ethereum.forks.prague.vm.eoa_delegationethereum.forks.osaka.vm.eoa_delegation

Set EOA account code.

SET_CODE_TX_MAGIC

28
SET_CODE_TX_MAGIC = b"\x05"

EOA_DELEGATION_MARKER

29
EOA_DELEGATION_MARKER = b"\xef\x01\x00"

EOA_DELEGATION_MARKER_LENGTH

30
EOA_DELEGATION_MARKER_LENGTH = len(EOA_DELEGATION_MARKER)

EOA_DELEGATED_CODE_LENGTH

31
EOA_DELEGATED_CODE_LENGTH = 23

REFUND_AUTH_PER_EXISTING_ACCOUNT

32
REFUND_AUTH_PER_EXISTING_ACCOUNT = 12500

NULL_ADDRESS

33
NULL_ADDRESS = hex_to_address("0x0000000000000000000000000000000000000000")

is_valid_delegation

Whether the code is a valid delegation designation.

Parameters

code: bytes The code to check.

Returns

valid : bool True if the code is a valid delegation designation, False otherwise.

def is_valid_delegation(​code: bytes​) -> bool:
37
    <snip>
52
    return (
53
        len(code) == EOA_DELEGATED_CODE_LENGTH
54
        and code[:EOA_DELEGATION_MARKER_LENGTH] == EOA_DELEGATION_MARKER
55
    )

get_delegated_code_address

Get the address to which the code delegates.

Parameters

code: bytes The code to get the address from.

Returns

address : Optional[Address] The address of the delegated code.

def get_delegated_code_address(​code: bytes​) -> Optional[Address]:
59
    <snip>
73
    if is_valid_delegation(code):
74
        return Address(code[EOA_DELEGATION_MARKER_LENGTH:])
75
    return None

recover_authority

Recover the authority address from the authorization.

Parameters

authorization The authorization to recover the authority from.

Raises

InvalidSignatureError If the signature is invalid.

Returns

authority : Address The recovered authority address.

def recover_authority(​authorization: Authorization​) -> Address:
79
    <snip>
98
    y_parity, r, s = authorization.y_parity, authorization.r, authorization.s
99
    if y_parity not in (0, 1):
100
        raise InvalidSignatureError("Invalid y_parity in authorization")
101
    if U256(0) >= r or r >= SECP256K1N:
102
        raise InvalidSignatureError("Invalid r value in authorization")
103
    if U256(0) >= s or s > SECP256K1N // U256(2):
104
        raise InvalidSignatureError("Invalid s value in authorization")
105
106
    signing_hash = keccak256(
107
        SET_CODE_TX_MAGIC
108
        + rlp.encode(
109
            (
110
                authorization.chain_id,
111
                authorization.address,
112
                authorization.nonce,
113
            )
114
        )
115
    )
116
117
    public_key = secp256k1_recover(r, s, U256(y_parity), signing_hash)
118
    return Address(keccak256(public_key)[12:32])

access_delegation

Get the delegation address, code, and the cost of access from the address.

Parameters

evm : Evm The execution frame. address : Address The address to get the delegation from.

Returns

delegation : Tuple[bool, Address, Bytes, Uint] The delegation address, code, and access gas cost.

def access_delegation(​evm: Evm, ​​address: Address​) -> Tuple[bool, Address, Bytes, Uint]:
124
    <snip>
140
    tx_state = evm.message.tx_env.state
141
142
    code = get_code(tx_state, get_account(tx_state, address).code_hash)
143
    if not is_valid_delegation(code):
144
        return False, address, code, Uint(0)
145
146
    address = Address(code[EOA_DELEGATION_MARKER_LENGTH:])
147
    if address in evm.accessed_addresses:
148
        access_gas_cost = GasCosts.WARM_ACCESS
149
    else:
150
        evm.accessed_addresses.add(address)
151
        access_gas_cost = GasCosts.COLD_ACCOUNT_ACCESS
152
    code = get_code(tx_state, get_account(tx_state, address).code_hash)
153
154
    return True, address, code, access_gas_cost

validate_authorization

Check if the given Authorization is valid against the current state.

Returns the authority address or None if the validation was unsuccessful.

def validate_authorization(​message: Message, ​​auth: Authorization​) -> None | Address:
160
    <snip>
166
    tx_state = message.tx_env.state
167
168
    if auth.chain_id not in (message.block_env.chain_id, U256(0)):
169
        return None
170
171
    if auth.nonce >= U64.MAX_VALUE:
172
        return None
173
174
    try:
175
        authority = recover_authority(auth)
176
    except InvalidSignatureError:
177
        return None
178
179
    message.accessed_addresses.add(authority)
180
181
    authority_account = get_account(tx_state, authority)
182
    authority_code = get_code(tx_state, authority_account.code_hash)
183
184
    if authority_code and not is_valid_delegation(authority_code):
185
        return None
186
187
    authority_nonce = authority_account.nonce
188
    if authority_nonce != auth.nonce:
189
        return None
190
191
    return authority

set_delegation

Set the delegation code for the authorities in the message.

Parameters

message : Transaction specific items.

Returns

refund_counter: U256 Refund from authority which already exists in state.

def set_delegation(​message: Message​) -> U256:
195
    <snip>
209
    tx_state = message.tx_env.state
210
    refund_counter = U256(0)
211
    for auth in message.tx_env.authorizations:
212
        match validate_authorization(message, auth):
213
            case None:
214
                continue
215
            case authority:
216
                pass
217
218
        if account_exists(tx_state, authority):
219
            refund_counter += U256(
220
                GasCosts.AUTH_PER_EMPTY_ACCOUNT
221
                - REFUND_AUTH_PER_EXISTING_ACCOUNT
222
            )
223
224
        if auth.address == NULL_ADDRESS:
225
            code_to_set = b""
226
        else:
227
            code_to_set = EOA_DELEGATION_MARKER + auth.address
228
        set_code(tx_state, authority, code_to_set)
229
230
        increment_nonce(tx_state, authority)
231
232
    if message.code_address is None:
233
        raise InvalidBlock("Invalid type 4 transaction: no target")
234
235
    message.code = get_code(
236
        tx_state, get_account(tx_state, message.code_address).code_hash
237
    )
238
239
    return refund_counter