ROFL Paymaster

End-to-end system for redeeming ROSE on Oasis Sapphire when users deposit tokens on a remote EVM chain. The project combines on-chain contracts, an off-chain relayer, and ROFL infrastructure backed by Hashi proofs.

System Foundations

This system is built on Hashi, a cross-chain message verification protocol, with ROFL integration:

• Hashi Protocol - Cross-chain message verification framework
• ROFL Adapter - Part of the ROFL Header Oracle that runs in a TEE (Trusted Execution Environment) and securely pushes block headers from remote EVM chains to Sapphire
• HashiProver - Contract (contracts/contracts/hashi/prover/HashiProver.sol) that verifies Merkle proofs against the block headers provided by the ROFL adapter

Components

• contracts/ – Hardhat workspace for PaymasterVault, CrossChainPaymaster, supporting libraries, and deployment/configuration tasks.
• paymaster-relayer/ – Python relayer that listens for deposits, builds Hashi proofs, and submits transactions locally or through ROFL.

Operational Flows

Manual relay

Deploy and configure the paymaster contracts, and manage vault deposits from the contracts/ workspace via hardhat tasks. Operators fetch block headers (via the header oracle when available), generate a proof for each deposit, and submit it to the Sapphire paymaster to release ROSE manually.

Automated relayer (local)

Run the relayer stack with Docker Compose from the paymaster-relayer/ project. It watches the source vault, builds proofs automatically, and forwards them to Sapphire while you iterate locally.

Automated relayer (ROFL)

Build the relayer container image and deploy it through ROFL. The ROFL deployment consumes the same proof pipeline but benefits from the TEE-backed header oracle for long-lived operation without managing local infrastructure.

Where to Go Next

• Contract deployment, configuration, and manual operation: see contracts/README.md.
• Relayer setup, ROFL deployment, and local development: see paymaster-relayer/README.md.

For repository-wide conventions and linting utilities, use the top-level Makefile targets.

License

Licensed under Apache 2.0. Portions derived from the Hashi project remain subject to the original LGPL-3.0 terms—review both licenses before redistribution.