Merge pull request #780 from ethereum/JustinDrake-patch-7

Simplify deposits

specs/core/0_beacon-chain.md

@@ -29,7 +29,6 @@
             - [`AttestationData`](#attestationdata)
             - [`AttestationDataAndCustodyBit`](#attestationdataandcustodybit)
             - [`SlashableAttestation`](#slashableattestation)
-            - [`DepositInput`](#depositinput)
             - [`DepositData`](#depositdata)
             - [`BeaconBlockHeader`](#beaconblockheader)
             - [`Validator`](#validator)
@@ -384,7 +383,7 @@ The types are defined topologically to aid in facilitating an executable version
 }
 ```
 
-#### `DepositInput`
+#### `DepositData`
 
 ```python
 {
@@ -392,21 +391,10 @@ The types are defined topologically to aid in facilitating an executable version
     'pubkey': 'bytes48',
     # Withdrawal credentials
     'withdrawal_credentials': 'bytes32',
-    # A BLS signature of this `DepositInput`
-    'proof_of_possession': 'bytes96',
-}
-```
-
-#### `DepositData`
-
-```python
-{
     # Amount in Gwei
     'amount': 'uint64',
-    # Timestamp from deposit contract
+    # Container self-signature
-    'timestamp': 'uint64',
+    'proof_of_possession': 'bytes96',
-    # Deposit input
-    'deposit_input': DepositInput,
 }
 ```
 
@@ -520,7 +508,7 @@ The types are defined topologically to aid in facilitating an executable version
     # Index in the deposit tree
     'index': 'uint64',
     # Data
-    'deposit_data': DepositData,
+    'data': DepositData,
 }
 ```
 
@@ -1340,19 +1328,12 @@ def process_deposit(state: BeaconState, deposit: Deposit) -> None:
     Process a deposit from Ethereum 1.0.
     Note that this function mutates ``state``.
     """
-    deposit_input = deposit.deposit_data.deposit_input
-
-    # Should equal 8 bytes for deposit_data.amount +
-    #              8 bytes for deposit_data.timestamp +
-    #              176 bytes for deposit_data.deposit_input
-    # It should match the deposit_data in the eth1.0 deposit contract
-    serialized_deposit_data = serialize(deposit.deposit_data)
     # Deposits must be processed in order
     assert deposit.index == state.deposit_index
 
     # Verify the Merkle branch
     merkle_branch_is_valid = verify_merkle_branch(
-        leaf=hash(serialized_deposit_data),
+        leaf=hash(serialize(deposit.data)),  # 48 + 32 + 8 + 96 = 184 bytes serialization
         proof=deposit.proof,
         depth=DEPOSIT_CONTRACT_TREE_DEPTH,
         index=deposit.index,
@@ -1367,16 +1348,15 @@ def process_deposit(state: BeaconState, deposit: Deposit) -> None:
     state.deposit_index += 1
 
     validator_pubkeys = [v.pubkey for v in state.validator_registry]
-    pubkey = deposit_input.pubkey
+    pubkey = deposit.data.pubkey
-    amount = deposit.deposit_data.amount
+    amount = deposit.data.amount
-    withdrawal_credentials = deposit_input.withdrawal_credentials
 
     if pubkey not in validator_pubkeys:
         # Verify the proof of possession
         proof_is_valid = bls_verify(
-            pubkey=deposit_input.pubkey,
+            pubkey=pubkey,
-            message_hash=signed_root(deposit_input),
+            message_hash=signed_root(deposit.data),
-            signature=deposit_input.proof_of_possession,
+            signature=deposit.data.proof_of_possession,
             domain=get_domain(
                 state.fork,
                 get_current_epoch(state),
@@ -1389,7 +1369,7 @@ def process_deposit(state: BeaconState, deposit: Deposit) -> None:
         # Add new validator
         validator = Validator(
             pubkey=pubkey,
-            withdrawal_credentials=withdrawal_credentials,
+            withdrawal_credentials=deposit.data.withdrawal_credentials,
             activation_epoch=FAR_FUTURE_EPOCH,
             exit_epoch=FAR_FUTURE_EPOCH,
             withdrawable_epoch=FAR_FUTURE_EPOCH,
@@ -1491,11 +1471,11 @@ The initial deployment phases of Ethereum 2.0 are implemented without consensus
 
 ### Deposit arguments
 
-The deposit contract has a single `deposit` function which takes as argument a SimpleSerialize'd `DepositInput`.
+The deposit contract has a single `deposit` function which takes as argument a SimpleSerialize'd `DepositData`.
 
