spartan-farmer

A proof-of-concept farmer for the Subspace Network Blockchain

Overview

Notes: The code is un-audited and not production ready, use it at your own risk.

Subspace is a proof-of-storage blockchain that resolves the farmer's dilemma, to learn more read our whitepaper.

This a bare-bones farmer for the simplified Spartan proof-of-space variant of Subspace. A farmer is similar to a miner in a proof-of-work blockchain, but instead of wasting CPU cycles, it wastes disk space. Much of this code has been based on subspace-core-rust.

The farmer basically has two modes: plotting and farming.

Plotting

  1. A genesis piece is created from a short seed.
  2. A new Schnorr key pair is generated, and the farmer ID is derived from the public key.
  3. New encodings are created by applying the time-asymmetric SLOTH permutation as encode(genesis_piece, farmer_id, plot_index)
  4. Each encoding is written directly to disk.
  5. A commitment, or tag, to each encoding is created as hmac(encoding, salt) and stored within a binary search tree (BST).

This process currently takes ~ 36 hours per TB on a quad-core machine.

Solving

Once plotting is complete the farmer may join the network and participate in consensus.

  1. Connect to a client and subscribe to slot_notifications via JSON-RPC.
  2. Given a challenge as hash(epoch_randomness||slot_index) andSOLUTION_RANGE`.
  3. Query the BST for the nearest tag to the challenge.
  4. If it within SOLUTION_RANGE return a SOLUTION else return None

Using Docker

The simplest way to use spartan-farmer is to use container image: bash docker volume create spartan-farmer docker run --rm -it --mount source=spartan-farmer,target=/tmp/spartan subspacelabs/spartan-farmer --help

spartan-farmer is the volume where plot and identity will be stored, it only needs to be created once.

Install (manually)

Instead of Docker you can also install spartan-farmer natively by compiling it using cargo.

Notes: This will currently only work on Mac and Linux, not Windows.

If you have not previously installed the gmp_mpfr_sys crate, follow these instructions.

RocksDB on Linux needs LLVM/Clang: bash sudo apt-get install llvm clang

Then install the framer using Cargo: cargo +nightly install spartan-farmer

NOTE: Above command requires nightly compiler for now, make sure to install it if ou don't have one yet: rustup toolchain install nightly

Usage

Commands here assume you installed native binary, but you can also easily adapt them to using with Docker.

Use --help to find out all available commands and their options: spartan-farmer --help

Create a New Plot

spartan-farmer plot <optional parameters> <piece-count> <seed>

This will create a 1 GB plot: spartan-farmer plot 256000 test

For all supported options check help: spartan-farmer plot --help

By default, plots are written to the OS-specific users local data directory.

``` Linux $XDGDATAHOME or /home/alice/.local/share $HOME/.local/share

macOS $HOME/Library/Application Support /Users/Alice/Library/Application Support

Windows {FOLDERID_LocalAppData} C:\Users\Alice\AppData\Local ```

Start the farmer

RUST_LOG=debug spartan-farmer farm

This will connect to local node and will try to solve on every slot notification.