Bitcoin Scalability Workshops

Scaling Bitcoin 2018 "Kaizen" • October 6th-7th Tokyo


Scaling Bitcoin ‘Kaizen’, focuses on the systematic identification of portions of the Bitcoin protocol that best lend themselves to continuous, non-’consensus layer’ improvement.

‘Kaizen’ focuses on the refinement of Bitcoin’s existing impressive security, integrity and performance properties by identifying opportunities to drive further algorithmic efficiency and rigorous testing.

Particular attention will be paid to the precision engineering of all aspects of Bitcoin’s quality assurance processes, such as unit, integration and system-level testing, testnet data gathering and analysis, streamlining toolchain support and the verification and validation of existing integrity testing and distribution approaches.







Workshop Sponsorship

If you are interested in sponsoring the Scaling Bitcoin Workshop, please contact:

Important Dates:

  • 2018-10-01 23:59 UTC - Submission of logos for print (must be submitted in AI or SVG vector file formats)

Travel Subsidy

There exists a number of independent or academic researchers that could be helpful to the process but are unlikely to attend due to cost. The Sponsors of this event have agreed to review applications for travel assistance, and to jointly subsidize the expense of up to $1,500 USD per person for airfare and hotel to the workshop of an estimated 15 persons. The intent is for independence and a diversity of views to be represented in a professional manner, some of which may disagree with the views of the sponsors. Those who work at a company engaged in a related business are expected to cover their own travel expenses. Exceptions could be made on a case-by-case basis at the discretion of the sponsors.

Important Dates:

  • 2018-08-15 23:59 UTC - Last day for travel subsidy application
  • 2018-09-01 23:59 UTC - Deadline for applicant acceptance notification
  • 2018-11-01 23:59 UTC - Deadline for submission of travel receipts

Travel Subsidy Application Questions

If you are interested in applying for travel subsidy, please fill out the following form:

Call for Proposals

The current Scaling Bitcoin Workshop will take place Fall 2018 in Keio University 2 Chome-15-45 Mita, Minato-ku Tōkyō-to 108-8345, Japan. We are accepting technical proposals for improving Bitcoin performance including designs, experimental results, and comparisons against other proposals. The goals are twofold: 1) to present potential solutions to scalability challenges while identifying key areas for further research and 2) to provide a venue where researchers, developers, and miners can communicate about Bitcoin development.

We are accepting two types of proposals: one in which accepted authors will have an opportunity to give a 20-30 minute presentation at the event, and another where accepted authors can run an hour-long interactive workshop.

This year we would like to place a stronger focus on the following topics:

  • Simulation, modeling and testing
  • Methods and tools for simulation and testing of blockchain behavior
  • Game theory and Mechanism Design
  • Fungibility
  • Enhancement of Scripting
  • New Validation Methods
We also welcome compilation/review of material on above topics made available to public since the last Scaling Bitcoin event.

Other topics of interest include:

  • Improving Bitcoin throughput
  • Layer 2 ideas (i.e. payment channels, etc.)
  • Security and privacy
  • Incentives and fee structures
  • Network resilience
  • Anti-spam measures
  • Block size proposals
  • Empirical mining data

All as related to the scalability of Bitcoin.

Apart from general presentations and workshop, we plan to accept a limited number of short engineering presentations to cover state-of-the-art engineering progress after the submission deadline. Details of the short presentation submission will be announced later.

While proposals that may apply to digital currencies in general are welcome, this event deals with the scalability of Bitcoin, and submissions which focus primarily on other digital currency systems are out of scope for this event.

Important Dates

  • 2018-07-10 23:00 UTC - Last day for submission
  • 2018-08-15 23:59 UTC - Last day for notification of acceptance and feedback

Reviewing Process

For the regular presentation proposals, review is conducted by double blind reviewing process. Submissions must be anonymous, with no author name, affiliations, acknowledgement or obvious reference.


Proposals may be submitted as a BIP, as a 1-2 page extended abstract, or a paper describing ideas, designs, and expected experimental results. Indicate in the proposal whether you are interested in speaking, running an interactive workshop, or both. If you are interested in running an interactive workshop, please include an agenda.

All submissions are processed on EasyChair. Please submit your proposal through the following URL:

Proposals should be submitted by 2018-07-10 23:00 UTC.

PLEASE NOTE: Due to multiple requests, after the original date of 2018-07-02, the Program Committee has re-opened submissions on 2018-07-07 16:00 UTC with a firm deadline on 2018-07-10 16:00 UTC.


