm exploits the order of the discrete logarithm in the multiplicative group of a finite field. Using randomization with parallelized collision search, our algorithm indicates some weakness in NIST curves over prime fields which are considered to be the most conservative and safest curves among all NIST curves.

Paper Nr: 17
Title:

Vector Quantization based Steganography for Secure Speech Communication System

Authors:

Bekkar Laskar and Merouane Bouzid

Abstract: Data hiding (steganography or watermarking) involves embedding secret data into various forms of digital media such as text, audio, image and video. In this paper we propose two variants of vector quantization (VQ) based steganography method to hide secret speech signal in host public speech coded by the AMR-WB (Rec. G.722.2). The secret bit stream is hidden by using the basic principle of binning scheme which is carried out in the split-multistage vector quantization of G.722.2 immittance spectral frequencies (ISF) parameters.

Paper Nr: 26
Title:

GLITCH: A Discrete Gaussian Testing Suite for Lattice-based Cryptography

Authors:

James Howe and Máire O'Neill

Abstract: Lattice-based cryptography is one of the most promising areas within post-quantum cryptography, and offers versatile, efficient, and high performance security services. The aim of this paper is to verify the correctness of the discrete Gaussian sampling component, one of the most important modules within lattice-based cryptography. In this paper, the GLITCH software test suite is proposed, which performs statistical tests on discrete Gaussian sampler outputs. An incorrectly operating sampler, for example due to hardware or software errors, has the potential to leak secret-key information and could thus be a potential attack vector for an adversary. Moreover, statistical test suites are already common for use in pseudo-random number generators (PRNGs), and as lattice-based cryptography becomes more prevalent, it is important to develop a method to test the correctness and randomness for discrete Gaussian sampler designs. Additionally, due to the theoretical requirements for the discrete Gaussian distribution within lattice-based cryptography, certain statistical tests for distribution correctness become unsuitable, therefore a number of tests are surveyed. The final GLITCH test suite provides 11 adaptable statistical analysis tests that assess the exactness of a discrete Gaussian sampler, and which can be used to verify any software or hardware sampler design.

Paper Nr: 30
Title:

Program Execution Analysis using UserAssist Key in Modern Windows

Authors:

Bhupendra Singh and Upasna Singh

Abstract: The construction of user activity timeline related to digital incident being investigated is part of most of the forensic investigations. Sometimes, it is desirable to know the programs executed on a system, and more importantly, when and from where these programs were launched. Program execution analysis is very meaningful effort both for forensic and malware analysts. The UserAssist key, a part of Microsoft Windows registry, records the information related to programs run by a user on a Windows system. This paper seeks thorough investigation of UserAssist key, as a resource for program execution analysis. In this paper, the binary structure of UserAssist key in modern Windows (Windows 7/8/10) is presented and compared with that in older versions of Windows (e.g., Windows XP). Several experiments were carried out to record the behavior of UserAssist key when programs were executed from various sources, such as USB device, Windows store and shared network. These artifacts were found to persist even after the applications have been uninstalled/deleted from the system. In the area of program execution analysis, the paper highlights the forensic capability of UserAssist key and compares it with that from similar sources, such as IconCache.db, SRUDB.dat, Prefetch, Amcache.hve and Shortcut (.lnk) files, in order to summarize what information can and cannot be determined from these sources.

Paper Nr: 31
Title:

Capturing the Effects of Attribute based Correlation on Privacy in Micro-databases

Authors:

Debanjan Sadhya, Bodhi Chakraborty and Sanjay Kumar Singh

Abstract: In the modern data driven era, it is a very common practice for individuals to provide their personalized data in multiple databases. However, the existence of correlated information in between these databases is a common source of privacy risk for the database users. In our study, we investigate such scenarios for attribute based linking attacks. These attacks refer to the common strategy by which an adversary can breach the privacy of the database respondents via exploiting the correlated information among the database attributes. In our work, we have proposed an information theoretic framework through which the achievable privacy levels following an adversarial linking attack are quantified. Our developed model also incorporates various aspects associated with micro-databases such as sanitization mechanism and auxiliary side information, thereby providing a more holistic structure to our theoretical framework. A comparative analysis of the various cases associated with our model theoretically confirms the notion that a sanitization mechanism facilitates in preserving the original privacy levels of the users.

