Ethers.Authorization (Ethers v0.8.0)

EIP-7702 authorization.

An authorization is a signed permit by which an externally-owned account (the authority) designates contract code to run in its place: once included in a type-4 transaction (Ethers.Transaction.Eip7702), the authority's account code is set to the delegation designator 0xef0100 ++ address, making every call to the EOA execute the delegate contract's code.

The signed payload is not the tuple itself but its EIP-7702 hash:

keccak256(0x05 ++ rlp([chain_id, address, nonce]))

To produce a signature use Ethers.sign_authorization/2, which routes through the configured Ethers.Signer. The signed counterpart is Ethers.Authorization.Signed.

Fields

chain_id - chain where the authorization is valid. 0 makes it valid on every chain — one signature delegates the authority everywhere (the nonce must still match on each chain). Only use 0 deliberately.
address - the delegate contract whose code the authority's account will run. The zero address clears an existing delegation (see clear/1).
nonce - the authority's account nonce at the time the authorization is applied on chain. When the authority itself sends the type-4 transaction (self-sponsoring), the transaction increments the account nonce first, so the authorization nonce must be the current nonce plus one — see the :executor option of Ethers.sign_authorization/2.

A mismatched nonce (or a signature with a high s value) does not fail the transaction; the authorization is silently skipped on chain, so getting these right matters.

Summary

Types

t()

An unsigned EIP-7702 authorization incorporating the following fields

Functions

clear(params)

Creates an authorization that clears the authority's delegation.

clear!(params)

Same as clear/1 but raises on error.

hash(authorization)

Calculates the EIP-7702 signing hash of an authorization.

new(params)

Creates a new authorization struct with the given parameters.

new!(params)

Same as new/1 but raises on error.

Types

t()

@type t() :: %Ethers.Authorization{
  address: Ethers.Types.t_address(),
  chain_id: non_neg_integer(),
  nonce: non_neg_integer()
}

An unsigned EIP-7702 authorization incorporating the following fields:

chain_id - chain ID the authorization is valid on, or 0 for every chain
address - the delegate contract address
nonce - the authority's account nonce at the time the authorization applies

Functions

clear(params)

@spec clear(map() | Keyword.t()) :: {:ok, t()} | {:error, reason :: atom()}

Creates an authorization that clears the authority's delegation.

Same as new/1 with the zero address: applying it resets the authority's account code to empty instead of writing a delegation designator. This is the only way to remove an EIP-7702 delegation. The authority's nonce is still consumed.

Examples

iex> Ethers.Authorization.clear(chain_id: 1, nonce: 8)
{:ok, %Ethers.Authorization{chain_id: 1, address: "0x0000000000000000000000000000000000000000", nonce: 8}}

clear!(params)

@spec clear!(map() | Keyword.t()) :: t() | no_return()

Same as clear/1 but raises on error.

hash(authorization)

@spec hash(t()) :: <<_::256>>

Calculates the EIP-7702 signing hash of an authorization.

Returns the 32-byte digest of keccak256(0x05 ++ rlp([chain_id, address, nonce])).

new(params)

@spec new(map() | Keyword.t()) :: {:ok, t()} | {:error, reason :: atom()}

Creates a new authorization struct with the given parameters.

Accepts a map or a keyword list with the :chain_id, :address and :nonce keys, all required. See the module documentation for the field semantics.

Examples

iex> Ethers.Authorization.new(chain_id: 1, address: "0x90f8bf6a479f320ead074411a4b0e7944ea8c9c1", nonce: 7)
{:ok, %Ethers.Authorization{chain_id: 1, address: "0x90F8bf6A479f320ead074411a4B0e7944Ea8c9C1", nonce: 7}}

new!(params)

@spec new!(map() | Keyword.t()) :: t() | no_return()

Same as new/1 but raises on error.