A simple implementation of a cryptocurrency, intended for teaching.

The Git history is structured in logical steps, building from a simple "bank" server to a fully trustless currency. At the tagged steps, the code is fully functional and can be used to demonstrate.

Storage is inefficient, intended for reading by humans (and modifying and seeing what happens). There is currently no distributed communication; the intention is to broadcast transactions and blocks to a known fixed set of servers.

BenderCoin requires Python 3.6 and pipenv. It uses the following libraries:

• Flask for the webserver
• Click for command-line client
• requests for communication
• Ed25519 for signatures
• base58 for addresses
• attrs for classes without boilerplate
• termcolor for pretty colors

With existing Python 3.6 installation, you can get all of it like this:

python3.6 -m ensurepip
# use "python3.6 -m ensurepip --user" if you don't have root
python3.6 -m pip install pipenv
# again, add "--user" if you don't have root
cd /path/to/bendercoin
pipenv install

From the checkout directory, run the server:

export FLASK_APP="bendercoin/bank.py"
# add the following if you want live-reload
# export FLASK_DEBUG=1
# but note that clever people will hack your server with it :)
pipenv run python -m flask run

Run commands from the client:

pipenv shell
# show list of commands
python -m bendercoin.client
# run a command
python -m bendercoin.client send fry leela 500 -m "money"

The code is available under MIT license.