Update EIP-7702: remove chain_id in authorization tuple

EIPS/eip-7702.md

@@ -41,18 +41,15 @@ We introduce a new [EIP-2718](./eip-2718.md) transaction, "set code transaction"
 ```
 rlp([chain_id, nonce, max_priority_fee_per_gas, max_fee_per_gas, gas_limit, destination, value, data, access_list, authorization_list, signature_y_parity, signature_r, signature_s])
 
-authorization_list = [[chain_id, address, nonce, y_parity, r, s], ...]
+authorization_list = [[unchained, address, nonce, y_parity, r, s], ...]
 ```
 
-The fields `chain_id`, `nonce`, `max_priority_fee_per_gas`, `max_fee_per_gas`, `gas_limit`, `destination`, `value`, `data`, and `access_list` of the outer transaction follow the same semantics as [EIP-4844](./eip-4844.md). *Note, this means a null destination is not valid.*
+The transaction fields `chain_id`, `nonce`, `max_priority_fee_per_gas`, `max_fee_per_gas`, `gas_limit`, `destination`, `value`, `data`, and `access_list` follow the same semantics as [EIP-4844](./eip-4844.md). *Note, this means a null destination is not valid.*
 
-The `authorization_list` is a list of tuples that store the address to code which the signer desires to execute in the context of their EOA. The transaction is considered invalid if the length of `authorization_list` is zero.
-
-The transaction is also considered invalid when any field in an authorization
-tuple cannot fit within the following bounds:
+`authorization_list` is a list of tuples that store the address to code which the signer desires to execute in the context of their EOA. The transaction is considered invalid if the length of `authorization_list` is zero. It is also considered invalid when any field in an authorization tuple exceeds the following bounds:
 
 ```python
-assert auth.chain_id < 2**64
+assert auth.unchained == 0 || auth.unchained == 1
 assert auth.nonce < 2**64
 assert len(auth.address) == 20
 assert auth.y_parity < 2**8
@@ -66,17 +63,19 @@ The [EIP-2718](./eip-2718.md) `ReceiptPayload` for this transaction is `rlp([sta
 
 At the start of executing the transaction, after incrementing the sender's nonce, for each `[chain_id, address, nonce, y_parity, r, s]` tuple do the following:
 
-1. Verify the chain id is either 0 or the chain's current ID.
+1. Establish signed-over chain ID of the authorization.
+    * 1a. If `unchained` is zero, set `auth_chain_id` to the transaction `chain_id` (which must equal the executing chain's ID).
+    * 1b. If `unchained` is one, set `auth_chain_id` to zero.
 2. Verify the `nonce` is less than `2**64 - 1`.
-3. `authority = ecrecover(keccak(MAGIC || rlp([chain_id, address, nonce])), y_parity, r, s]`
-    * `s` value must be less than or equal to `secp256k1n/2`, as specified in [EIP-2](./eip-2.md).
+3. `authority = ecrecover(keccak(MAGIC || rlp([auth_chain_id, address, nonce])), y_parity, r, s]`
+    * 3a. The `s` value must be less than or equal to `secp256k1n/2`, as specified in [EIP-2](./eip-2.md).
 4. Add `authority` to `accessed_addresses` (as defined in [EIP-2929](./eip-2929.md).)
-5. Verify the code of `authority` is either empty or already delegated.
+5. Verify the code of the `authority` account is either empty or already delegated.
 6. Verify the nonce of `authority` is equal to `nonce`. In case `authority` does not exist in the trie, verify that `nonce` is equal to `0`.
 7. Add `PER_EMPTY_ACCOUNT_COST - PER_AUTH_BASE_COST` gas to the global refund counter if `authority` exists in the trie.
 8. Set the code of `authority` to be `0xef0100 || address`. This is a delegation designation. 
-    * As a special case, if `address` is `0x0000000000000000000000000000000000000000` do not write the designation. Clear the account's code and reset the account's code hash to the empty hash `0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470`.
-9. Increase the nonce of `authority` by one.
+    * 8a. As a special case, if `address` is `0x0000000000000000000000000000000000000000` do not write the designation. Clear the account's code and reset the account's code hash to the empty hash `0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470`.
+9. Increase the nonce of the `authority` account by one.
 
 If any of the above steps fail, immediately stop processing that tuple and continue to the next tuple in the list. It will in the case of multiple tuples for the same authority, set the code using the address in the last valid occurrence.