This week we had two visitors in our Tokyo Tech lab, which we nicknamed “Covfefe”. Rafael Dowsley came from Denmark and Christian Lindgren came from Osaka.

CNPQ

less than 1 minute read

Published: October 10, 2018

In Japan but thinking about the future of Brazil.

World Economic Forum

less than 1 minute read

Published: September 18, 2018

Cryptography meets economy.

It was a great chance to travel to China to attend the World Economic Forum during the Annual Meeting of the New Champions in Tianjin.

portfolio

Thoughts on digital money, cryptography and career

Published: June 25, 2016

Some thoughts on digital cash, personal interest on cryptography, and research in Japan

Royale, Kaleidoscope and 21

Published: January 01, 2018

Detailed video explaining our card game protocols in IOHK 2018 Summit in Portugal.

Account Management and Stake Pools Crypto Rump Session

Published: August 15, 2018

My presentation on our work on Stake Pools during Rump Session at Crypto 2018.

Interview: Cardano Effect

Published: October 01, 2019

Interview I gave for Cardano Effect about provable security.

Interview: University of Pelotas

Published: June 21, 2020

I had a chat with my colleague and friend Prof. Ricardo Araujo.

Talk: Pre-recorded video for SCN 2020

Published: September 14, 2020

SCN’ 20 Pre-recorded video.

Talk: Pre-recorded video for CANS 2020

Published: December 15, 2020

CANS’ 20 Pre-recorded video.

Talk: Pre-recorded video for FC 2021

Published: March 05, 2021

FC’ 21 Pre-recorded video.

Talk: Pre-recorded video for ACNS 2021

Published: June 21, 2021

ACNS’ 21 Pre-recorded video.

publications

Programmability in GGM

Published in ProvSec, 2011

We explore the idea of introducing programmability in generic models.

Recommended citation: Mario Larangeira and Keisuke Tanaka. (2011). " Programmability in the Generic Ring and Group Models." ProvSec 2011. http://isyou.info/jisis/vol1/no23/jisis-2011-vol1-no23-05.pdf

Non-programmable Security Proof for FDH

Published in WISA, 2012

A security analysis on the non-programmable Random Oracle Model

Recommended citation: Mario Larangeira and Keisuke Tanaka. (2012). " Reduction-Centric Non-programmable Security Proof for the Full Domain Hash in the Random Oracle Model." WISA 2012. https://link.springer.com/chapter/10.1007/978-3-642-35416-8_10

CryptoNoteに対するサイズ効率化

Published in SCIS, 2017

In this paper, we define a VDF variant, which we denote by verifiable sequential work (VSW)

Recommended citation: 原　啓祐, Mario Larangeira、圭介田中. (2017). " CryptoNoteに対するサイズ効率化." SCIS 2017. https://www.iwsec.org/scis/2017/program.html

カレイドスコープとロイヤーレ：ポーカーと一般的なカードゲームのブロックチェーンのプロトコル

Published in SCIS, 2018

Here we review Kaleidoscope and Royale two protocols for card games over blockchains.

Recommended citation: マリオラランジェラ、ベルナルドデヴィッド、ラファエルドスレイ. (2018). " カレイドスコープとロイヤーレ：ポーカーと一般的なカードゲームのブロックチェーンのプロトコル." SCIS 2018. https://www.iwsec.org/scis/2018/program.html

Bringing down the complexity

Published in ACISP, 2018

This work identifies a new class of card games which allow us to developed highly efficient card game protocols.

Recommended citation: Bernardo David, Rafael Dowsley and Mario Larangeira. (2018). " 21 - Bringing Down the Complexity: Fast Composable Protocols for Card Games Without Secret State." ACISP 2018. https://eprint.iacr.org/2018/303

MARS

Published in Cryblock, 2018

A blockchain based incentive framework for routing systems.

Recommended citation: Bernardo David, Rafael Dowsley and Mario Larangeira. (2018). " MARS: Monetized Ad-Hoc Routing Systems." Cryblock. https://dl.acm.org/doi/abs/10.1145/3211933.3211948?download=true

Kaleidoscope

Published in Financial Cryptography, 2018

An efficient blockchain based protocol for poker.

Recommended citation: Bernardo David, Rafael Dowsley and Mario Larangeira. (2018). " Kaleidoscope: An Efficient Poker Protocol with Payment Distribution and Penalty Enforcement." FC 2018. https://eprint.iacr.org/2017/899

Verifiable Sequential Work with Trusted Generator

Published in SCIS, 2019

In this paper, we define a VDF variant, which we denote by verifiable sequential work (VSW)

Recommended citation: Xiangyu Su, Mario Larangeira and Keisuke Tanaka. (2019). " Verifiable Sequential Work with Trusted Generator." SCIS 2019. https://www.iwsec.org/scis/2019/program.html

Notes on Offchain Protocols

Published in SCIS, 2019

A survey on off-chain protocol ranging from payment channels, to routing, commit chains, and etc.

