Entropy Programs

Entropy allows the creation of decentralized signing authorities. Signing authorities exist as WebAssembly programs that can ingest a signature request, and a valid request is signed via a threshold signature scheme from a set of at-stake validators. These requests might include cryptocurrency-based transaction requests, certificate signing requests, or other mediums for cryptographic authentication.

This repository contains libraries, toolchains, utilities, and specifications for writing, configuring, building, and testing the Wasm-based applications for Entropy. In theory, programs can be written in any language that compiles to WebAssembly, which includes all LLVM-supported languages like Rust, AssemblyScript, Zig, C, etc. Thanks to the WebAssembly Component Model, programs can even be reused languages, with the rich typing provided by the component model interfaces.

Example Programs

Build Requirements

Besides the latest stable Rust toolchain, you will also need to install:

• cargo component v0.2.0, a Cargo extension for building Wasm components.
• wasm-tools, to be used by cargo-component.

These can be installed as follows:

cargo install cargo-component --version 0.2.0 &&
cargo install wasm-tools

Alternatively you can build them using the included Dockerfile:

docker build --build-arg PACKAGE=<example name> --output=example-binary .

This will build the specified example and put compiled .wasm in the director ./example-binary.

A Barebones Program: template-barebones

An example of a barebones program is at examples/barebones/src/lib.rs. This example does a simple check on the length of the message to be signed.

You can compile the program by running:

cargo component build --release -p template-barebones --target wasm32-unknown-unknown

This builds the program as a Wasm component at target/wasm32-unknown-unknown/release/template_barebones.wasm.

Example Custody Program with Config: example-basic-transaction

This example validates that an an EVM transaction request recipient exists on a list of allowlisted addresses. It also uses a configuration, which allows the user to modify the allowlisted addresses without having to recompile the program (i.e. update the allowlist from the browser).

You can compile the program by running:

cargo component build --release -p example-basic-transaction --target wasm32-unknown-unknown

Writing your own programs

You can get started with a template program using cargo-generate.

Install cargo-generate:

cargo install cargo-generate

cargo generate entropyxyz/programs --name my-program

You template program is now in the ./my-program directory and ready to be edited. You can run tests as you would a normal rust project with cargo test.

You can compile your program with cargo component:

cargo component build --release --target wasm32-unknown-unknown

If you want to make your program publicly available and open source, and make it possible for others to verify that the source code corresponds to the on-chain binary, you can build it with the Dockerfile included in the template:

docker build --output=binary-dir .

This will compile your program and put the .wasm binary file in ./binary-dir.

Running Tests

Before running the runtime tests, you need to build the template-barebones, infinite-loop and example-custom-hash components. To do this, execute:

cargo component build --release -p template-barebones -p infinite-loop -p example-custom-hash --target wasm32-unknown-unknown`

This will create the components in target/wasm32-unknown-unknown/release/.

Licensing

For the most part, the code in this repository is licensed under AGPL-3.0.

There are some exceptions however:

• The original code in the examples/risc0-zkvm-verification crate comes from RISC Zero's risc0 project, which is licensed under Apache License 2.0.

Modifications made by Entropy to these crates are licensed under AGPL-3.0.