Category: QualSec seminars

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.”

Sep 13

Seminar: Yann Barsamian “Algorithms + Data Structures = Efficient Particle Simulations” (Sep 24, 2019)

Sep 24, 2019 – 12.30 – room FORUM H

Speaker: Yann Barsamian (ULB)

Title: “Algorithms + Data Structures = Efficient Particle Simulations”
Short abstract: “Particle simulations are widely used in different contexts where computer simulations are needed, e.g., plasma physics, astrophysics. In this talk, we will restrict to the case where we simulate N particles on a discretized 3d grid, with the Particle-in-Cell (PIC) method: at each step of the simulation, we have O(N) computations.

Because of the required values for N and the grid size, we need to write efficient programs and use supercomputers — thousands of cores or more. In this talk, we will focus on super-computers where each node consists of multi-core processors. We will show how to reach 55% of the peak performance on these processors, measured in the roofline model. We will detail the data structure for the particles and the fields as well as the algorithm to update the particles. We will finally present a metric to compare the performance of different Particle-in-Cell implementations on different computer architectures.”

Feb 04

Seminar: François-Xavier Standaert, “Towards Physically-Secure Implementations & the Need of Theory, Practice and Open Designs” (Feb 28, 2019)

Feb 28, 2019 – 13.00 – room P.2NO5 Solvay Room

Speaker: François-Xavier Standaert (UCL)

Title: “Towards Physically-Secure Implementations & the Need of Theory, Practice and Open Designs”

Abstract: In this talk, I will survey recent approaches/results to obtain physical security against side-channel attacks exploiting leakages, such as an implementation’s power consumption. After a brief introduction and motivation, I’ll describe how these attacks proceed (i.e., the so-called standard DPA setting) and why purely hardware-level (practical, heuristic) countermeasures alone cannot solve the problem. I will then discuss how the impact of hardware-level countermeasures can be amplified thanks an algorithmic-level countermeasure called masking, how this amplification can be formally analyzed, and the implementation challenges that physical defaults can imply for the secure implementation of masking. I will conclude by discussing the need of an open approach to physical security, and the interest of re-designing cryptographic algorithms and protocols for this purpose.

Dec 11

Seminar: Rajeev Anand Sahu “Strong Designated Verifier Signcryption” (Dec 12, 2018)

Dec 12, 2018 – 13.00 – room P.2NO8.08

Speaker: Rajeev Anand Sahu (ULB)

Title: “Strong Designated Verifier Signcryption”
Short abstract: “Recall two important cryptographic primitives: Strong designated verifier signature
(SDVS), which can be verified only by the designated receiver, and Signcryption, which is a hybrid cryptographic primitive that offers functionality of both digital signature and encryption in a single phase. Signcryption is useful for electronic transactions where authentication and privacy both are desired together, for example in secure routing, multi-cast key distribution etc. However, in a usual SDVS, the message is always sent with the signature, which is not desired for classified messages. Instead, to ensure the confidentiality of the message an encryption can be used. On the other hand in a signcryption scheme a designated authentication may require for special needs. To address this issue, we combine these two primitives SDVS and Signcryption, and propose a condensed construction of strong designated verifier signcryption (SDVSigncryption) scheme. The protocol enjoys all properties of the individual primitives. The scheme uses functionalities of bilinear pairing and has been designed on the identity-based setting to avoid key management overhead. Security of the scheme has been realized over the standard assumption, the hardness of computational bilinear Diffie-Hellman problem (CBDHP).”

Dec 03

Seminar: Gaurav Sharma “Security Threats on NoC-based MPSoCs” (Dec 05, 2018)

Dec 05, 2018 – 13.00 – room P.2NO8.08

Speaker: Gaurav Sharma (ULB)

Title: “Security Threats on NoC-based MPSoCs”
Short abstract: “The target applications are spread on a multi-processor system-on-chip (MPSoC) platform to enhance performance. The peer interaction of IP cores invite several security vulnerabilities. Our investigation is mainly focused on isolating computation and communication resources for sensitive applications. A relative study of existing approaches is presented during this talk. Furthermore, we analyze how software defined networking (SDN) approach can be a viable solution to ensure security in such systems.”

Nov 19

Seminar: Suman Bala “Searching over Encrypted Emails” (Nov 21, 2018)

Nov 21, 2018 – 13.00 – room P.2NO8.08

Speaker: Suman Bala (ULB)

Title: “Searching over Encrypted Emails”
Short abstract: “Searching over outsourced encrypted data is challenging while preserving realistic communication, computation and storage overhead. E-mail encryption has been a long-standing issue of usable security. The users, who archive email messages in outsourced storage will not only wants to hide the contents of the archived messages from anyone especially the server but also wants to search over them if the need arises. Various solutions will be addressed for their adoption and usability in the case of email system.”

Nov 12

Seminar: Ankan Pal “Mathematics of Post-Quantum Cryptography” (Nov 22, 2018)

Nov 22, 2018 – 11.00 – room P.2NO8.08

Speaker: Ankan Pal (University of L’Aquila)

Title: “Mathematics of Post-Quantum Cryptography”
Short abstract: “Since the last decade, the Post-Quantum (PQ) Cryptography has drawn attention of researchers due to its resistance against the upcoming quantum threats. As the security of many classical and popular cryptosystems are based on the intractability of the underlying hard mathematical problems, in a permissible amount of time, it is of worth interest to investigate the difficulty of solution of those problems in classical era versus quantum era. This talk also aims to explore distinguished mathematical properties which support cryptographic primitives as candidate post-quantum cryptosystems, for example Isogeny-Based Elliptic Curve Cryptography, Lattice-Based Cryptography. Lastly, this talk intend to address some methods from Algebraic Geometry to attack ECDLP.”

Nov 12

Seminar: Soultana Ellinidou “SDNoC: A new NoC alternative” (Nov 14, 2018)

Nov 14, 2018 – 13.00 – room P.2NO8.08

Speaker: Soultana Ellinidou (ULB)

Title: “SDNoC: A new NoC alternative”
Short abstract: “As the number of processors and cores on a single chip is increasingly dramatically, the communication among them is of bigger concern. SDNoC is a NoC alternative able to solve the scalability issues by bringing Software Defined Network approach within Hardware. However it also brought a lot of new threats into hardware.”

Nov 05

Seminar: Helena Bruyninckx “Quantum Key Recycling Scheme based on qubits” (Nov 7, 2018)

Nov 7, 2018 – 13.00 – room P.2NO8.08

Speaker: Helena Bruyninckx (ULB)

Title: “Quantum Key Recycling Scheme based on qubits”
Short abstract: “Quantum Key Recycling Schemes encode information into quantum states, such that the detection of eavesdropping is made possible. In case no eavesdropping was detected, the secret shared key can be safely re-used which is impossible for classical encryption schemes like the one-time pad. In this talk, we discuss a Quantum Key Recycling Scheme for classical messages and compare it to previous schemes.”