EIP712#
Hashing Typed Data#
EIP712 is a protocol for standardizing the signing of typed data. This is useful for contracts where you might need to verify an offchain signature onchain. The digest that is signed consists of two parts: the domain and the message. The message is also sometimes referred to as the struct or the payload.
In order to buid the typed data, you need to use the EIP712Model, which inherits from the Struct model but adds additional capabilities. You are able to build your typed data like this example:
from eth_rpc.types import EIP712Model, hash_eip712_bytes
class Person(EIP712Model):
name: str
wallet: primitives.address
class Mail(EIP712Model):
from_: Person = Field(serialization_alias="from")
to: Person
contents: str
mail = Mail(
from_=Person(name="Cow", wallet="0xCD2a3d9F938E13CD947Ec05AbC7FE734Df8DD826"),
to=Person(name="Bob", wallet="0xbBbBBBBbbBBBbbbBbbBbbbbBBbBbbbbBbBbbBBbB"),
contents="Hello, Bob!",
)
domain = Domain(
name="Ether Mail",
version="1",
chain_id=1,
verifying_contract="0xCcCCccccCCCCcCCCCCCcCcCccCcCCCcCcccccccC",
)
hashed_mail = hash_eip712_bytes(domain, mail)
Signing the Hashed Data#
If you need to sign this hashed data, you can easily do it with the PrivateKeyWallet class: