Joachim Neu

Pronunciation: Joachim [ˈjoːaxɪm] 🔊 Neu [nɔʏ̯] 🔊

Contact: user jneu at organization stanford.edu

Google Scholar / DBLP / Tse Lab @ Stanford / ORCiD: 0000-0002-9777-6168 / Twitter @jneu_net

Short bio: Joachim is a PhD candidate at Stanford advised by David Tse. His current research focus is the science and engineering of Internet-scale consensus (or, if you prefer more hype terms: the technical foundations of blockchains). Recent research projects include provable consensus security for next-generation Ethereum, and provable security and performance of proof-of-stake consensus under rate constraints (communication, processing, ...) and network-level attacks. While a Masters student at Technical University of Munich and a visiting student researcher at MIT, EPFL, and KAUST, he worked in information and coding theory. He has been supported by Protocol Labs PhD Fellowship, Ethereum Foundation, Stanford Graduate Fellowship, and German Academic Scholarship Foundation.

Research

Decentralized systems and algorithms

Preprints

• Security of Blockchains at Capacity
  Lucianna Kiffer^*, Joachim Neu^*, Srivatsan Sridhar^*, Aviv Zohar^*, David Tse
  March 2023
  [ePrint:2023/381] [arXiv:2303.09113]
• No More Attacks on Proof-of-Stake Ethereum?
  Francesco D'Amato^*, Joachim Neu^*, Ertem Nusret Tas^*, David Tse^*
  September 2022
  [ePrint:2022/1171] [arXiv:2209.03255] [Paradigm blog post]
• Proofs of Proof-of-Stake with Sublinear Complexity
  Shresth Agrawal^*, Joachim Neu^*, Ertem Nusret Tas^*, Dionysis Zindros^*
  September 2022
  [ePrint:2022/1642] [arXiv:2209.08673] [Source code: Experiments] [Source code: Kevlar optimistic light client] [Source code: Patronum trust anchor shim]

Peer-reviewed

• Two More Attacks On Proof-of-Stake GHOST/Ethereum
  Joachim Neu^*, Ertem Nusret Tas^*, David Tse
  2022 ACM Workshop on Developments in Consensus (ConsensusDay'22), November 2022
  [doi:10.1145/3560829.3563560] [ePrint:2022/289] [arXiv:2203.01315] [Source code: Avalanche attack] [ETHresear.ch: Avalanche attack] [ETHresear.ch: Balancing attack for LMD]
• Longest Chain Consensus Under Bandwidth Constraint
  Joachim Neu^*, Srivatsan Sridhar^*, Lei Yang^*, David Tse, Mohammad Alizadeh
  4th ACM Conference on Advances in Financial Technologies (AFT'22), September 2022
  [ePrint:2021/1545] [arXiv:2111.12332] [Talk video (Protocol Labs research seminar)] [Source code: Experiments]
  Also non-archival: 5th Science of Blockchain Conference (SBC'22), August 2022
  [Talk video, presented by Srivatsan Sridhar]
  Also non-archival: 2022 ACM Workshop on Developments in Consensus (ConsensusDay'22), November 2022
• Information Dispersal with Provable Retrievability for Rollups
  Kamilla Nazirkhanova^*, Joachim Neu^*, David Tse
  4th ACM Conference on Advances in Financial Technologies (AFT'22), September 2022
  [ePrint:2021/1544] [arXiv:2111.12323] [Source code: Semi-AVID-PR experiments]
• Three Attacks on Proof-of-Stake Ethereum
  Caspar Schwarz-Schilling, Joachim Neu, Barnabé Monnot, Aditya Asgaonkar, Ertem Nusret Tas, David Tse
  26th International Conference on Financial Cryptography and Data Security (FC'22), May 2022
  [doi:10.1007/978-3-031-18283-9_28] [SpringerLink:10.1007/978-3-031-18283-9_28] [ePrint:2021/1413] [arXiv:2110.10086] [Source code: Refined Gasper attack] [Talk video, presented by Caspar Schwarz-Schilling] [Talk video (FC'22 recording, presented by Caspar Schwarz-Schilling)]
• The Availability-Accountability Dilemma and its Resolution via Accountability Gadgets
  Joachim Neu^*, Ertem Nusret Tas^*, David Tse^*
  26th International Conference on Financial Cryptography and Data Security (FC'22), May 2022
  [doi:10.1007/978-3-031-18283-9_27] [SpringerLink:10.1007/978-3-031-18283-9_27] [ePrint:2021/628] [arXiv:2105.06075] [Source code: Accountability gadget prototype] [ETHresear.ch: Refined Gasper attack] [Talk video (FC'22 recording, presented by Ertem Nusret Tas)]
  Also non-archival: Protocol Labs Research ConsensusDays '21, October 2021
  [Talk video]
• Ebb-and-Flow Protocols: A Resolution of the Availability-Finality Dilemma
  Joachim Neu^*, Ertem Nusret Tas^*, David Tse^*
  42nd IEEE Symposium on Security and Privacy (S&P'21), May 2021
  [doi:10.1109/SP40001.2021.00045] [IEEE Computer Society Digital Library] [ePrint:2020/1091] [arXiv:2009.04987] [Source code: Ebb-and-Flow] [Source code: Gasper attack] [ETHresear.ch: Gasper attack] [Video: IEEE S&P'21 60s preview] [Video: IEEE S&P'21 presentation] [Decentralized Thoughts blog post] [Talk at LA Blockchain Summit, presented by David Tse] [Talk at IBM Research Workshop on the Informational Lens, presented by David Tse] [zkCapital This Week in Blockchain Research Issue #74]
  Also non-archival: 3rd Workshop on Theory and Practice of Blockchains, June 2021
  [Talk video]
• Boomerang: Redundancy Improves Latency and Throughput in Payment-Channel Networks
  Vivek Bagaria^*, Joachim Neu^*, David Tse
  24th International Conference on Financial Cryptography and Data Security (FC'20), February 2020
  [doi:10.1007/978-3-030-51280-4_17] [SpringerLink:10.1007/978-3-030-51280-4_17] [arXiv:1910.01834] [Source code]
  Also non-archival: 4th Stanford Blockchain Conference (SBC'20), February 2020
  [Talk video] [Bitcoin Optech Newsletter #86]

