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MAK Crypto Seminar: Ignacio Cascudo

Friday 24 January 2020, at 11. Campus Nord UPC, Building C3, Room 204a (2nd floor).

Friday 24 January 2020, at 11. Campus Nord UPC, Building C3, Room 204a (2nd floor).

Quan
24/01/2020 des de/d' 11:00" (Europe/Madrid / UTC100)
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Campus Nord UPC, Building C3, Room 204a (2nd floor).
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By: Ignacio Cascudo (IMDEA Software, Madrid)

Title: On universally composable secure homomorphic commitment schemes

Abstract: Commitment schemes are the digital equivalent to a safe-box. A committer can put a value in the box (commit), lock it and then send it to a receiver. At a later point the committer can open the commitment (sending the keys to the safe-box). After receiving the box but before receiving the keys, while the receiver cannot see the message, the committer can no longer change it. Commitment schemes are very useful for secure multiparty computation, for which we often want some additional properties: homomorphic properties allow to open some agreed-upon functions of some committed messages; universal composable (UC) security gives strong guarantees of security when commitments are used as a part of larger protocol. In this talk I will describe some highlights of a line of work which constructs UC-secure homomorphic commitments from error-correcting codes and simpler cryptographic primitives.

The talk is based on a series of papers from PKC 2015, Crypto 2016, Asiacrypt 2019 jointly with Ivan Damgård, Bernardo David, Nico Döttling, Rafael Dowsley, Irene Giacomelli, Jesper Buus Nielsen and Roberto Trifiletti.

MAK Crypto Seminar: Ramiro Martínez and Carla Ràfols

Two talks. Friday 29 November 2019, at 10. Campus Nord UPC, Building C3, Room 204a (2nd floor).

Two talks. Friday 29 November 2019, at 10. Campus Nord UPC, Building C3, Room 204a (2nd floor).

Quan
29/11/2019 des de/d' 10:00" (Europe/Madrid / UTC100)
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Campus Nord UPC, Building C3, Room 204a (2nd floor).
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TALK #1:

By: Ramiro Martínez, MAK-UPC

Title: RLWE-based Zero-Knowledge Proofs for linear and multiplicative relations

Abstract: Ring Learning With Errors (RLWE) samples are pairs of polynomials in $\\mathbb{Z}_q\[x\]/(x^{n}+1)$, obtained from a distribution that depends on a secret polynomial. RLWE samples are computationally indistinguishable from uniformly random pairs of polynomials. We present efficient Zero-Knowledge Proofs of Knowledge (ZKPoK) for linear and multiplicative relations among secret messages hidden as RLWE samples. Our proposed protocols for a ZKPoK are based on the celebrated paper by Stern on identification schemes using coding problems (Crypto'93). Our 5-move protocol achieves a soundness error slightly above 1/2 and perfect Zero-Knowledge.

As an application we present ZKPoK of relations between committed messages. The resulting commitment scheme is perfectly binding with overwhelming probability over the choice of the public key, and computationally hiding under the RLWE assumption. Compared with previous Stern-based commitment scheme proofs we decrease computational complexity, improve the size of the parameters and reduce the soundness error of each round.

 

TALK #2:

By: Carla Ràfols, UPF

Title: A survey on SNARKs

Abstract: Zero-Knowledge proofs are among the oldest and most useful cryptographic primitives. Efficient proofs for "simple" languages (non NP complete) have been known for a long time, in different security models and based on various different computational assumptions. SNARKs or Succint Non-Interactive Arguments of Knowledge, proposed by Groth in 2010, allow to prove circuit satisfiability in zero-knowledge. The most efficient constructions are not only succinct (independent of the witness size) but also very efficient concretely. SNARKs have had a major impact in cryptographic research and practice, partly due to their application to anonymous financial transactions in cryptocurrencies. In this talk, I will survey some of the main results, techniques and applications in the area.

MAK Crypto Seminar: Michael Bamiloshin and Victor Peña-Macias

Two talks. Friday 15 November 2019, at 11. Campus Nord UPC, Building C3, Room 204a (2nd floor).

Two talks. Friday 15 November 2019, at 11. Campus Nord UPC, Building C3, Room 204a (2nd floor).

Quan
15/11/2019 des de/d' 11:00" (Europe/Madrid / UTC100)
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Campus Nord UPC, Building C3, Room 204a (2nd floor).
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TALK #1:

By: Michael Olugbenga Bamiloshin, URV Tarragona

Title: Common Information, Matroid Representation, and Secret Sharing for Matroid Ports

Abstract: A secret sharing scheme is a method by which a dealer distributes shares to parties such that only authorized subsets of parties can reconstruct the secret. The information ratio of a secret sharing scheme is the size in bits of the largest share of the scheme divided by the size of the secret. Farràs, Kaced, Martín and Padró presented an improvement in the linear programming technique to derive lower bounds on the information ratio of the schemes for an access structure that use the Ahlswede-Körner lemma and the common information of random variables, avoiding the use of explicit non-Shannon information inequalities (EUROCRYPT 2018). In this work we apply this linear programming technique to the classification of matroids on eight and nine points. Namely, we apply this technique to check if a matroid is multilinearly representable, algebraic or almost entropic. We also present some hitherto unknown non-representable matroids and new bounds on the information ratio of schemes for ports of non-representable matroids.

