What is hashsigs-solidity?

This repository contains Solidity smart contracts that implement a type of digital signature scheme called WOTS+, short for Winternitz One-Time Signature Plus. Solidity is the programming language used to write code that runs on the Ethereum blockchain, so these contracts are intended to be deployed on a blockchain environment. WOTS+ is a hash-based signature scheme, meaning its security comes from hash functions rather than from the mathematical problems (like factoring large numbers) that underpin most current encryption. Hash-based signatures are considered post-quantum, which means they are believed to remain secure even if large-scale quantum computers become available, since quantum computers are expected to break several of the classical approaches but not hash-based ones. The one-time aspect means each signing key should only be used to sign a single message, reusing it weakens the security guarantees. The project is described as providing a way to verify post-quantum signatures on-chain, which would allow smart contracts to authenticate data using quantum-resistant proofs rather than the standard Ethereum signature scheme. The README is sparse and covers only the development setup. The project uses two Ethereum development tools: Hardhat and Foundry. To get started, you install Foundry and the Node.js dependencies, then run tests with the forge command. A build command compiles the contracts. This is an early or research-grade project from quip.network, available under the GNU Affero General Public License version 3. Beyond the setup instructions, the README does not document the contract interfaces or intended use cases in detail.