Paper Nr: 45
Title:

Improving Throughput in BB84 Quantum Key Distribution

Authors:

Shawn Prestridge and James Dunham

Abstract: Quantum Key Distribution (QKD) is a scheme that allows two parties to exchange a key in a provably secure manner that will be used in a more conventional encryption system. The first implementation of QKD was BB84 by Bennett and Brassard. Several techniques have been used to attempt to maximize the number of bits realized at the end of the BB84 protocol. One of the techniques used is the B92 protocol (and its followon, CASCADE) introduced by Bennett et al. which uses 1-bit parities to reconcile the keystream between Alice and Bob (Bennett et al., 1992). Another is the Winnow protocol introduced by Buttler et al. which uses Hamming codes to increase the efficiency of the BB84 protocol to allow error rates up to 13.22%(Buttler et al., 2003). In this paper, the Winnow protocol is enhanced and extended to allow arbitrarily high error rates thus greatly improving the effectiveness of the protocol while preserving security. This enhancement also provides a marked improvement over the original B92 protocol in terms of the number of bits preserved in the keystream.

Paper Nr: 55
Title:

A Review of PROFIBUS Protocol Vulnerabilities - Considerations for Implementing Authentication and Authorization Controls

Authors:

Venesa Watson, Xinxin Lou and Yuan Gao

Abstract: PROFIBUS is a standard for fieldbus communication, used in industrial networks to support real-time command and control. Similar to network protocols developed then, availability is the security objective prioritized in the PROFIBUS design. Confidentiality and integrity were of lesser importance, as industrial protocols were not intended for public access. However, the publicized weaknesses in industrial technologies, including the inclusion of publicly available technology and protocols in industrial networks, presents major risks to industrial networks. This paper investigates the security risks of and provides suggested security solutions for PROFIBUS. The objective is to review the PROFIBUS protocol, to establish the purposefulness of the design and its suitability for the applications where it forms a core part of the infrastructure. The security risks of this protocol are then assessed from successful and possible attacks, based on the vulnerabilities. Proposed security solutions are reviewed and additional recommendations made concerning the use of OPC UA, accompanied by an analysis of the cost of these solutions to the efficiency and safety of the PROFIBUS. The findings of this paper indicate that a defense-in-depth approach is more feasible security solution, with strong security controls being implemented at networks interconnecting with the PROFIBUS networks.

Paper Nr: 58
Title:

FlowSlicer - A Hybrid Approach to Detect and Avoid Sensitive Information Leaks in Android Applications using Program Slicing and Instrumentation

Authors:

Luis Menezes and Roland Wismüller

Abstract: With the increasingly amount of private information stored in mobile devices, the need for more secure ways to detect, control and avoid malicious behaviors has become higher. The too coarse-grained permission system implemented in the Android platform does not cover problems regarding the flow of the data acquired by the apps. In order to enhance detection, awareness and avoidance of such unwanted information flows, we propose a hybrid information flow analysis that mixes the benefits of static and dynamic analysis, using slicing and instrumentation. Our results indicate a precise detection and only a small overhead while running the application. The validation of our method has been done by creating a tool called FLOWSLICER and using the category AndroidSpecific from the DROIDBENCH repository of applications with known information leaks.

Paper Nr: 64
Title:

A Card-less TEE-based Solution for Trusted Access Control

Authors:

Mohamed Amine Bouazzouni, Emmanuel Conchon, Fabrice Peyrard and Pierre-François Bonnefoi

Abstract: In this paper, we present a new card-less access control system aiming to replace existing systems based on vulnerable contact-less cards. These existing systems have many vulnerabilities which makes them not secure enough to be deployed to protect restricted areas. We propose to deploy a new access control architecture based on the use of a smartphone to remove the physical card. Our secure access control system is based on Trusted Execution Environment (TEE) in the cloud and Identity Based Encryption (IBE) mechanisms. The authentication protocol deployed on our architecture is based on IBAKE. Finally, a performance evaluation of the protocol is provided.