Recommended citation: Maim Jourenko, Kanta Kurazumi, Mario Larangeira and Keisuke Tanaka. (2019). " Notes on Offchain Protocols." SCIS 2019. https://www.iwsec.org/scis/2019/program.html

Lightweight Virtual Payment Channels

Published in SCIS, 2019

A lighweight Virtual Payment Protocols which can be implemented on Bitcoin

Recommended citation: Maxim Jourenko, Keisuke Tanaka and Mario Larangeira. (2019). "Lightweight Virtual Payment Channels." SCIS 2019. https://www.iwsec.org/scis/2019/program.html

A Timeout Anonymous Payment Channel for Decentralized Currencies

Published in SCIS, 2019

A variant of the Anonymous payment channel (APC) definition which includes a time-out parameter.

Recommended citation: Kanta Kurazumi, Maxim Jourenko, Mario Larangeira, and Keisuke Tanaka. (2019). " A Timeout Anonymous Payment Channel for Decentralized Currencies." SCIS 2019. https://www.iwsec.org/scis/2019/program.html

Account Management and Stake Pools in Proof of Stake Ledgers

Published in SCIS, 2019

A foundational work on the definition of accounts and stake pools in Proof-of-stake based ledgers.

Recommended citation: Dimitris Karakosstas, Aggelos Kiayias, Mario Larangeira. (2019). " Account Management and Stake Pools in Proof of Stake Ledgers." SCIS 2019. https://www.iwsec.org/scis/2019/program.html

Royale

Published in Financial Cryptography, 2019

A general and universally composable protocol for card games on blockchain.

Recommended citation: Bernardo David, Rafael Dowsley and Mario Larangeira. (2019). " Royale: A Framework for Universally Composable Card Games with Financial Rewards and Penalties Enforcement." FC 2019. https://eprint.iacr.org/2018/157

Account Management in PoS

Published in 12th Conference on Security and Cryptography for Networks, 2020

Security of wallets in proof-of-stake setting in the presence of stake pools.

Recommended citation: Dimitris Karakostas, Aggelos Kiayias and Mario Larangeira. (2020). " Account Management in Proof of Stake Ledgers." SCN 2020. https://eprint.iacr.org/2020/525

Lightweight Virtual Channels in CANS 2020

Published in 19th International Conference on Cryptology and Network Security, 2020

Virtual Channels are now available on Bitcoin!

Recommended citation: Maxim Jourenko, Mario Larangeira and Keisuke Tanaka. (2020). "Lightweight Virtual Payment Channels." CANS 2020. https://eprint.iacr.org/2020/998

ICBC 2021

Published in IEEE International Conference on Blockchain and Cryptocurrency, 2021

Proof of Work with Time and Memory

Recommended citation: Xiangyu Su, Mario Larangeira and Keisuke Tanaka. (2021). "How to Prove Work: With Time or Memory." ICBC IEEE 2021. https://icbc2021.ieee-icbc.org/

Payment Trees in FC 2021

Published in 25th Financial Cryptography and Data Security, 2021

Payment Trees: Settlement of Channels

Recommended citation: Maxim Jourenko, Mario Larangeira and Keisuke Tanaka. (2021). "Payment Trees: Low Collateral Payments for Payment Channel Networks." FC 2021. https://eprint.iacr.org/2020/1313

‘WOTS up my sleeve!’ on ACNS 2021

Published in 19th International Conference on Applied Cryptography and Network Security, 2021

WOTS up my Sleeve! A hidden trick!

Recommended citation: David Chaum, Mario Larangeira, Mario Yaksetig and William Carter. (2021). "WOTS+ up my Sleeve! A Hidden Secure Fallback for Cryptocurrency Wallets." ACNS 2021. http://sulab-sever.u-aizu.ac.jp/ACNS2021/

Hot/Cold Wallet in SECRYPT 2022

Published in 20th International Conference on Security and Cryptography, 2022

A novel way to approach Hot/Wold Wallet

Recommended citation: Rafael Dowsley, Mylene C. Q. Farias, Mario Larangeira, Anderson Nascimento and Jot Virdee. (2022). "A Spendable Cold Wallet from QR Video." SECRYPT 2022. https://secrypt.scitevents.org/

‘Tweakable Sleeve’ on MARBLE 2022

Published in 3rd International Conference on Mathematical Research for Blockchain Economy, 2022

Sleeve 2! A Tweakable Sleeve

Recommended citation: David Chaum, Mario Larangeira and Mario Yaksetig. (2022). "Tweakable Sleeve: A Novel Sleeve Construction based on Tweakable Hash Functions." MARBLE 2022. https://www.marble-conference.org/marble2022

‘Interhead Hydra’ on MARBLE 2022

Published in 3rd International Conference on Mathematical Research for Blockchain Economy, 2022

Interhead Hydra: Two Heads are better than one!