  • All talks will be live-streamed and published online, including slide decks.
  • Scaling Bitcoin Workshop does not have proceedings.
  • There are no submission restrictions - authors of presented submissions can submit to any other conference.

Call for Proposals to Work-in-progress (WIP) and informative sessions

Scaling Bitcoin Kaizen will include a session for sharing technological progress updates and information to help further thinking and discussions on scalability.

We encourage anyone attending Scaling Bitcoin Kaizen 2018 in Tokyo who is interested in presenting their progress/idea/information to submit a proposal with name, title, affiliation and abstract up to 1 page. The submission deadline is 2018-10-04 23:59 UTC. The time allotment for each presentation will be decided based on the total number of submissions and their contents.

As with general presentations, any advertisement, information regarding specific businesses, or ICOs will not be acceptable. The WIP session will be strictly focused on technical discussion.

Please email your submissions to


How do the Workshops work?

  • Events are live-streamed with remote participation facilitated via IRC for parallel online discussion and passing questions to the event.
  • These workshops aim to facilitate the existing Bitcoin Improvement Proposals process. Most work will be done outside of the workshops in the intervening months. The workshops serve to be additive to the design and review process by raising awareness of diverse points of view, studies, simulations and proposals.
  • Travel, venue details, accommodation recommendation are available below.
  • Please see the FAQ section below, it should answer most other questions.



October 5th
Opening party at Shinagawa Oimachi

October 6th
(30 min)


(10 min)
Introduction to Event
(25 min)
Invited Talk: Deploying Blockchain At Scale. Lessons from the Internet Deployment in Japan.
Professor Jun Murai (Keio University)

Current State of Bitcoin

(30 min)
An Analysis of Dust in UTXO based Cryptocurrencies
Cristina Pérez-Solà, Sergi Delgado Segura, Guillermo Navarro-Arribas and Jordi Herrera (Universitat Autònoma de Barcelona)
(30 min)
How Much Privacy is Enough? Threats, Scaling, and Trade-offs in Blockchain Privacy Protocols
Ian Miers (Cornell Tech)
(15 min)

On-Chain Scaling

(30 min)
Playing With Fire: Adjusting Bitcoin's Block Subsidy
Anthony Towns (Xapo)
(30 min)
Self-Reproducing Coins as Universal Turing Machine
Dmitry Meshkov, Alexander Chepurnoy and Vasily Kharin (Ergo Platform)
(30 min)
Forward Blocks: On-chain/Settlement Capacity Increases Without the Hard-fork
Mark Friedenbach
(90 min)

Scaling Security

(30 min)
Compact Multi-Signatures for Smaller Blockchains
Dan Boneh (Stanford University), Manu Drijvers and Gregory Neven (DFINITY)
(30 min)
Improving SPV Client Validation and Security with Fraud Proofs
Mustafa Al-Bassam (University College London)
(30 min)
A Scalable Drop-in Replacement for Merkle Trees
Benedikt Bünz, Benjamin Fisch and Dan Boneh (Stanford University)
(15 min)

Scriptless Scripts and Multi-party Channels

(30 min)
Multi-party Channels in the UTXO Model: Challenges and Opportunities
Olaoluwa Osuntokun (Lightning Labs)
(30 min)
Multi-Hop Locks for Secure, Privacy-Preserving and Interoperable Payment-Channel Networks
Giulio Malavolta (Friedrich-Alexander-University Erlangen-Nuernberg), Pedro Moreno-Sanchez (Purdue University), Clara Schneidewind (Vienna University of Technology), Aniket Kate (Purdue University) and Matteo Maffei (Vienna University of Technology)
(30 min)
Instantiating [Scriptless] 2P-ECDSA: Fungible 2-of-2 MultiSigs for Today's Bitcoin
Conner Fromknecht (Lightning Labs)
(15 min)
(45 min)
Work-in-Progress Session
Main Reception at Tokyo Design Center

October 7th


(5 min)


(30 min)
OmniLedger: A Secure, Scale-Out, Decentralized Ledger via Sharding
Eleftherios Kokoris-Kogias, Philipp Jovanovic, Linus Gasser, Nicolas Gailly, Ewa Syta and Bryan Ford (Ecole Polytechnique Fédérale de Lausanne)
(30 min)
The GHOSTDAG Protocol
Yonatan Sompolinsky and Aviv Zohar (The Hebrew University of Jerusalem)
(15 min)

Lightning Network

(30 min)
Rebalancing in the Lightning Network: Analysis and Implications
Sebastián Reca (Muun)
(30 min)
Reproductible Lightning Benchmark
Nicolas Dorier (DG Lab)
(30 min)
Incentivizing Payment Channel Watchtowers
Georgia Avarikioti, Felix Laufenberg, Jakub Sliwinski, Yuyi Wang and Roger Wattenhofer (ETH Zurich)
(60 min)


