FedCoin

A Peer-to-Peer Payment System for Federated Learning

Layered Architecture

• Data (Transaction, Block, ChainStructure, etc.)
• Network (Message, P2P, etc.)
• Consensus (Consensus, PoSap, etc.)
• Incentive
• Contract
• Application (Application, FedCoin, etc.)

Usage

Prepare

To build and run FedCoin, you must ensure the following software or package(s) are installed in your experimental computer(s):

• Docker (Mirror: TUNA)
• Python 3.7
• TensorFlow 2.3.0 (Mirror: Google China)

Moreover, Linux distribution like Ubuntu 16.04.7 LTS is recommended as the operating system. Anaconda (Mirror: TUNA) is recommended as the environment manager. Run the conda create -n fedcoin python=3.5 tensorflow-gpu command, and the python -m pip install docker command in new created fedcoin environment could easily get a basic running environment.

Generate weights

Run the following codes in the Python environment to generate weights:

from blockchain.application.fedcoin import FedCoin
FedCoin.run_fl_server()

Set parameters

Parameters are defined in blockchain/util/settings.py, which are showed as follows:

Parameter	Description	Type	Range	Default
K	Number of FL clients	int	[2, inf]	20
R	Number of replicas (miners)	int	[2, inf]	2
D	Difficulty in mining	float	[0.0, inf]	1.5
PRICE	Amount of FedCoins as rewards	float	[0.0, inf]	1000.0
RUNTIME	Time to mine in a round	float	[0.0, inf]	15.0
TRAIN_PRICE	Payments to the FL clients	float	[0.0, 1.0]	0.7
COM_PRICE	Payments to the FL server for processing the model aggregation	float	[0.0, 1.0]	0.1
SAP_PRICE	Payments yo the blockchain network miners for calculating SV	float	[0.0, 1.0]	0.2

Note: The condition "TRAIN_PRICE + COM_PRICE + SAP_PRICE = 1" should be satisfied.

Build and run

The shell code python main.py will build fedcoin and fedcoin_lw images, and run several fedcoin containers that matches the number of replicas defined in settings.

Run docker run fedcoin_lw will start publishing tasks.

The batch file clean.sh will stop and delete containers, as well as delete images that are untagged.

References

• Yuan Liu, Zhengpeng Ai, Shuai Sun, Shuangfeng Zhang, Zelei Liu, Han Yu. FedCoin: A Peer-to-Peer Payment System for Federated Learning. In Book "Federated Learning: Privacy and Incentive" (DOI:10.1007/978-3-030-63076-8_9)
• Yuan Liu, Shuai Sun, Zhengpeng Ai, Shuangfeng Zhang, Zelei Liu, Han Yu. FedCoin: A Peer-to-Peer Payment System for Federated Learning. In arXiv (arXiv:2002.11711)