Recommended citation: Maxim Jourenko, Mario Larangeira and Keisuke Tanaka. (2022). "Interhead Hydra: Two Heads are Better than One." MARBLE 2022. https://www.marble-conference.org/marble2022

‘Reputation at Stake!’ on ICISC 2022

Published in 25th Annual International Conference on Information Security and Cryptology, 2022

Reputation at Stake!

Recommended citation: Mario Larangeira. (2022). "Reputation at Stake! A Trust Layer overDecentralized Ledger for Multiparty Computation and Reputation-Fair Lottery." ICISC 2022. http://www.icisc.org/mainp

‘WOTSwana: The generalization of Sleeve’ on ICISC 2022

Published in 25th Annual International Conference on Information Security and Cryptology, 2022

Reputation at Stake!

‘State Machines across Isomorphic Layer 2 Ledgers’ on FC 2023

Published in 27th International Conference Financial Cryptography and Data Security, 2022

Better State Machines for Interheads

Recommended citation: Maxim Jourenko and Mario Larangeira. (2023). "State Machines across Isomorphic Layer 2 Ledgers." FC 2023. https://fc23.ifca.ai/

‘Maravedí: A Secure and Practical Protocol to Trade Risk for Instantaneous Finality’ on AFRICACRYPT 2023

Published in 14th International Conference on Cryptology AFRICACRYPT 2023, 2023

A new way of implementing finality.

Recommended citation: Maxim Jourenko and Mario Larangeira. (2023). "Maravedí: A Secure and Practical Protocol to Trade Risk for Instantaneous Finality." AFRICACRYPT 2023. https://africacrypt2023.tn/

‘Provably Secure Blockchain Protocols from Distributed Proof-of-Deep-Learning’ in NSS’23

Published in 17th International Conference on Network and System Security, 2023

Harvesting computational power for deep learning

Recommended citation: Xiangyu Su, Mario Larangeira and Keisuke Tanaka. (2023). "Provably Secure Blockchain Protocols from Distributed Proof-of-Deep-Learning." NSS 2023.

talks

IOHK/Tokyo Tech Workshop

Published: June 26, 2018

Visit to Pelotas Federal University (UFPel)

Published: September 07, 2018

人間機械協奏技術コンソーシアム第6回公開シンポジウム

Published: January 08, 2019

Presentation: “Overview of Blockchain Technology and Collaboration between Tokyo Tech and Industry”

Binance Blockchain Event

Published: January 22, 2019

SCIS 2019

Published: January 25, 2019

We have presented our current work at SCIS 2019.

IOHK Summit- History of Mental Poker Research

Published: April 15, 2019

Visit to University of Washington

Published: April 20, 2019

Cardano IOHK Virtual Summit

Published: July 03, 2020

Times of COVID! This month we had our yearly summit! And It was a virtual one!

Seminar UFPel on Cryptography and Blockchain

Published: July 21, 2020

Seminar on Blockchain research at UFPel

Lightweight Virtual Channels in CANS 2020

Published: December 15, 2020

Lightweight Virtual Channels!

Payment Trees in FC 2021

Published: March 05, 2021

Payment Trees!

Research Summit in Edinburgh

Published: September 16, 2022

During the week of November 14-20 the whole Research Division of Input Output met at the University of Edinburgh.

Panel at Brazilian Embassy in Tokyo

Published: December 02, 2022

December, 2nd 2022 the Second Meeting of the Brazilian Diaspora in Science and Innovation happened at the Brazilian Embassy in Tokyo. I had the chance to join a panel to discuss the current situation of researchers in Japan.

SCIS 2023 in Kokura

Published: January 24, 2023

During January 24-27 the SCIS 2023 happened in Kokura and our group had four presentations. They were

Talk show about study in Japan at Kyodai Remittance

Published: February 08, 2023

Me and Eunice joined a talk show organized by Antonio from the Kyodai Remittance, with the head of the Consulate General of Brazil in Tokyo Guilherme Patriota, Tiago BonTempo, Taís Ueta, Rodrigo Fernandes and Rafaela Yoshiy about studying and building a career in Japan.

Maravedí at Africacrypt 2023

Published: July 19, 2023

During a week in July I attended Africacrypt 2023 in Tunisia. I have presented the Maravedí Protocol which is a joint work with Maxim Jourenko and shows a novel way to think finality.

NSS’2023

Published: August 14, 2023

This week the International Conference on Network and System Security (NSS’23) happens and we have our work on distributed deep learning in the program. It is a joint work of me, Xiangyu Su and Keisuke Tanaka. Su is the main author and has introduced the main idea.

Su noticed that it is possible to harvest of a computational power from, say, of a proof of work protocol, in order to train models for machine learning. In order to do that we had to introduce new notions like “distributed proof-of-deep-learning”.

Basically, instead of “correct hash value” as in proof-of-work, the system trains models up until a certain suitable accuracy level in the learning curve. The paper is already available here and here. Please take a look.

Mario Larangeira, Ph.D.

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