Paper Nr: 65
Title:

s2ipt: A Lightweight Network Intrusion Detection/Prevention System based on IPtables

Authors:

Gerardo Canfora, Antonio Pirozzi and Aaron Visaggio

Abstract: Since each organization has its own security culture and background, there is not an out-of-the-box solution that fits all the possible security requirements. There may be some contexts in which it is necessary to monitor and prevent certain application-level attacks with less impact on pre-existent configuration. For example, there may be some constraints on processing resources of some embedded devices. Starting from this consideration, we developed s2ipt, a python-powered tool which aims to implement a lightweight Netfilter-based network intrusion detection and prevention system (IDS/IPS) by translating Snort community rules into iptables rulesset. s2ipt utilizes the netfilter string matching module to detect application-level attacks. Netfilter reduces the impact on a system, has less memory and CPU footprint, which makes it suitable to run even on low-cost devices than a solution like Snort. s2ipt allows iptables to detect application layer attacks in a transparent way, in fact it only adds new application layer ruleset leaving the existing ones unchanged.

Paper Nr: 67
Title:

Reputation Management in Online Social Networks - A New Clustering-based Approach

Authors:

Sana Hamdi, Alda Lopes Gançarski, Amel Bouzeghoub and Sadok Ben Yahia

Abstract: Trust and reputation management stands as a corner stone within the Online Social Networks (OSNs) since they ensure a healthy collaboration relationship among participants. Currently, most trust and reputation systems focus on evaluating the credibility of the users. The reputation systems in OSNs have as objective to help users to make difference between trustworthy and untrustworthy, and encourage honest users by rewarding them with high trust values. Computing reputation of one user within a network requires knowledge of trust degrees between the users. In this paper, we propose a new Clustering Reputation algorithm, called RepC, based on trusted network. This algorithm classifies the users of OSNs by their trust similarity such that most trustworthy users belong to the same cluster. We conduct extensive experiments on a real online social network dataset from Twitter. Experimental results show that our algorithm generates better results than do the pioneering approaches of the literature.

Paper Nr: 72
Title:

Interaction Platform for Improving Detection Capability of Dynamic Application Security Testing

Authors:

Jonghwan Im, Jongwon Yoon and Minsik Jin

Abstract: Dynamic application security testing detects security vulnerabilities by sending predefined strings to web applications. So if the web applications have filters which restrict input parameters, the detection capability of dynamic application security testing is degraded. To solve this problem, interactive application security testing have emerged in which dynamic application security testing interact with static application security testing. In this paper, we propose an interactive platform for storing, processing, and distributing information collected from each security test in the software development life cycle. And we use this platform to verify that we can detect cross-site script vulnerabilities that could not be detected due to web application filters. Experiments on the proposed approach for the cross-site script vulnerability test case of OWASP Benchmark show that the detection rate of the dynamic analyzer is improved by about 32.11%.

Paper Nr: 75
Title:

Strong Authentication for e-Banking: A Survey on European Regulations and Implementations

Authors:

Federico Sinigaglia, Roberto Carbone and Gabriele Costa

Abstract: The modern, smart society needs a reliable and trustworthy access to the internet of services. Strong authentication mechanisms promise to rise the bar of security and they are polarizing the attention of both institutional and industrial stakeholders. In this survey, we take stock of the strong authentication mechanisms used by e-Banking services in terms of regulations and implementations. To this aim, we reviewed the EU regulations and their evolution in the last decade and we analyzed the strong authentication mechanisms implemented by 26 major EU and non-EU banks.

Paper Nr: 77
Title:

A Lightweight Online Advertising Classification System using Lexical-based Features

Authors:

Xichen Zhang, Arash Habibi Lashkari and Ali A. Ghorbani

Abstract: Due to the significant development of online advertising, malicious advertisements have become one of the major issues to distribute scamming information, click fraud and malware. Most of the current approaches are involved with using filtering lists for online advertisements blocking, which are not scalable and need manual maintenance. This paper presents a lightweight online advertising classification system using lexical-based features as an alternative solution. In order to imitate real-world cases, three different scenarios are generated depending on three different URL sources. Then a set of URL lexical-based features are selected from previous researches in the purpose of training and testing the proposed model. Results show that by using lexical-based features, advertising detection accuracy is about 97% in certain scenarios.

Paper Nr: 83
Title:

Formal Analyze of a Private Access Control Protocol to a Cloud Storage

Authors:

Mouhebeddine Berrima, Pascal Lafourcade, Matthieu Giraud and Narjes Ben Rajeb

Abstract: Storing data in the Cloud makes challenging data’s security and users’ privacy. To address these problems cryptographic protocols are usually designed. Cryptographic primitives have to guarantee some security properties such that for instance data and user privacy or authentication. Attribute-Based Signature (ABS) and Attribute-Based Encryption (ABE) are very suitable for storing data on an untrusted remote entity. In this work, we formally analyse the Ruj et al. protocol of cloud storage based on ABS and ABE schemes. Our analysis clarifies several ambiguities in the design of this protocol and reveals an unknown attack against user privacy. We propose a correction, and prove the security of the corrected protocol.

