Minicash

The author is NOT a cryptographer and has not tested the libraries used or the code nor has anyone reviewed the work. This means it's very likely a fatal flaw somewhere. This is meant only as educational and is not production ready.

Minimal implementation of ecash based on David Wagner's variant of Chaumian blinding as described on this cypherpunk mailing list post. Some implementation details follow this description. Uses libsecp256k1, but this doesn't guarantee that either the ffi binding lib or the author didn't make a mistake when calling functions from this lib.

Install the dependencies secp256k1-py, flask and requests.

All can be installed with

pip3 install -r requirements.txt

To test this, you need to run the server first. This is done by running flask run. Example of interaction is in run_example.py and can be tested with python3 run_example.py.

The API contains only three endpoints:

• /keys - used to communicate the public keys for each amount variant.
• /mint - used for minting new coins. It returns a promise for 64 coins.
• /split - consumes proofs of promise and creates new promises based on the split amount.

NOTE: A serious implementation should at least include wallet level locking to avoid race conditioning updates as well as atomic guarantees in the split function.

LICENSE

The code in this repository is under MIT license. Some of the dependencies used use a different license including BSD-3, Apache 2.0 and MPL 2.0. I am no lawyer so I can't advise you if or when you can use this meaning it's up to you to figure out whether you can use this in your project.