Estuardo Alpirez Bock

My name is Estuardo and I am a cryptographer at Xiphera in Finland, where we design and implement cryptographic solutions in hardware. I received my PhD at Aalto University under the supervision of Chris Brzuska, co-advised by Wil Michiels. During my PhD, I worked on definitional studies and feasibility results for white-box cryptography, as well as on the design of automated attacks on white-box cryptographic implementations. Later, I held different research positions at Aalto and Radboud University, working on hardware security as well as side-channel analysis of lattice-based crypto candidates. In earlier years, I was an employee at the Leibniz Institute for High Performance Microelectronics IHP, where I worked on the design and implementation of hardware accelerators for elliptic curve cryptography in the light of side channel analysis attacks.

I've always been curious about the challenges that come up when cryptography is implemented in the real world.

Below you will find a list of my publications and further research activities from recent years.

Publications

Adaptive Distributional Security for Garbling Schemes with O(|x|) online complexity with Chris Brzuska, Pihla Karanko, Sabine Oechsner and Kirthivaasan Puniamurthy
ASIACRYPT 2023

On Provable White-Box Security in the Strong Incompressibility Model with Chris Brzuska and Russell W. F. Lai
TCHES 2023 [Slides] [YouTube]

(preprint) Breaking DPA-protected Kyber via the pair-pointwise multiplication with Gustavo Banegas, Chris Brzuska, Lukasz Chmielewski, Kirthivaasan Puniamurthy and Milan Šorf

Protecting the most significant bits in scalar multiplication algorithms with Lukasz Chmielewski and Konstantina Miteloudi
SPACE 2022 [Slides]

White-box cryptography with global device-binding from message recoverable signatures and token-based obfuscation with Shashank Agrawal, Yilei Chen and Gaven Watson
COSADE 2023 [Slides]

Security Reductions for White-Box Key-Storage in Mobile Payments with Chris Brzuska, Marc Fischlin, Christian Janson and Wil Michiels
ASIACRYPT 2020 [Slides] [YouTube]

Security Assessment of White-Box Design Submissions of the CHES 2017 CTF Challenge with Alexander Treff
COSADE 2020 [Slides]

On the Security Goals of White-Box Cryptography with Alessandro Amadori, Chris Brzuska and Wil Michiels
TCHES 2020 [Slides] [YouTube]

White-Box Cryptography: Don't Forget About Grey Box Attacks with Joppe W. Bos, Chris Brzuska, Charles Hubain, Wil Michiels, Cristofaro Mune, Eloi Sanfelix Gonzalez, Philippe Teuwen and Alexander Treff
Journal of Cryptology 2019

Doubly half-injective PRGs for incompressible white-box cryptography with Alessandro Amadori, Joppe W. Bos, Chris Brzuska and Wil Michiels
CT-RSA 2019 [Slides]

On the Ineffectiveness of Internal Encodings - Revisiting the DCA Attack on White-Box Cryptography with Chris Brzuska, Wil Michiels and Alexander Treff
ACNS 2018 [Slides] [YouTube]

Increasing the Robustness of the Montgomery kP-Algorithm against SCA by Modifying its Initialization with Zoya Dyka and Peter Langendoerfer
SECITC 2016 [Slides]

Inherent Resistance of Efficient ECC Designs against SCA Attacks with Zoya Dyka, Ievgen Kabin and Peter Langendoerfer
NTMS 2016

Visits and Internships

Visa Research in Palo Alto, California
3 month internship under the supervission of Gaven Watson and in collaboration with Shashank Agrawal and Yilei Chen
February - May 2020

TU Eindhoven, Netherlands
Research visit to Wil Michiels and Alessandro Amadori at the department of Mathematics and Computer Science and Embedded Networked Systems at Eindhoven University of Technology
January - March 2017