Paper Nr: 85
Title:

Differential-linear and Impossible Differential Cryptanalysis of Round-reduced Scream

Authors:

Ashutosh Dhar Dwivedi, Pawel Morawiecki and Sebastian Wójtowicz

Abstract: In this work we focus on the tweakable block cipher Scream, We have analysed Scream with the techniques, which previously have not been applied to this algorithm, that is differential-linear and impossible differential cryptanalysis. This is work in progress towards a comprehensive evaluation of Scream. We think it is essential to analyse these new, promising algorithms with a possibly wide range of cryptanalytic tools and techniques. Our work helps to realize this goal.

Paper Nr: 87
Title:

Experimental Assessment of Private Information Disclosure in LTE Mobile Networks

Authors:

Stig F. Mjølsnes and Ruxandra F. Olimid

Abstract: Open source software running on SDR (Software Defined Radio) devices now allow building a full-fledged mobile network at low cost. These novel tools open up for exciting possibilities to analyse and verify by experiments the behaviour of existing and emerging mobile networks in new lab environments, for instance at universities. We use SDR equipment and open source software to analyse the feasibility of disclosing private information that is sent over the LTE access network. We verify by experiments that subscriber identity information can be obtained both passively, by listening on the radio link, and actively, by running considerable low detectable rogue base stations to impersonate the commercial network. Moreover, we implement a downgrade attack (to non-LTE networks) with minimal changes to the open source software.

Paper Nr: 89
Title:

Towards a Self-adaptive Trust Management Model for VANETs

Authors:

Ilhem Souissi, Nadia Ben Azzouna and Tahar Berradia

Abstract: The vehicular ad hoc networks (VANETs) aim basically to enhance the traffic safety performance, improve the traffic efficiency and achieve a comfortable driving experience. To reach these purposes, it is crucial to ensure the security of this network. Trust is one of the key challenges for VANET security enhancement. Trust management aims to investigate the relationship between the different entities in the network in order to ensure that only trustworthy messages are delivered to drivers. Solutions for trust evaluation are not self-adaptively adjusted to discriminate between the requirements of each class of applications. Moreover, most of these solutions stand on the reputation to determine the trustworthiness of vehicles. However, reputation is not well-suited in VANET due to the absence of social connections between fast moving and distributed entities. In this paper, we present a self-adaptive trust management model that copes with the specifications of each class of applications in a different way in order to enhance the decision-making process, minimize both time and energy consumption for decision-making and improve the network’s security. In addition to reputation, similarity and behavior assessment, our model uses the correlation between the event and contextual information and further the risk assessment for decision-making.

Paper Nr: 93
Title:

On Efficient Access Control Mechanisms in Hierarchy using Unidirectional and Transitive Proxy Re-encryption Schemes

Authors:

Gaurav Pareek and Purushothama B. R.

Abstract: Proxy re-encryption is a cryptographic primitive used to transform a ciphertext under one public key such that it becomes a ciphertext under another public key using a re-encryption key. Depending on the properties featured by a proxy re-encryption scheme, it can be applied to a variety of applications. In this paper, we target one such application of proxy re-encryption – access control in hierarchy, to highlight an important research gap in its design. We study how a proxy re-encryption scheme that is both unidirectional and transitive can be useful for enforcing hierarchical access control with constant computation and storage overhead on its users irrespective of the depth of the hierarchy. Also, we present improvements on the existing re-encryption schemes to make it applicable to hierarchical key assignment and achieve performance closer to that in case of a unidirectional transitive proxy re-encryption scheme.

