We are pleased to invite you to the Fifth International Workshop on Blockchain: Blockchain Kaigi 2025 (BCK25), which will be held from December 4-6, 2025, at the Indian Institute of Technology (IIT) Bombay, India.

Building on the success of previous workshops in Kyoto (BCK21), Tohoku (BCK22), Kobe
(BCK23), and Zurich (BCK24), BCK25 will continue its tradition of bringing together
researchers and practitioners to share the latest findings and innovative solutions in
blockchain technology. We welcome submissions of both theoretical and applied research.

We invite you to submit a 2-page extended abstract describing original, previously
unpublished work. Extended versions of accepted papers will be invited for publication in JPS conference proceedings and a special issue of the Ledger Journal. Please note that for a paper to be included, at least one author must attend the in-person event.

★Key Information★
- Conference Dates: December 4-6, 2025
- Location: IIT Bombay, India
- Submission Deadline: September 15, 2025
- Submission Guidelines: 2-page extended abstract in PDF format.
- Submission Portal: https://easychair.org/conferences?conf=bck25
- Conference Website: https://bck-2025.isrdc.in

★Indicative Topics of Interest★
● Consensus, Fault-tolerance, Scalability
● Cryptography & Mathematics
● Applications in Cybersecurity
● Digital Asset Market, AUM
● Central Bank Digital Currency (CBDC)
● Innovation Policy, SDGs
● Modelling of on-chain activity
● Digital Identity & Privacy
● Token Ecosystem, Finternet
● IoU networks, Settlements
● Lightning networks, Interoperability
● Smart Contract Verification, DAOs
● Smart-Grid, Smart-City
● FinTech, AgTech, HealthTech
● Legal and Regulatory Issues
● Network Science, Hypergraphs
● Innovative Use Cases for public good
● Ledger analytics for privacy and AML
● ML Applications to Blockchain
● Blockchain for AI/ML ecosystem
● Simulation tools
● Visualisation of transaction trails

We look forward to your submissions and to welcoming you to IIT Bombay.

Sincerely,
The BCK25 Organizing Committee