Overlay Networks:
Group project

Final Presentation

by Yury Belevskiy, Silvan Imhof, Christian Killer, Sebastian Schrepfer

live slides

Overview

1. Architecture

2. Business Case

3. Challenges and Problems

4. Demonstration

goo.gl/39856J

Business Case

1

Business Case

• Two parties are chatting, and they want to have a binding agreement exchanging certain messages
• They don't blindly trust each other and want to be able to prove that one party said something at some point in time
• For messages that deem important, the notary service can be used to save messages into the Ethereum public blockchain
• These messages are immutable by any party
• Any party with the knowledge of the message identifier can look up whether a certain message has truly been sent at which point in time

Contracts-as-a-Service

Architecture

2

Architecture  Full Project

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Product Vision

Architecture  Ethereum

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Web Front-End Technologies

• Spring Boot Application

• Vue.js (& vue-resource)

• WebSockets (SockJS, Stomp)

• REST Interfaces

• Font Awesome

• Local Storage

Notary Technologies

• Ethereum

• Ropsten Testnet

• Smart Contract

• Geth

• Web3J

P2P implementation

• Each user is associated with PeerDHT

• User data is stored in DHT with TTL

• JobScheduler is used to refresh user data and push multiple copies (direct replication)

• Exchange message using FutureDirect

Challenges and Problems

3

Issues experienced

• Ropsten Testnet was under attack multiple times
  • Syncing takes unreasonable amount of time
  • Light mode solves this problem
• Compiling smart contracts locally running Windows is a pain
  • Remix IDE solves this problem
• Documentation and Information about TomP2P, Web3J, Solidity, wrapping etc. exists, but not very extensive
• macOS / Apple failed us
  • Issues with Geth

Conclusion

3

Conclusion 

• SCRUM experience was beneficial in every way
  • Thanks to ti&m and CSG
• Ethereum / Web3j quite steep learning curve
  • A lot of research before first LOC

Demonstration

4

Discussion

5