Update EIP-7002: convert to use 7685 requests (#8469)

Author: lightclient

EIPS/eip-7002.md

@@ -8,6 +8,7 @@ status: Draft
 type: Standards Track
 category: Core
 created: 2023-05-09
+requires: 7685
 ---
 
 ## Abstract
@@ -39,6 +40,7 @@ Note, 0x00 withdrawal credentials can be changed into 0x01 withdrawal credential
 | Name | Value | Comment |
 | - | - | - |
 | `WITHDRAWAL_REQUEST_PREDEPLOY_ADDRESS` | `0xEd8EA01d70Cb49726175BCf2778B9C982912e017` | Where to call and store relevant details about exit / partial withdrawal mechanism |
+| `WITHDRAWAL_REQUEST_TYPE` | `0x01` | The [EIP-7685](./eip-7685.md) type prefix for withdrawal request |
 | `SYSTEM_ADDRESS` | `0xfffffffffffffffffffffffffffffffffffffffe` | Address used to invoke system operation on contract
 | `EXCESS_WITHDRAWAL_REQUESTS_STORAGE_SLOT` | 0 | |
 | `WITHDRAWAL_REQUEST_COUNT_STORAGE_SLOT` | 1 | |
@@ -58,20 +60,17 @@ Note, 0x00 withdrawal credentials can be changed into 0x01 withdrawal credential
 
 #### Withdrawal request operation
 
-The new withdrawal request operation consists of the following fields:
+The new withdrawal request operation is an [EIP-7685](./eip-7685.md) request
+with type `0x01` and consists of the following fields:
 
 1. `source_address`: `Bytes20`
 2. `validator_pubkey`: `Bytes48`
 3. `amount:` `uint64`
 
-RLP encoding of a withdrawal request **MUST** be computed as the following:
+The [EIP-7685](./eip-7685) encoding of a withdrawal request **MUST** be computed as the follows:
 
 ```python
-rlp_encoded_withdrawal_request = RLP([
-    source_address,
-    validator_pubkey,
-    amount
-])
+encoded = WITHDRAWAL_REQUEST_TYPE ++ rlp([source_address, validator_pubkey, amount])
 ```
 
 #### Withdrawal Request Contract
@@ -225,7 +224,7 @@ def reset_withdrawal_requests_count():
     sstore(WITHDRAWAL_REQUEST_PREDEPLOY_ADDRESS, WITHDRAWAL_REQUEST_COUNT_STORAGE_SLOT, 0)
 ```
 
-#### Bytecode
+##### Bytecode
 
 ```asm
 caller
@@ -469,7 +468,7 @@ push0
 revert
 ```
 
-#### Deployment
+##### Deployment
 
 The withdrawal requests contract is deployed like any other smart contract. A special synthetic address is generated by working backwards from the desired deployment transaction:
 
@@ -496,31 +495,6 @@ Sender: 0x3da359dC1d98B53f32848dFfDC421410a47bbBD5
 Address: 0xEd8EA01d70Cb49726175BCf2778B9C982912e017
 ```
 
-#### Block structure
-
-Beginning with the `FORK_BLOCK`, the block body **MUST** be appended with the list of withdrawal requests returned by `read_withdrawal_requests()`. RLP encoding of the extended block body structure **MUST** be computed as follows:
-
-```python
-block_body_rlp = RLP([
-    field_0,
-    ...,
-    # Latest block body field before `withdrawal_requests`
-    field_n,
-
-    [req_0, ..., req_k],
-])
-```
-
-Beginning with the `FORK_BLOCK`, the block header **MUST** be appended with the new **`withdrawal_requests_root`** field. The value of this field is the trie root committing to the list of requests in the block body. **`withdrawal_requests_root`** field value **MUST** be computed as follows:
-
-```python
-def compute_trie_root_from_indexed_data(data):
-    trie = Trie.from([(i, obj) for i, obj in enumerate(data)])
-    return trie.root
-
-block.header.withdrawal_requests_root = compute_trie_root_from_indexed_data(block.body.withdrawa_requests)
-```
-
 ### Consensus layer
 
 [Full specification](https://github.com/ethereum/consensus-specs/blob/7bf43d1bc4fdb91059f0e6f4f7f0f3349b144950/specs/electra/beacon-chain.md)