Noobcash

This project was developed in the context of undergrad course "Distributed Systems" at NTUA

It is a simple blockchain cryptocurrency, implemented with flask over REST API

Authors
Apostolis Stamatis (@apostolis1)
Dimitrios Mitropoulos (@dimitrismit)

Installation

All the required packages are included in requirements.txt, simply install them with

pip3 install -r requirements.txt

After that, you can start the flask server with the command

python3 rest.py -p PORT_HERE -i IP_HERE

Both the -p and -i parameters are optional

Please note that only the bootstrap node should be running on port 5000 due to a hardcoded check and that bootstrap's server should be the first one to start since all the other servers are using its /register endpoint

Client

A cli interface is implemented for users that offers the following functionalities:

• Make new transactions
• View wallet balances
• View transactions included in last block

There are two different ways the user can use the client:

Interactive

The more user-friendly approach, started with python3 client.py i

A demo can be seen below (the quality is low due to gif encoding)

CLI

The options provided are:

• python3 client.py t -s SENDER_ID -r RECEIVER_ID -a AMOUNT to create new transaction
• python3 client.py view to view the transactions included in the last block
• python3 client.py balance to view each wallet's balance
• python3 client.py f -s SENDER_ID --file TRANSACTIONS_FILE to create transactions from file

Note that the client is communicating directly with the corresponding server when creating a new transaction (either a single one or reading from the file)

This means that if the corresponding server is only reachable from inside a private network, the client should be run from inside the private network as well

Testing

Unittest is used for testing

From the /src diretory run

python3 -m unittest discover -s ../tests/

Network Infrastructure

Below is the infrastructure we used for our benchmarks with 5 nodes (a similiar one was used for the case of 10 nodes)

Future Directions

Some considerations that were not polished due to lack of time:

• Explore optimal data structures for our use cases
• Better testing/fix old testing code
• Implement a UI for the end user as an addition to the CLI