Tung Chou

I am currently an assistant research fellow at Research Center for Information Technology Innovation, Academia Sinica, Taiwan.

Before (Feb. 2017--Nov. 2019) I was a specially appointed assistant professor at Osaka University, Japan.
Before (Sep. 2016--Jan. 2017) I was a postdoctoral researcher at the Cryptographic Implementations group at Technische Universiteit Eindhoven, the Netherlands.
Before (Sep. 2012--Aug. 2016) I was a PhD student at the Cryptographic Implementations group at Technische Universiteit Eindhoven, the Netherlands.
My advisors were Daniel J. Bernstein and Tanja Lange.

Before I was a research assistant at Institute of Information Science, Academia Sinica, Taiwan, under supervision of 楊柏因 (Bo-Yin Yang).
Before I was a master student at the Department of Electrical Engineering of National Taiwan University, Taiwan, under supervision of 鄭振牟 (Chen-Mou Cheng).

Info

Email: blueprint at crypto dot tw
Google scholar page

Achievements

I designed a way to reduce the signature size of the LESS post-quantum signature scheme, by a large factor; see the preprint.

I am one of the authors of MEDS, a post-quantum signature scheme that has been submitted to NISTPQC. I designed 2 algebraic modellings for the underlying hard problem; see the paragraph "improved modelling" of the corresponding paper. I also designed a way to reduce the signature size by a large factor; see Section 8 of the specification.

I am one of the authors of Classic McEliece, a post-quantum key encapsulation mechanism (KEM). The scheme has been recommended by BSI for long-term confidentiality and is currently one of the few candidates in the 4th round of NISTPQC. I am the main programmer of the 4 official software implementations of the scheme. I am also the one who designed the 5 'f' parameter sets, which allow faster key generation than other parameter sets.

Preprints

On Linear Equivalence, Canonical Forms, and Digital Signatures.
Tung Chou, Edoardo Persichetti, Paolo Santini. 2023. [pdf]

CryptAttackTester: formalizing attack analyses.
Daniel J. Bernstein, Tung Chou. 2023. [pdf]

Journal papers

A Constant-time AVX2 implementation of a variant of ROLLO.
Tung Chou, Jin-Han Liou. TCHES 2022. [pdf]

Complete and improved FPGA implementation of Classic McEliece.
Po-Jen Chen, Tung Chou, Sanjay Deshpande, Norman Lahr, Ruben Niederhagen, Jakub Szefer, Wen Wang. TCHES 2022. [pdf]

Rainbow on Cortex-M4.
Tung Chou, Matthias J. Kannwischer, Bo-Yin Yang. TCHES 2021. [pdf]

CTIDH: faster constant-time CSIDH.
Gustavo Banegas, Daniel J. Bernstein, Fabio Campos, Tung Chou, Tanja Lange, Michael Meyer, Benjamin Smith, Jana Sotáková. TCHES 2021. [pdf]

Optimizing BIKE for the Intel Haswell and ARM Cortex-M4.
Ming-Shing Chen, Tung Chou, Markus Krausz. TCHES 2021. [pdf]

Classic McEliece on the ARM Cortex-M4.
Ming-Shing Chen, Tung Chou. TCHES 2021. [pdf]

McBits revisited: toward a fast constant-time code-based KEM.
Tung Chou. J. Cryptographic Engineering, 2018.

Conference papers

Reducing signature size of matrix-code-based signature schemes.
Tung Chou, Ruben Niederhagen, Lars Ran, Simona Samardjiska. PQCrypto 2024 (to appear).

Take your MEDS: digital signatures from matrix code equivalence.
Tung Chou, Ruben Niederhagen, Edoardo Persichetti, Tovohery Hajatiana Randrianarisoa, Krijn Reijnders, Simona Samardjiska, Monika Trimoska. Africacrypt 2023. [pdf]

An IND-CCA2 attack against the 1st- and 2nd-round versions of NTS-KEM.
Tung Chou. SecITC 2020. [pdf]

A closer Look at the Guo-Johansson-Stankovski attack against QC-MDPC codes.
Tung Chou, Yohei Maezawa, Atsuko Miyaji. ICISC 2018. [pdf]

McBits revisited.
Tung Chou. CHES 2017. [pdf]

QcBits: constant-time small-key code-based cryptography.
Tung Chou. CHES 2016. [pdf]

How to manipulate curve standards: a white paper for the black hat.
Daniel J. Bernstein, Tung Chou, Chitchanok Chuengsatiansup, Andreas Hülsing, Tanja Lange, Ruben Niederhagen, Christine van Vredendaal. SSR 2015. [pdf]

Sandy2x: new Curve25519 speed records.
Tung Chou. SAC 2015. [pdf].

The simplest protocol for oblivious transfer.
Tung Chou, Claudio Orlandi. Latincrypt 2015. [pdf]

Faster binary-field multiplication and faster binary-field MACs.
Daniel J. Bernstein, Tung Chou. SAC 2014. [pdf]

McBits: fast constant-time code-based cryptography.
Daniel J. Bernstein, Tung Chou, Peter Schwabe. CHES 2013. [pdf]

Fast exhaustive search for quadratic systems in F₂ on FPGAs.
Charles Bouillaguet, Chen-Mou Cheng, Tung Chou, Ruben Niederhagen, Bo-Yin Yang. SAC 2013. [pdf]

Solving quadratic equations with XL on parallel architectures.
Chen-Mou Cheng, Tung Chou, Ruben Niederhagen, Bo-Yin Yang. CHES 2012. [pdf]

Efficient parallel evaluation of multivariate quadratic polynomials on GPUs.
Satoshi Tanaka, Tung Chou, Bo-Yin Yang, Chen-Mou Cheng, Kouichi Sakurai. WISA 2012. [pdf]

Fast exhaustive search for polynomial systems in F₂.
Charles Bouillaguet, Hsieh-Chung Chen, Chen-Mou Cheng, Tung Chou, Ruben Niederhagen, Adi Shamir, Bo-Yin Yang. CHES 2010. [pdf]

Theses

PhD thesis: Accelerating Pre- and Post-Quantum Cryptography, Technische Universiteit Eindhoven, 2016. [pdf]

Master thesis: 解佈於二元體之多項式方程組之快速窮舉法 (Fast Exhaustive Search for Polynomial Systems over F₂), National Taiwan University, Taiwan, 2010. [pdf]

Conference organization

I have contributed to the following events:

ECC 2024, October 30 - November 1, 2024, Taipei, Taiwan [Chair].
CHES 2021, September 12-15, 2021, Beijing, China [PC member].
CHES 2020, September 14-17, 2020, virtual conference [PC member].
CBCrypto 2020, May 9-10, 2020, Zagreb, Croatia [PC member].
PQCrypto 2020, April 15-17, 2020, Paris, France [PC member].
A2C 2019, December 5-7, 2019, Dakar, Senegal [PC member].
CBC 2019, May 18-19, 2019, Darmstadt, Germany [PC member].
LATINCRYPT 2017, Sep 20-22, 2017, La Habana, Cuba [PC member].
CHES 2017, Sep 25-28, 2017, Taipei, Taiwan [PC member].
PKC 2016, March 6-9, 2016, Taipei, Taiwan [PC member].
PQCrypto 2011, Nov 6-Dec 2, 2011, Taipei, Taiwan [Organizer].