(30 min)
The State of Atomic Swaps
Thomas Eizinger, Lloyd Fournier and Phillip Hoenisch (CoBlox)
(30 min)
Statechains: Off-chain Transfer of UTXOs
Ruben Somsen
(30 min)
Niji: Bitcoin Bridge Utilizing Payment Channels
Hiroki Watanabe, Shigenori Ohashi, Shigeru Fujimura, Atsushi Nakadaira, Kota Hidaka and Jay Kishigami (NTT Service Evolution Labs., NTT Corp.)
(30 min)
Interoperability with Cryptocurrency-backed Tokens
Alexei Zamyatin, Dominik Harz, Joshua Lind, Panayiotis Panayiotou, Arthur Gervais and William J. Knottenbelt (Imperial College London)
(20 min)

Discussion groups

(120 min)
Scriptless scripts, adaptor signatures and their applications (Room #456)
LEADERS: Andrew Poelstra (Blockstream)
The evolution of bitcoin scripting (Room #453)
LEADERS: Olaoluwa Osuntokun (Lightning Labs)
Forward Blocks (Room #455)
LEADERS: Mark Friedenbach
CVE, Vulnerability handling (Room #451)
LEADERS: Braydon Fuller (
Miner bribery and incentives (Room #452)
LEADERS: Joseph Bonneau (New York University)
UTXO/state commitments (Room #457)
LEADERS: Benedikt Bünz (Stanford University)
(45 min)
Wrap up from discussion groups, next steps and close

Remote Participation

Live broadcast will begin Saturday October 5th at:
9:00 JST / 20:00 EST / 12:00 UTC / 17:00 PST
Official live stream feeds will be available through YouTube:
Video Production & Streaming by



Keio University

Keio University - South Building

Main Hall

Main Hall

Main Hall

Keio University

Keio University
2 Chome-15-45 Mita, Minato-ku
Tōkyō-to 108-8345, Japan


We are sorry, but the event has been sold out.
You will still be able to participate via the live stream, IRC, and Twitter.
Due to space limitations, we will not be able to admit anyone at the door.


  • I need some sort of document for a travel visa

    (Info: You are responsible for identifying your own personal visa requirements to enter Japan. If you have any questions please contact

  • I can’t go but I want to participate!

    The event will be livestreamed, and you will be able to participate via IRC. Although it is naturally easier to participate in person, everyone at the event will have a desk in front of them and will be encouraged to join in online discussions with global participants who are viewing the live stream. It is also important to understand that no decisions are to be made at the workshop. (read more below)

  • How do I give a presentation?

    You can submit your proposal to (see CFP above). If you’ve worked on research, we recommend that you post the results, including papers, simulation results, and source code, to the bitcoin-dev discussion list. Depending on the quantity of accepted presentations, the workshop will allot a fair amount of time to each presenter. If people have substantially overlapping plans, they may be suggested to merge. Publishing a paper is NOT required—if you have a good presentation plan, you can propose a detailed summary.

  • Are any decisions made at the workshop?

    Absolutely no decisions are made at workshops, as this would run the risk of being rushed and unfair to the global community unable to attend in person. The workshop is about raising awareness of issues and proposals, finding common ground, and encouraging public discussion within the existing mechanism of technical progress through the Bitcoin Improvement Proposal process.

  • Will there be a debate?

    There will probably be no debate, and the workshop organizers and participants will be operating with the goal of making the event low-stress and non-confrontational. The intent of the workshops are to showcase diverse points of view and promote open-mindedness in order to improve our collective understanding of how to improve Bitcoin’s scalability. In-person debates could too easily do a disservice to the future of Bitcoin in being about solidifying simplified positions for the purpose of winning political points. It would be unreasonable to entrust the safety and security of the future of Bitcoin to smooth talking at a one-time event rather than deliberate technical study with time for the global community to weigh in.

  • Can we discuss governance of the Bitcoin projects at this workshop?

    Scaling Bitcoin Workshops are focused on raising technical awareness of scalability issues, simulations and proposals to improve scalability. Conference participants want this event to be entirely focused on the science and engineering, which is how Open Source Software development has proven to deliver excellence.

  • Future Workshops? Workshop BIP?

    We aim to host a Scaling Bitcoin Workshop once per year. If you would like to host next year's event please e-mail to

  • Are there Vegetarian, Gluten-Free Options for the Food?

    Yes. Please email if we can be of any assistance.