Paper Nr: 95
Title:

Privacy-preserving Disease Susceptibility Test with Shamir’s Secret Sharing

Authors:

Guyu Fan and Manoranjan Mohanty

Abstract: Recent advances in genomics have facilitated the development of personalized medicine, in which a patient's susceptibility to certain diseases and her compatibility with certain medications can be determined from her genetic makeup. Although this technology has many advantages, privacy of the patient is one of the major concerns due to the sensitivity of genomic data. In this paper, we propose a privacy-preserving scheme for computing a patient's susceptibility to a particular disease. Our scheme stores genomic data in hidden form and performs the disease susceptibility test in the hidden domain. To hide the data, we use Shamir's (l, n) secret sharing, which can be homomorphic to a xed number of multiplications and unlimited additions. Using Shamir's secret sharing, we create n shares and store the shares at n datacenters. The datacenters perform the susceptibility test on their shares and send the result (which is also hidden) to a hospital. Finally, the hospital obtains the secret result of the test by accessing at least k datacenters, where k = 2l - 1. In comparison to other works, our approach is more practical as it minimizes the involvement of the patient and incurs less overhead.

Paper Nr: 97
Title:

Anonymous Credentials with Practical Revocation using Elliptic Curves

Authors:

Petr Dzurenda, Jan Hajny, Lukas Malina and Sara Ricci

Abstract: Anonymous Attribute-Based Credential (ABC) schemes allow users to anonymously prove the ownership of their attributes, such as age, citizenship, gender. The ABC schemes are part of a larger group of cryptographic constructions called Privacy Enhancing Technologies (PETs), aiming to increase user's privacy. In the article, we present a new ABC scheme based on elliptic curves and HM12 scheme. The scheme provides anonymity, untraceability, unlinkability, selective disclosure of attributes, non-transferability, revocation and malicious user identification. By involving elliptic curves, we achieved faster verification phase (by 30%) and smaller communication cost between user and verifier (by 85%) compared to the original HM12 scheme, with equivalent or greater security level.

Paper Nr: 100
Title:

On the Application of Fuzzy Set Theory for Access Control Enforcement

Authors:

Diogo Domingues Regateiro, Óscar Mortágua Pereira and Rui L. Aguiar

Abstract: Access control is a vital part of any computer system. When it comes to access to data, deterministic access control models such as RBAC are still widely used today, but they lack the flexibility needed to support some recent scenarios. These include scenarios where users and data can be dynamically added to a system, which emerged from IoT and big data contexts. Such scenarios include data from network operators, smart cities, etc. Thus, models that are able to adapt to these dynamic environments are necessary. Non-deterministic access control models fall into this approach, as they introduce new ways of mapping users to permissions and resources, but lack the auditing capabilities of deterministic models. In this paper, the usage of these models will be defended and argued for. In particular, a solution based on fuzzy set theory is proposed as it is thought to be able to provide some flexibility benefits of non-deterministic models, while giving some assurance to security experts that the resources are not accessed by unexpected users.

Paper Nr: 104
Title:

Clustering-based Approach for Anomaly Detection in XACML Policies

Authors:

Maryem Ait El Hadj, Meryeme Ayache, Yahya Benkaouz, Ahmed Khoumsi and Mohammed Erradi

Abstract: The development of distributed applications arises multiple security issues such as access control. Attribute-Based Access Control has been proposed as a generic access control model, which provides more flexibility and promotes information and security sharing. eXtensible Access Control Markup Language (XACML) is the most convenient way to express ABAC policies. However, in distributed environments, XACML policies become more complex and hard to manage. In fact, an XACML policy in distributed applications may be aggregated from multiple parties and can be managed by more than one administrator. Therefore, it may contain several anomalies such as conflicts and redundancies, which may affect the performance of the policy execution. In this paper, we propose an anomaly detection method based on the decomposition of a policy into clusters before searching anomalies within each cluster. Our evaluation results demonstrate the efficiency of the suggested approach.

Paper Nr: 107
Title:

Scenario-based Vulnerability Analysis in IoT-based Patient Monitoring System

Authors:

Neila Mekki, Mohamed Hamdi, Taoufik Aguili and Tai-Hoon Kim

Abstract: The Internet of Things (IoT) is one of the revolutionary technologies for healthcare. However, this flourishing still faces too many challenges including security and privacy preservation information. To address these problems, our contribution is to present a scenario of diabetes disease assume a matching between the situation of the patient and the relevant data from monitoring point view. This scenario describes how a patient can collect enormous of vital sign and activity. Wireless Body Sensor Networks (WBSN) is one of the IoT building blocks in which a patient can be monitored using a collection of sensor nodes to improve the patients quality of life. This technology in healthcare applications should not ignore security requirements. The aim of this paper is, (1) to design a healthcare architecture for a patient monitoring system, and (2) to explore the major security requirements in WBSN.