This is a joint work with Aner Ben-Efraim, Oriol Farràs and Carles Padró.

 

 

TALK #2:

By: Victor Peña-Macias, Universidad Nacional de Colombia

Title: Characteristic-Dependent Linear Rank Inequalities and Applications to Network Coding

Abstract: In Linear Algebra over finite fields, a characteristic-dependent linear rank inequality is a linear inequality that holds by ranks of subspaces of a vector space over a finite field of determined characteristic, and does not in general hold over fields with other characteristic. In this talk, we show a new method to produce these inequalities. We also discuss some results of application to Network Coding, among these, for each finite or co-finite set of primes P, we show that there exists a sequence of networks (N(t)) in which each member is linearly solvable over a field if and only if the characteristic of the field is in P; and the linear capacity, over fields whose characteristic is not in P, tends to 0 as t tends to infinity.

Contextualització de les Matemàtiques (15a sessió) - Matemàiques animades

A càrrec de Josefina Antonijuan Rull i Jordi Guardia Rubies.

A càrrec de Josefina Antonijuan Rull i Jordi Guardia Rubies.

Quan
16/10/2019 de 12:15 a 13:45 (Europe/Madrid / UTC200)
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FME - Aula 005
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Incripció:
https://gcice.upc.edu/fitxa_cursos.asp?id=54476

MAK Crypto Seminar: Chen Yuan and Oriol Farras

Two talks. Thursday 10 October 2019, at 11. Campus Nord UPC, Building C3, Room 204a (2nd floor). 1. Towards Optimal Robust Secret Sharing with Security Against a Rushing Adversary (Chen Yuan) 2. Secret-Sharing Schemes for General Access Structures (Oriol Farras)

Two talks. Thursday 10 October 2019, at 11. Campus Nord UPC, Building C3, Room 204a (2nd floor). 1. Towards Optimal Robust Secret Sharing with Security Against a Rushing Adversary (Chen Yuan) 2. Secret-Sharing Schemes for General Access Structures (Oriol Farras)

Quan
10/10/2019 de 11:00 a 13:00 (Europe/Madrid / UTC200)
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Campus Nord UPC, Building C3, Room 204a (2nd floor)
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Two talks in this session:

 

TALK #1:

By: Chen Yuan, CWI Amsterdam
Title: Towards Optimal Robust Secret Sharing with Security Against a Rushing Adversary

Abstract: Robust secret sharing enables the reconstruction of a secret-shared message in the presence of up to t (out of n) incorrect shares. The most challenging case is when n = 2t + 1, which is the largest t for which the task is still possible, up to a small error probability and with some overhead in the share size. In this work,we propose a new robust secret sharing scheme that offers full security against a rushing adversary. We also answer the open question posed by Cevallos et al.(Eurocrypt 2012) who proposed a scheme with overhead of O(n+K) and asked whether the linear dependency on n was necessary or not.

This is a joint work with Serge Fehr.

 

TALK #2:

By: Oriol Farras, URV Tarragona
Title: Secret-Sharing Schemes for General Access Structures

Abstract: A secret-sharing scheme allows some authorized sets of parties to reconstruct a secret; the collection of authorized sets is called the access structure. For over 30 years, it was known that any (monotone) collection of authorized sets can be realized by a secret-sharing scheme whose shares are of size $2^{n−o(n)}$ and until recently no better scheme was known. In a recent breakthrough, Liu and Vaikuntanathan (STOC 2018) reduced the share size to $O(2^{0.994n})$. We improved the general construction, obtaining a share size $O(2^{0.892n})$. For the special case of linear secret-sharing schemes, we get an exponent of $0.942$ (compared to $0.999$ of Liu and Vaikuntanathan).

This result was included in the paper "Secret-Sharing Schemes for General and Uniform Access Structures", a joint work with Benny Applebaum, Amos Beimel, Oded Nir and Naty Peter presented in Eurocrypt 2019.

