Fuel Bridge Message Predicates

Most messages sent from the base chain to Fuel will use a predicate as the message recipient. These predicates allow anyone to spend the InputMessage but verifies that a specific script is used in the transaction to ensure security and reliability that the message is handled appropriately.

Message to Contract Predicate

The Message to Contract Predicate is for messages that are trying to send a data payload to a designated Fuel contract. This predicate verifies that the script bytecode hash for the transaction matches for the designated Message to Contract Script and that there are no other InputMessages with data in the transaction other than the first input. If these conditions are met, then the predicate evaluates as true.

Message to Contract Script

The message to contract predicate relies on a script that performs only the following operation:

• Call the function process_message on the contract with ID that matches the first 32 bytes in the message data field, while forwarding the exact amount of base asset specified in the InputMessage amount field

Building From Source

Dependencies

dep	version
Forc	0.35.0

Building

Build:

forc build
cargo run

Run tests:

cargo test

Contributing

Code must be formatted.

forc fmt
cargo fmt

License

The primary license for this repo is Apache 2.0, see LICENSE.