tutorial

HoneyBadgerMPC Tutorial

This folder (apps/tutorial) contains a few tutorials as a starting point for developing with HoneyBadgerMPC. The tutorials assume you have a working development environment (instructions).

I. hbmpc-tutorial-1.py

The first tutorial gives a tour of the MPC programming environment. To summarize:

• Secret shares are represented by a Share object.
• linear operations on Share objects are just computed locally
• share.open(): causes the servers to communicate with each other to open a share
• ctx.preproc.get_random(): (and related functions) can be used to get fetch random Shares from preprocessing. This is used when multiplying two Share objects
• a Share supports dataflow programming with Futures, like in Viff
• SharreArray(shares).open(): batch methods (TODO)
• an MPC program run is always run in an MPC context, like def my_mpc_program(ctx, ...). When it's running, ctx.myid gives the name of the currently running server
• The simplest way to run the MPC program is with TaskProgramRunner, which runs each server as a lightweight process in a simulated network. This is the simplest operating mode, so it's the way to start when writing an MPC program and testing it
• There are some lines you can uncomment to simulate Byzantine faults and see how HoneyBadgerMPC handles them

Simple MPC programs:

• beaver_multiply the hello world of MPC program
• random_permute_pair as used in the mixing application
• dot product

More examples of this programming model can be found in:

• honeybadgermpc/progs/mixins/share_arithmetic.py
• operations on fixed-point numbers (rather than field elements) honeybadgermpc/progs/fixedpoint.py (TODO)
• honeybadgermpc/progs/mimc.py symmetric key cryptography
• honeybadgermpc/progs/jubjub.py public key cryptography
• apps/asynchromix/butterfly_network.py switching network based on the random pair permutation

To check the development environment works:

• Follow these instructions to set up the docker-compose development environment
• The tutorials assume you have a shell session in the development container, so run:

$ docker-compose run --rm honeybadgermpc bash
root@{containerid}:/usr/src/HoneyBadgerMPC# python apps/tutorial/hbmpc-tutorial-1.py

and look for the output Tutorial 1 ran successfully

II. hbmpc-tutorial-2.py

The second tutorial shows how to run the MPC program in different processes that communicate over sockets. Run it with

scripts/launch-tmuxlocal.sh apps/tutorial/hbmpc-tutorial-2.py conf/mpc/local

This scripts launches 4 processes (in the n=4,t=1 setting) each in its own terminal subwindow. You can crash one other terminals at any time, the rest will still be available.

This script also creates a simulated latency using the tc tool (look for the call to scripts/latency-control.sh. The latency and jitter can be changed by modifying the script.

III. Blockchain integration

Tutorial coming soon... but for now you can run and look at the examples in apps/asynchromix which uses Ethereum (web3py library, and a Solidity smart contract) as an MPC coordinator and broadcast channel.

python apps/asynchromix/asynchromix.py