Gaurav Sharma

Author's posts

Jan 25

Seminar: Islam Debicha “Attacks against Intrusion Detection Systems” (Jan 26, 2021)

Feb 02, 2021 – 13.00

Speaker: Islam Debicha (ULB)

Title: “Attacks against Intrusion Detection Systems”
Short abstract: “Nowadays, Deep Neural Networks (DNNs) report state-of-the-art results in many machine learning areas, including intrusion detection. Nevertheless, recent studies in computer vision have shown that DNNs can be vulnerable to adversarial attacks that are capable of deceiving them into misclassification by injecting specially crafted data. In security-critical areas, such attacks can cause serious damage; therefore, in this paper, we examine the effect of adversarial attacks on deep learning-based intrusion detection. In addition, we investigate the effectiveness of adversarial training as a defense against such attacks. Experimental results show that with sufficient distortion, adversarial examples are able to mislead the detector and that the use of adversarial training can improve the robustness of intrusion detection.”

Jan 18

Seminar: Denis Verstraeten “Fair Trading in Blockchain” (Jan 19, 2021)

Jan 19, 2021 – 13.00

Speaker: Denis Verstraeten (ULB)

Title: “Fair Trading in Blockchain”
Short abstract: “Blockchains allow to have a decentralized ledger recording all the transactions occurring between parties. They provide a tamper-proof storage featuring public auditability of the data.
By leveraging these characteristics, it is possible to implement an auction protocol relying on smart contracts. Compared to existing schemes, our new generic approach for a first-price auction enables the bidders to stay anonymous while maintaining privacy of the bids. The anonymity is achieved using commitment scheme, public-key encryption and designated identity verifier ring signature, whereas the computation of the winning bid is handled in a zero-knowledge way by a semi-trusted auctioneer.
The scheme is proven to be secure against new security definitions better suited in the context of decentralized auctions. A proof of concept has been implemented using the Ethereum platform and encouraging preliminary results have been computed.”

Dec 09

Seminar: Yves Roggeman “May we trust standard “things”?” (Dec 17, 2019)

Dec 17, 2019 – 13.00 – room P.2NO8.08

Speaker: Yves Roggeman (ULB)

Title: “May we trust standard “things”?”
Short abstract: “Reflections about Hamming weight, standard libraries implementation and object inheritance behavior.”

Dec 03

Seminar: Thibault Debatty “An introduction to similarity search and k-nn graphs” (Dec 03, 2019)

Dec 03, 2019 – 13.00 – room P.2NO8.08

Speaker: Thibault Debatty (Royal Military School)

Title: “An introduction to similarity search and k-nn graphs”
Short abstract: “Similarity search is an essential component of machine learning algorithms. However, performing efficient similarity search can be extremely challenging, especially if the dataset is distributed between multiple computers, and even more if the similarity measure is not a metric. With the rise of Big Data processing, these challenging datasets are actually more and more common. In this presentation, we show how k nearest neighbors (k-nn) graphs can be used to perform similarity search, clustering and anomaly detection.”

Nov 21

Seminar: Gaurav Sharma “Multi-Signatures in Blockchain” (Nov 26, 2019)

Nov 26, 2019 – 13.00 – room P.2NO8.08

Speaker: Gaurav Sharma (ULB)

Title: “Multi-Signatures in Blockchain”
Short abstract: “A multi-signature is a digital signature scheme which allows a group of users to sign a common message. The rogue key attack is the most annoying attack on such signatures. The recent engagement of multi-signatures in blockchain applications is quite appealing. In some particular blockchains, the forward secure multi-signatures are also useful. We study the current state-of-the-art and identify some design goals for secure multi-signatures in plain-public key model.”

Nov 18

Seminar: François Gerard “New parameters and Cortex-M4 optimization for NewHope” (Nov 19, 2019)

Nov 19, 2019 – 13.00 – room P.2NO8.08

Speaker: François Gerard (ULB)

Title: “New parameters and Cortex-M4 optimization for NewHope”

Nov 10

Seminar: Stefano Pironio “Device-independent quantum random number generation” (Nov 12, 2019)

Nov 12, 2019 – 12.30 – room P.2NO8.08

Speaker: Stefano Pironio (ULB)

Title: “Device-independent quantum random number generation”
Short abstract: “By exploiting a feature of quantum theory known as nonlocality, it is possible to design a new kind of quantum random number generator (QRNG) that is qualitatively different from all existing random number generators in that the production of randomness can be certified independently of any assumption about the internal working of the device. This feature is known as “device-independence”. I will explain the basic principles underlying device-independent QRNGs and the current status of their experimental implementation.”