  • Is there Wheel Chair Access to these social events?

    Yes, all venues have been audited and are wheel-chair friendly. Please email if we can be of any assistance.

Online Resources

Traveling to Japan

  • Mobile Internet Access

    If you arrive to Haneda Airport, right as you exit customs into the arrival hall, at your 3-4 o'clock (to the right of the exit) you will find a number of mobile internet providers. You can obtain a local sim that will give you few GB of internet, or you can obtain an LTE/WiFi hotspot that will give you unlimited internet access with up to 150 Mbits downlink at a cost of ~$15/day. If you plan on working during your trip, we highly recommend LTE/WiFi hotspot.

    Internet is especially crucial for navigation. Google maps is extremely helpful when trying to get from point A to point B, but without internet access and thus without Google Maps you may end up being stranded asking for directions.

  • Access to Banking / ATM

    If you need access to an ATM, frequently the best option is to use 7-11 stores. 7-11 stores can be found every few blocks and each 7-11 store has an ATM inside.

  • Payment (Suica cards)

    In Japan, the common form of micro-payments are RFID/NFC cards that can be charged at charging terminals and used in stores.

    As you exit customs, at around 11 o'clock, there is a JR service counter. You can obtain a Suica card there and have them charge it. You can immediately use the Suica card to pay for the subway entrance.

  • Trains & Japan Rail (JR) Lines

    One of the best ways to travel Japan is by Shinkansen trains (known as a Bullet/Arrow train). Tickets to this train are expensive if obtained on the spot. However, foreigners can obtain weekly passes, that allow use of Shinkansen trains and provide for free entry to JR subway lines.

    JR weekly passes can not be purchased in Japan! They can only be obtained from your local travel agency that handles Japanese destinations. The travel agency will provide you with voucher that can then be obtained at the JR service counter in the Haneda airport. You can also get JR passes online, for example here -

    Please note that JR passes do not give you access to all high-speed trains. Specifically you can not take NOZOMI and MIZUHO trains on the Tokaido, Sanyo and Kyushu Shinkansen lines. JR pass holders can use only HIKARI, SAKURA, KODAMA or TSUBAME lines.

    Shinkansen high-speed trains connect directly to subway, are very comfortable and allow you to travel to many locations in Japan within 2-3 hours. You typically do not need reservations as each train contains few non-reserved cars that are typically only half-full.


Scaling Bitcoin Planning Committee

  • Anton Yemelyanov, Base58 Association NPO. (Planning Committee Chair)
  • Nelly Milanova, Base58 Association NPO.
  • Jeremy Rubin, Bitcoin Core Contributor
  • Neha Narula, MIT DCI
  • Ethan Heilman, Boston University
  • Ferdinando M. Ametrano, Bitcoin and Blockchain Technology professor at Politecnico di Milano
  • Byron Gibson, Engineering Consultant and Startup Advisor

Workshop Host Committee

  • Taro Watanabe, Digital Garage (Chairman)
  • Shigeya Suzuki, Keio University
  • Kanta Matsuura, The University of Tokyo
  • Shin'ichiro Matsuo, Georgetown University, BSafe Network
  • Anditto Heristyo, DG Lab

Program Committee

  • Shin'ichiro Matsuo, Georgetown University, BSafe Network (Program Committee Co-Chair)
  • Elaine Ou, Global Financial Access (Program Committee Co-Chair)

Engineering Perspective

  • Bryan Bishop, LedgerX, Bitcoin Core Contributor
  • Riccardo Casatta, Eternity Wall
  • Fabrice Drouin, Acinq
  • Jameson Lopp, BitGo
  • John Newbery, Chaincode
  • Olaoluwa Osuntokun, Lightning Labs
  • Rusty Russel, Blockstream
  • Jonas Schnelli, Bitcoin Core Contributor
  • David Vorick, Nebulous Labs
  • Eric Voskuil, LibBitcoin

Academic Perspective

  • Joseph Bonneau, New York University
  • Benedikt Bunz, Stanford University
  • Ittay Eyal, Technion Israel Institute of Technology
  • Ethan Heilman, Boston University
  • Brian Levine, University of Massachusetts at Amherst
  • Kanta Matsuura, The University of Tokyo
  • Ian Miers, Johns Hopkins University
  • Patrick McCorry, King's College London
  • Shigeya Suzuki, Keio University
  • Aviv Zohar, The Hebrew University of Jerusalem

Subsidy Committee

  • Neha Narula, MIT DCI
  • Nelly Milanova, Base58 Association NPO.
  • Taro Watanabe, Digital Garage
  • Océane Boulais