Women in Geometry and Topology

Quan
25/09/2019 00:00 a 27/09/2019 23:55 (Europe/Madrid / UTC200)
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Centre de Recerca Matemàtica, Campus de Bellaterra, Edifici C, 08193 Bellaterra (Barcelona)
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Més informació a:

http://www.crm.cat/en/Activities/Curs_2019-2020/Pages/Women-in-Geometry-and-Topology.aspx

Inauguració del curs de GCED. Conferència de Tomàs Molina

Inauguració curs acadèmic 2019-2020 Grau en Ciència i Enginyeria de Dades, dimarts 17 a les 13h, edifici Vèrtex. Lliçó inaugural de Tomàs Molina
Inauguració curs acadèmic 2019-2020 Grau en Ciència i Enginyeria de Dades, dimarts 17 a les 13h, edifici Vèrtex. Lliçó inaugural de Tomàs Molina
Quan
17/09/2019 des de/d' 13:00" (Europe/Madrid / UTC200)
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Edifici Vertex, Campus Nord
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El director de l’ETSETB, Sr. Josep Pegueroles, el degà de la FIB, Sr. Josep Fernández i el degà de la FME, Sr. Jaume Franch, es complauen a convidar-vos a la inauguració del Curs 2019/20 del Grau en Ciència i Enginyeria de Dades, que tindrà lloc el dia 17 de setembre, a les 13h, a l’Auditori de l’edifici Vèrtex del Campus Nord de la UPC (plaça Eusebi Güell, 6 Barcelona).

ORDRE DE L’ACTE

Obre l’acte el  Sr. Josep Pegueroles, director de l’ETSETB.

  • Paraules del Rector de la UPC, Sr. Francesc Torres.
  • Lliçó inaugural: “Com serà el món quan us gradueu” i “Els científics de dades ja pronostiquen el temps”, a càrrec del Sr. Tomàs Molina, Cap de Meteorologia de TV3.
  • Lliurament millor expedient acadèmic de la Fase Inicial del curs 2018/19.
  • Paraules del representant dels estudiants.
  • Cloenda a càrrec del Sr. Josep Pegueroles, director de l’ETSETB

Jornada de Recerca del Departament

El proper 4 de juliol, a la Sala d'Actes de la FME, tindrà lloc la 3a Jornada de Recerca organitzada pel Departament.

El proper 4 de juliol, a la Sala d'Actes de la FME, tindrà lloc la 3a Jornada de Recerca organitzada pel Departament.

Quan
04/07/2019 de 09:35 a 13:10 (Europe/Madrid / UTC200)
On
Sala d'actes de la FME
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Les conferències en aquesta ocasió, estaran a càrrec d'investigadors i investigadores postdoctorals que estan actualment a la UPC: Öznur Yaşar Diner, Gyula Csato, Stefano Pasquali i Juan Margalef. Durant el coffeee break farem una sessió de pòsters.


Més informació sobrel el programa:

https://mat.upc.edu/ca/shared/jornadaderecerca2019.pdf

Jornada de Bones Pràctiques i disseny de cursos ATENEA

ICE inicia un nou cicle de jornades temàtiques dedicades a la millora i ús de la plataforma virtual docent ATENEA. Aquesta Jornada vol incidir en el disseny i gestió de cursos a ATENEA.

ICE inicia un nou cicle de jornades temàtiques dedicades a la millora i ús de la plataforma virtual docent ATENEA. Aquesta Jornada vol incidir en el disseny i gestió de cursos a ATENEA.

Quan
28/06/2019 de 09:30 a 13:00 (Europe/Madrid / UTC200)
On
Campus Sud- UPC (lloc per determinar)
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OBJECTIUS

En aquesta jornada es vol:

  • Presentar una nova eina que permetrà al docent tenir guardats tots els dissenys d’assignatures i coordinacions, desvinculats dels estudiants: El maletí del professor/a.
  • Fer un tastet de dissenys d’assignatures de la UPC a ATENEA de professors de diferents centres i diferents tipologies de cursos per tal de conèixer com es pot gestionar a través d’ATENEA l’activitat del docent en cursos grans, mitjans o petits, per exemple, o com es pot organitzar el material, quines eines d’ATENEA són útils i quines mancances i limitacions es troben en cada cas.
  • Fer un anàlisi i discussió de cap on ha d’evolucionar ATENEA, per tal de poder dedicar esforços en la millora de la plataforma en el sentit correcte.

 

La convocatoria es troba a l'enllaç:

https://gcice.upc.edu/fitxa_cursos.asp?id=54396

Jornada Docent del Departament 2019

4a Jornada Docent del Departament "La perspectiva de gènere en la pràctica de les Matemàtiques"

4a Jornada Docent del Departament "La perspectiva de gènere en la pràctica de les Matemàtiques"

Quan
26/06/2019 de 09:45 a 13:45 (Europe/Madrid / UTC200)
On
Sala d’actes de la Facultat de Matemàtiques i Estadística
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M. Alsina, A. Carmona, A. Encinas, J. Guàrdia, C. Pantazi
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El dimecres 26 de juny tindrà lloc la 4a Jornada Docent del Departament, amb el títol "La perspectiva de gènere en la pràctica de les Matemàtiques".  Hi haurà dues conferències plenàries, a càrrec de C. Grima (U. Sevilla) i A. Susín i dos tallers (J. Saludes i F. Aguiló).

La Jornada compta amb el suport de la Facultat de Matemàtiques i Estadística i de l'Institut de Ciències de l'Educació.

Programa

Podeu inscriure-us a l'enllaç:

https://gcice.upc.edu/fitxa_cursos.asp?id=54398