Delight @ Keio SFC-RG

Keio University Nakamura Joint Lab. Delight Group

Delight group is a research group of the Nakamura Joint Research Group at SFC, Keio University, focusing on decentralized and distributed systems. With the spread of the Internet, issues arising from the reliability of information circulating in cyberspace are becoming apparent rapidly. In collaboration with the Data Architecture Lab at Keio Research Institute at SFC, we are working on solving issues of decentralized and distributed systems and on research activities in various application fields.

We are always welcome to new members.
If you are interested in our research, please check the following page.

Research Topics:

Decentralized and Distributed Systems

  • Digital Identity
  • Verifiable Data Architecture
  • Network Architecture

Digital Identity

Digital identity is a set of information in cyberspace that is associated with entities in the real world. Technologies related to digital identity play a significant role as a bridge between cyberspace and physical space. We are discussing and researching the architecture of digital identity infrastructure and the feasibility of self-sovereign identity from the viewpoint of "trust."

Verifiable Data Architecture

To developing digital civilization, It is essential to ensure the reliability of the information we communicate over the Internet. In particular, it is important to verify the authenticity of data that describes certain information and to efficiently process the described information (machine readability). We are researching system architectures that apply data models based on Verifiable Credentials and Decentralized Identifiers, which W3C is standardizing.

Network Architecture

Knowledge of computers and networks is essential when discussing digital identities and verifiable data architectures, including distributed systems, network security, and communication protocols. At Delight, we build our network systems from physical machines for research purposes, and they also build and operate virtual machines in the network to test and experiment with software they have created. Students can acquire knowledge of both hardware and software.


Ryosuke Abe, project research associate, won the Best Paper Award at the Asian Internet Engineering Conference (AINTEC) 2023.

Dec 22, 2023
We are pleased to announce that Ryosuke Abe, a project research associate in our group, presented a paper at the Asian Internet Engineering Conference (AINTEC) 2023 and won the Best Paper Award. In this study, they measured the parties' attitudes in the order transaction on the blockchain-based escrow service by the visualizing transaction history, and they designed an incentive mechanism to make the parties behave honestly.

Delight will exhibit at SFC Open Research Forum 2023

Nov 24, 2023
Nakamura Joint Laboratory Delight Group will exhibit at SFC Open Research Forum 2023.

Announcement of reforming a new group "Delight": Kumo and Bcali are now togther.

Sep 27, 2023
We are pleased to announce that Kumo and Bcali, which are parts of SFC-RG groups, have been merged into a new group, "Delight", following the developmental dissolution of both of them. The new group "Delight" will continue the activities of Kumo and Bcali, especially focus on research and development related to "distributed systems" and "decentralized systems".


Mitigation of Seller and Buyer's Dilemma with Transaction History and Escrow

In this paper, to estimate the risk of economic loss incurred by both parties in production order transactions, we propose a scheme that enables escrow and confirmation of the results without relying ...
Ryosuke Abe,Seiyo Kurita,Mariko Kobayashi,Shigeya Suzuki
Proceedings of the 18th Asian Internet Engineering Conference 2023 (AINTEC '23), ACM
Dec 2023

A System for Selective Disclosure of Information about a Patient with Intractable Disease

To receive effective treatment during emergency response due to seizures or unforeseen accidents, a patient with intractable diseases must disclose information about their disease to an emergency phys...
Erika Sugita,Ryosuke Abe,Shigeya Suzuki,Keisuke Uehara,Osamu Nakamura
2023 IEEE 47th Annual Computers, Software, and Applications Conference (COMPSAC)
Jul 2023

A new scheme combining zk Rollup on top of Optimistic Rollup to make transactions cheaper without compromising security

Transaction processing capacity limits the utility of Ethereum, one of the most well-known blockchain mainly used as a decentralized application. To enable more diverse applications, it is required to...
Ko Kikuchi
Mar 2023

Textual Summarization system of Human Personalities from Video

This project proposes a system that identifies and analyzes the human personalities from the long video with 2 persons having a conversation. This will be accompanied by a labeling system that correct...
Yubin Kwon
Sep 2022
* Includes papers published in former groups, Kumo and Bcali.



Shigeya Suzuki's portrait

Shigeya Suzuki

Project Professor

Achmad Husni Thamrin's portrait

Achmad Husni Thamrin

Project Associate Professor

Ryosuke Abe's portrait

Ryosuke Abe

Project Research Associate

Graduate Students

wokashi's portrait


Master's Student

moz's portrait


Master's Student

Cryptographic Protocol
Distributed Consensus

Undergraduate Students

kekeho's portrait


Group Leader

Self-Sovereign Identity
Decentralized System
rihib's portrait


Vice Group Leader

sogo's portrait


Undergraduate Student

taru's portrait


Undergraduate Student

Data Security
jamiroq's portrait


Undergraduate Student

Distributed Consensus
tony's portrait


Undergraduate Student

uchiyoshi's portrait


Undergraduate Student

yum's portrait


Undergraduate Student

Digital Identity
Data Security
Data Architecture
yunative's portrait


Undergraduate Student

Distributed System
Large-scale Software
otter's portrait


Undergraduate Student

vito's portrait


Undergraduate Student

guredora's portrait


Undergraduate Student

Web System
loishi's portrait


Undergraduate Student

Digital Identity
ryota-iso's portrait


Undergraduate Student

olatac's portrait


Undergraduate Student

Digital Identity
tatsumi's portrait


Undergraduate Student

Distributed System
the Internet


5322 Endo, Fujisawa, Kanagawa, Japan; Zip: 252-0882
Delta build. North, Keio University SFC
We have regular meetings at ΔN111 every Mon 2nd and Thu 4th-5th period during the spring semester in 2024.
© 2023 Keio University Nakamura Joint Lab. Delight Group