Technical reports

• Data Availability Sampling: From Basics to Open Problems
  Joachim Neu
  August 2022
  [Paradigm blog post]
• Cosmos without Tendermint: Exploring Narwhal and Bullshark
  Joachim Neu, Georgios Konstantopoulos, Andrew Kirillov
  July 2022
  [Paradigm blog post]
• Snap-and-Chat Protocols: System Aspects
  Joachim Neu^*, Ertem Nusret Tas^*, David Tse
  October 2020
  [arXiv:2010.10447]

Select survey talks

• Ethereum After The Merge: Is It Still Secure?
  Joachim Neu
  [Seminar talk at EPFL IC Colloquium]
• The Why and How of PoS Ethereum's Consensus Problem
  Joachim Neu
  [Survey talk at Devconnect/Ethconomics 2022]

Polar codes and quantization

Peer-reviewed

• Successive Cancellation Inactivation Decoding for Modified Reed-Muller and eBCH Codes
  Mustafa Cemil Coşkun, Joachim Neu, Henry D. Pfister
  IEEE International Symposium on Information Theory (ISIT), June 2020
  [doi:10.1109/ISIT44484.2020.9174226] [IEEExplore:9174226] [arXiv:2004.05969]
• Ternary Quantized Polar Code Decoders: Analysis and Design
  Joachim Neu, Mustafa Cemil Coşkun, Gianluigi Liva
  53rd Asilomar Conference on Signals, Systems, and Computers, November 2019
  [doi:10.1109/IEEECONF44664.2019.9048843] [IEEExplore:9048843] [arXiv:1910.01176] [Source code]
  Also non-archival: Poster at 2019 North American School of Information Theory (NASIT), July 2019
  [Poster]

Master's thesis

• Quantized Polar Code Decoders: Analysis and Design
  Joachim Neu
  Master's thesis at Technical University of Munich, September 2018
  [arXiv:1902.10395]
  Also non-archival: Talk at 2019 Oberpfaffenhofen Workshop on High Throughput Coding (OWHTC), February 2019
  [Slides]
• Polar.jl: Julia implementation of polar coding
  Joachim Neu
  https://jneu.net/Polar.jl, January 2019
  [Source code]

Multi-user information theory

Peer-reviewed

• Degrees-of-Freedom of the MIMO Three-Way Channel with Node-Intermittency
  Joachim Neu, Anas Chaaban, Aydin Sezgin, Mohamed-Slim Alouini
  IEEE Transactions on Information Theory, October 2019
  Volume: 65, Issue: 10, Pages: 6781-6800
  [doi:10.1109/TIT.2019.2919548] [IEEExplore:8723619] [arXiv:1708.08161]
  Also non-archival: Poster at 2018 IEEE European School of Information Theory (ESIT), May 2018
  [Poster]

Coding for DNA storage

Peer-reviewed

• Overcoming high nanopore basecaller error rates for DNA storage via basecaller-decoder integration and convolutional codes
  Shubham Chandak, Joachim Neu, Kedar Tatwawadi, Jay Mardia, Billy Lau, Matthew Kubit, Reyna Hulett, Peter Griffin, Mary Wootters, Tsachy Weissman, Hanlee Ji
  45th IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP), May 2020
  [doi:10.1109/ICASSP40776.2020.9053441] [IEEExplore:9053441] [bioRxiv:10.1101/2019.12.20.871939] [Supplementary material] [Talk video, presented by Shubham Chandak]
• Improved read/write cost tradeoff in DNA-based data storage using LDPC codes
  Shubham Chandak, Kedar Tatwawadi, Billy Lau, Jay Mardia, Matthew Kubit, Joachim Neu, Peter Griffin, Mary Wootters, Tsachy Weissman, Hanlee Ji
  57th Annual Allerton Conference on Communication, Control, and Computing, September 2019
  [doi:10.1109/ALLERTON.2019.8919890] [IEEExplore:8919890] [bioRxiv:10.1101/770032]

Supplemental

• Large blocklength LDPC codes for Illumina sequencing-based DNA storage
  Shubham Chandak, Kedar Tatwawadi, Billy Lau, Matthew Kubit, Jay Mardia, Joachim Neu, Hanlee Ji, Tsachy Weissman, Peter Griffin, Mary Wootters
  ISMB/ECCB, July 2019
  (Poster) [Talk video, presented by Shubham Chandak]

Coded distributed storage and content delivery

Peer-reviewed

• Babel Storage: Uncoordinated Content Delivery from Multiple Coded Storage Systems
  Joachim Neu, Muriel Médard
  IEEE Global Communications Conference (GLOBECOM), December 2019
  [doi:10.1109/GLOBECOM38437.2019.9013383] [IEEExplore:9013383] [arXiv:1908.09271]

^* Listed alphabetically.