Foundry

Signature Replay

Signing messages off-chain and having a contract that requires that signature before executing a function is a useful technique.

For example this technique is used to:

• reduce number of transaction on chain
• gas-less transaction, called meta transaction

Vulnerability

• Same signature can be used multiple times to execute a function.
• This can be harmful if the signer's intention was to approve a transaction once.

Preventative Techniques

• Sign messages with nonce and address of the contract.

Usage

Build

$ forge build

Test

$ forge test

Format

$ forge fmt

Gas Snapshots

$ forge snapshot

Anvil

$ anvil

Deploy

$ forge script script/Counter.s.sol:CounterScript --rpc-url <your_rpc_url> --private-key <your_private_key>

Cast

$ cast <subcommand>

Help

$ forge --help
$ anvil --help
$ cast --help