 ### Withdrawal credentials
 
-One of the `DepositInput` fields is `withdrawal_credentials`. It is a commitment to credentials for withdrawals to shards. The first byte of `withdrawal_credentials` is a version number. As of now the only expected format is as follows:
+One of the `DepositData` fields is `withdrawal_credentials`. It is a commitment to credentials for withdrawals to shards. The first byte of `withdrawal_credentials` is a version number. As of now the only expected format is as follows:
 
 * `withdrawal_credentials[:1] == BLS_WITHDRAWAL_PREFIX_BYTE`
 * `withdrawal_credentials[1:] == hash(withdrawal_pubkey)[1:]` where `withdrawal_pubkey` is a BLS pubkey

tests/phase0/helpers.py

@@ -12,7 +12,6 @@ from build.phase0.spec import (
     AttestationData,
     BeaconBlockHeader,
     Deposit,
-    DepositInput,
     DepositData,
     Eth1Data,
     ProposerSlashing,
@@ -43,21 +42,17 @@ pubkey_to_privkey = {pubkey: privkey for privkey, pubkey in zip(privkeys, pubkey
 def create_mock_genesis_validator_deposits(num_validators, deposit_data_leaves=None):
     if not deposit_data_leaves:
         deposit_data_leaves = []
-    deposit_timestamp = 0
     proof_of_possession = b'\x33' * 96
 
     deposit_data_list = []
     for i in range(num_validators):
         pubkey = pubkeys[i]
         deposit_data = DepositData(
+            pubkey=pubkey,
+            # insecurely use pubkey as withdrawal key as well
+            withdrawal_credentials=spec.BLS_WITHDRAWAL_PREFIX_BYTE + hash(pubkey)[1:],
             amount=spec.MAX_DEPOSIT_AMOUNT,
-            timestamp=deposit_timestamp,
+            proof_of_possession=proof_of_possession,
-            deposit_input=DepositInput(
-                pubkey=pubkey,
-                # insecurely use pubkey as withdrawal key as well
-                withdrawal_credentials=spec.BLS_WITHDRAWAL_PREFIX_BYTE + hash(pubkey)[1:],
-                proof_of_possession=proof_of_possession,
-            ),
         )
         item = hash(deposit_data.serialize())
         deposit_data_leaves.append(item)
@@ -72,7 +67,7 @@ def create_mock_genesis_validator_deposits(num_validators, deposit_data_leaves=N
         genesis_validator_deposits.append(Deposit(
             proof=list(get_merkle_proof(tree, item_index=i)),
             index=i,
-            deposit_data=deposit_data_list[i]
+            data=deposit_data_list[i]
         ))
     return genesis_validator_deposits, root
 
@@ -112,14 +107,15 @@ def build_empty_block_for_next_slot(state):
 
 
 def build_deposit_data(state, pubkey, privkey, amount):
-    deposit_input = DepositInput(
+    deposit_data = DepositData(
         pubkey=pubkey,
         # insecurely use pubkey as withdrawal key as well
         withdrawal_credentials=spec.BLS_WITHDRAWAL_PREFIX_BYTE + hash(pubkey)[1:],
+        amount=amount,
         proof_of_possession=EMPTY_SIGNATURE,
     )
     proof_of_possession = bls.sign(
-        message_hash=signed_root(deposit_input),
+        message_hash=signed_root(deposit_data),
         privkey=privkey,
         domain=get_domain(
             state.fork,
@@ -127,12 +123,7 @@ def build_deposit_data(state, pubkey, privkey, amount):
             spec.DOMAIN_DEPOSIT,
         )
     )
-    deposit_input.proof_of_possession = proof_of_possession
+    deposit_data.proof_of_possession = proof_of_possession
-    deposit_data = DepositData(
-        amount=amount,
-        timestamp=0,
-        deposit_input=deposit_input,
-    )
     return deposit_data
 
 
@@ -201,7 +192,7 @@ def build_deposit(state,
     deposit = Deposit(
         proof=list(proof),
         index=index,
-        deposit_data=deposit_data,
+        data=deposit_data,
     )
 
     return deposit, root, deposit_data_leaves

tests/phase0/test_sanity.py

@@ -163,7 +163,7 @@ def test_deposit_in_block(state):
     deposit = Deposit(
         proof=list(proof),
         index=index,
-        deposit_data=deposit_data,
+        data=deposit_data,
     )
 
     pre_state.latest_eth1_data.deposit_root = root
@@ -202,7 +202,7 @@ def test_deposit_top_up(state):
     deposit = Deposit(
         proof=list(proof),
         index=merkle_index,
-        deposit_data=deposit_data,
+        data=deposit_data,
     )
 
     pre_state.latest_eth1_data.deposit_root = root