[crypto] Fwd: CWG: 20 March Programme

[R. Hirschfeld]

-------- Original Message --------
Subject: CWG: 20 March Programme
Date: 2026-03-16 15:48
 From: "Guarise Vieira, Heloise" <h.guarise.vieira at tue.nl>
To:

Dear Crypto Working Group participant,

Find below the schedule for our next meeting.
We will see you this Friday, 20 March from 10:45h to 15:45h, at the 
Kargadoor, in Utrecht.

Best regards,

---------------------------

10:45
Key management in cloud environments
Jurjen Bos

In this presentation, I'll give you an inside peek of the banking 
position towards cryptography. I'll explain how the current trend of 
moving applications to the cloud makes it harder to maintain 
cryptographic security. Finally, I describe a research project of myself 
where I try to find a way to get cryptography to the cloud without 
compromising security.

11:30 – Coffee Break

11:45h
Protoss Protocol for Tight Optimal Symmetric Security
Emanuelle di GIandomenico

We present Protoss, a new balanced PAKE protocol with optimal 
communication efficiency. Messages are only 160 bits long, and the 
computational complexity is lower than all previous approaches. Our 
protocol is proven secure in the random oracle model and features a 
security proof in a strong security model with multiple parties and 
multiple sessions, while allowing for generous attack queries including 
multiple Test-queries. Moreover, the proof is in the practically 
relevant single-bit model (that is harder to achieve than the 
multiple-bit model) and tightly reduces to the Strong Square 
Diffie-Hellman assumption (SSQRDH). This allows for very efficient, 
theoretically sound instantiations and tight compositions with symmetric 
primitives.


12:30h – Lunch

14:00h

Smoothing the degree of regularity for polynomial systems
Melvin Seitner


The eXtended Linearization (XL) algorithm is an algebraic method for 
solving systems of polynomials in multiple variables. It achieves this 
by taking elements of such a system, up to some degree, and transforming 
them into linear restrictions. Said degree must be high enough that the 
resulting linear system is overdetermined, and has a major impact on the 
runtime of the algorithm.
However, this degree is a rather coarse parameter. This leads to cases 
where XL uses excessively overdetermined systems, because the system for 
one degree lower is only slightly underdetermined. To reduce this 
coarseness, we propose a generalisation of XL, which allows for 
intermediate options between the integer values of the degree.

14:45h – Coffee Break

15:00h

How not to do ARIMAX predictions in FHE
Stefan van den Berg

To prepare for the next pandemic we attempt to replay the previous 
pandemic. During the replay we want to perform analysis to predict the 
number of COVID-19 infections. For this prediction we use ARIMAX. 
However, we don’t want to bundle all the data at a single party in plain 
text. Therefore, we use FHE to run the analysis. Certain decisions were 
not ideal, but we did learn from them.

15:45h – End of activities
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[Image]

Heloise Vieira, PhD
Discrete Mathematics Cluster, Project Leader
RSO, Program expert in Defense, Security, and Resilience
+31 (0)402474864
MetaForum, MF 5.120