Paper Nr: 109
Title:

Fair and Accountable Anonymity for the Tor Network

Authors:

Jesus Diaz, David Arroyo and Francisco B. Rodriguez

Abstract: The balance between security and privacy is a must for the adequate construction of e-democracy. For such a goal, information and communication networks should not be hardened at the cost of lessening privacy protection mechanisms. In addition, the deployment of such mechanisms should not pave the way for performing malicious activities. This call for security-privacy trade-offs is specially relevant in the general scope of the anonymizing networks, and in the specific case of the Tor network. Indeed, general security attacks are based on anonymous network access, which makes service providers to ban this kind of connections even when they are initiated by legitimate users. In this communication we apply group and blind signatures to address this dilemma, allowing the incorporation of access controls to the Tor network. Our procedure is enhanced by a protocol for denouncing illegitimate actions without eroding users’ privacy.

Paper Nr: 110
Title:

Context-based Encryption Applied to Data Leakage Prevention Solutions

Authors:

Alberto García, Alberto Garcia Moro, Jose Javier García, Jorge Roncero, Víctor A. Villagrá and Helena Jalain

Abstract: Data leakage pose a serious threat to companies as the number of leakage incidents and the cost continues to increase. Data Leakage Prevention (DLP) has been studied to solve this information leakage. We propose a DLP solution applying context-based encryption concept, thus sensitive files are encrypted at all time. The cipher key is obtained through the execution of challenges based in the environment context and the company policies. In this paper, we explain the architecture and the design of our DLP system and the proposed challenges

Paper Nr: 111
Title:

Exploring USB Connection Vulnerabilities on Android Devices - Breaches using the Android Debug Bridge

Authors:

João Amarante and João Paulo Barros

Abstract: The complexity of avoiding vulnerabilities in the modern mobile operating systems makes them vulnerable to many types of attacks. This paper presents preliminary work in the creation of scenarios to surreptitiously extract private data from smartphones running different versions of the Android Operating System. Three scenarios were already identified and a proof of concept script was developed, all based on the use of the Android Debug Bridge tool. When running in a computer, the script is able to extract private data from a USB connected smartphone. In two scenarios it was possible to extract the information in a totally surreptitious way, without the user knowledge. In the third scenario, using a newer version of the Android operating system, a user action is needed which makes the attack less likely to succeed, but still possible.

Paper Nr: 113
Title:

Information Flows at OS Level Unmask Sophisticated Android Malware

Authors:

Valérie Viet Triem Tong, Aurélien Trulla, Mourad Leslous and Jean-François Lalande

Abstract: The detection of new Android malware is far from being a relaxing job. Indeed, each day new Android malware appear in the market and it remains difficult to quickly identify them. Unfortunately users still pay the lack of real efficient tools able to detect zero day malware that have no known signature. The difficulty is that most of the existing approaches rely on static analysis coupled with the ability of malware to hide their malicious code. Thus, we believe that it should be easier to study what malware do instead of what they contain. In this article, we propose to unmask Android malware hidden among benign applications using the observed information flows at the OS level. For achieving such a goal, we introduce a simple characterization of all the accountable information flows of a standard benign application. With such a model for benign apps, we lead some experiments evidencing that malware present some deviations from the expected normal behavior. Experiments show that our model recognizes most of the 3206 tested benign applications and spots most of the tested sophisticated malware (ransomware, rootkits, bootkit).

Paper Nr: 117
Title:

Privacy as a Currency: Un-regulated?

Authors:

Vishwas T. Patil and R. K. Shyamasundar

Abstract: We are living in a time where many of the decisions that affect us are made by mathematical models. These models rely on data. Precision and relevance of the decisions made by these models is dependent on quality of the data being fed to them. Therefore, there is a rush to collect personal data. Majority of the organizations that provide online services are at the forefront of collecting user data. Users, either voluntarily or by coercion, divulge information about themselves in return of personalized service, for example. These organizations’ revenue model is based on advertisement where advertisers are paired with user profiles that are built on top of collected data. This data is being used for a variety of purposes apart from delivering targeted advertisements. Mathematical decision models are impartial to the data on which they operate. An error, omission or mis-representation in data has an irrevocable consequence on our lives, at times, without corrective remedies. This paper touches upon various facets of information gathering; information bias, economics of privacy, information asymmetry – and their implications to our ecosystem if left unaddressed.