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Hello! My name is João and I am a PhD student in the Department of Computing at Imperial College London, advised by Mahdi Cheraghchi. Recently, I have also been spending some time at CQT (hosted by Divesh Aggarwal) and UIUC (hosted by Olgica Milenkovic).

Background: I hold an MSc in Computer Science from ETH Zurich and a BSc in Applied Mathematics and Computation from Instituto Superior Técnico. 

You can find my detailed CV here.

Research interests: Broadly speaking, I like coding theory, cryptography, information theory, and theoretical computer science.

Teaching: I was/am a teaching assistant for the following courses
Contact: j.lourenco-ribeiro17 (at) imperial (dot) ac (dot) uk


Work

Extractor lower bounds, revisited, with Divesh Aggarwal, Siyao Guo, Maciej Obremski, and Noah Stephens-Davidowitz.
Manuscript, 2019.

An overview of capacity results for synchronization channels, with Mahdi Cheraghchi.
Manuscript (survey), 2019.

How to extract useful randomness from unreliable sources, with Divesh Aggarwal, Maciej Obremski, Luisa Siniscalchi, and Ivan Visconti.
Manuscript, 2019.

Coded trace reconstruction, with Mahdi Cheraghchi, Ryan Gabrys, and Olgica Milenkovic.
ITW 2019.

Stronger leakage-resilient and non-malleable secret-sharing schemes for general access structures, with Divesh Aggarwal, Ivan Damgård, Jesper Buus Nielsen, Maciej Obremski, Erick Purwanto, and Mark Simkin.
CRYPTO 2019.

Simple codes and sparse recovery with fast decoding, with Mahdi Cheraghchi.
ISIT 2019.

Information-theoretic secret-key agreement: The asymptotically tight relation between the secret-key rate and the channel quality ratio, with Daniel Jost and Ueli Maurer.
TCC 2018.

Sharp analytical capacity upper bounds for sticky and related channels, with Mahdi Cheraghchi.
Conference version: Allerton 2018.
Journal version: IEEE Transactions on Information Theory, 2019.

Improved upper bounds and structural results on the capacity of the discrete-time Poisson channel, with Mahdi Cheraghchi.
Conference version: ISIT 2018.
Journal version: IEEE Transactions on Information Theory, 2019.

New perspectives on weak oblivious transfer, with Ueli Maurer.
ISIT 2016.

Quantum blind signature with an offline repository, with Paulo Mateus and André Souto.
International Journal of Quantum Information, 2015.


Recorded talks

Coded and uncoded trace reconstruction.
Invited talk at the Shannon Channel, hosted by Salim El Rouayheb.


Theses

Challenges in information-theoretic secret-key agreement. MSc thesis at ETH Zurich supervised by Daniel Jost and Ueli Maurer, 2017. 
Awarded the ETH Medal for outstanding MSc theses