Oct 22

Seminar: Soultana Ellinidou “The networking side of Interconnect” (Oct 29, 2019)

Oct 29, 2019 – 12.30 – room P.2NO8.08

Speaker: Soultana Ellinidou (ULB)

Title: “The networking side of Interconnect”
Short abstract: “Since fifty years, the number of transistors that was able to fit into a single piece of silicon increased in a predictable way known as Moore’s law. This had as a result the digital evolution of minicomputers to PCs, afterwards to smartphones and to cloud, by placing more and more transistors into each generation of their microchip and simultaneously making them more powerful and able to support the dynamic nature of today’s applications (for example in automotives and avionics). However the design and the validation of different architectures have been very well explored in literature, the interconnect fabric connecting the IP blocks of the entire System on Chip (Ship) must be equally explored in order to enable the properly distribution of the data within the system. As SoC grew in numbers of IP blocks, busses and crossbars interconnects revealed their limitations. Hence in the early 2000s, Network on chip (NoC) interconnect introduced as an on-chip packet switching micro-network in order to provide Quality of Service (QoS). Unfortunately due to high structural and functional complexity of NoC, researches start searching alternatives. In this presentation, we will present and evaluate the Software Defined Network on Chip (SDNoC), which is an NoC alternative by focusing on networking, routing and security aspects of it.”

Oct 10

Seminar: Jérémie Roland “Quantum Weak Coin Flipping” (Oct 22, 2019)

Oct 22, 2019 – 13.00 – room P.2NO8.08

Speaker: Jérémie Roland (ULB)

Title: “Quantum Weak Coin Flipping”
Short abstract: “We investigate weak coin flipping, a fundamental cryptographic primitive where two distrustful parties need to remotely establish a shared random bit. A cheating player can try to bias the output bit towards a preferred value. For weak coin flipping the players have known opposite preferred values. A weak coin-flipping protocol has a bias ϵ if neither player can force the outcome towards their preferred value with probability more than 1/2+ϵ. It is known that any classical coin flipping protocol has bias ϵ=1/2, so that practically coin flipping can only be achieved under
computational assumptions. As for quantum protocols, Mochon showed in 2007 [arXiv:0711.4114] that weak coin flipping can be achieved under information-theoretic security with arbitrarily small bias (near
perfectly), but the previously best-known explicit protocol had bias 1/6 (also due to Mochon, 2005 [Phys. Rev. A 72, 022341]). We propose a framework to construct new explicit protocols achieving biases beyond 1/6. In particular, we construct explicit unitaries (quantum operations) for protocols with bias up to 1/10. To go beyond, we introduce an algorithm which, together with the framework, allows us to numerically construct protocols with arbitrarily small biases. This therefore provides a solution
for the problem of quantum weak coin flipping in the absence of noise.”

Oct 04

Seminar: Bojan Spasic “Efficient Symmetric Searchable Encryption for IoT” (Oct 08, 2019)

Oct 08, 2019 – 12.30 – room P.2NO8.08

Speaker: Bojan Spasic (ULB)

Title: “Efficient Symmetric Searchable Encryption for IoT”
Short abstract: “Searchable Symmetric Encryption (SSE) has received a lot of research attention recently. To date, SSE schemes seem to provide the best tradeoff between efficiency and security among different encrypted search solutions (e.g. property-preserving encryption, fully-homomorphic encryption, ORAM, functional encryption). Informally, SSE schemes encrypt a search structure which is outsourced to an untrusted server (e.g. in the cloud) together with the corresponding encrypted data collection.
We propose a dynamic, forward-private searchable symmetric encryption scheme supporting multiple stateless writing clients. Our construction is motivated by the common architecture found in IoT systems consisting of multiple low-power sensor nodes, an outsourced database system and an application client.”