Move some other code to the util module

bigchaindb/core.py

@@ -8,7 +8,7 @@ import bigchaindb
 from bigchaindb import util
 from bigchaindb import config_utils
 from bigchaindb import exceptions
-from bigchaindb.crypto import hash_data, PublicKey, PrivateKey, generate_key_pair
+from bigchaindb import crypto
 
 
 class GenesisBlockAlreadyExistsError(Exception):
@@ -80,15 +80,9 @@ class Bigchain(object):
         return util.sign_tx(transaction, private_key)
 
     def verify_signature(self, signed_transaction):
-        """Verify the signature of a transaction
+        """Verify the signature of a transaction.
 
-        A valid transaction should have been signed `current_owner` corresponding private key.
-
-        Args:
-            signed_transaction (dict): a transaction with the `signature` included.
-
-        Returns:
-            bool: True if the signature is correct, False otherwise.
+        Refer to the documentation of ``bigchaindb.crypto.verify_signature``
         """
 
         data = signed_transaction.copy()
@@ -99,7 +93,7 @@ class Bigchain(object):
 
         signature = data.pop('signature')
         public_key_base58 = signed_transaction['transaction']['current_owner']
-        public_key = PublicKey(public_key_base58)
+        public_key = crypto.PublicKey(public_key_base58)
         return public_key.verify(util.serialize(data), signature)
 
     def write_transaction(self, signed_transaction):
@@ -284,15 +278,7 @@ class Bigchain(object):
                 raise exceptions.DoubleSpend('input `{}` was already spent'.format(
                     transaction['transaction']['input']))
 
-        # Check hash of the transaction
-        calculated_hash = hash_data(util.serialize(transaction['transaction']))
-        if calculated_hash != transaction['id']:
-            raise exceptions.InvalidHash()
-
-        # Check signature
-        if not self.verify_signature(transaction):
-            raise exceptions.InvalidSignature()
-
+        util.check_hash_and_signature(transaction)
         return transaction
 
     def is_valid_transaction(self, transaction):
@@ -338,8 +324,8 @@ class Bigchain(object):
 
         # Calculate the hash of the new block
         block_data = util.serialize(block)
-        block_hash = hash_data(block_data)
-        block_signature = PrivateKey(self.me_private).sign(block_data)
+        block_hash = util.hash_data(block_data)
+        block_signature = crypto.PrivateKey(self.me_private).sign(block_data)
 
         block = {
             'id': block_hash,
@@ -363,7 +349,7 @@ class Bigchain(object):
         """
 
         # 1. Check if current hash is correct
-        calculated_hash = hash_data(util.serialize(block['block']))
+        calculated_hash = util.hash_data(util.serialize(block['block']))
         if calculated_hash != block['id']:
             raise exceptions.InvalidHash()
 
@@ -459,7 +445,7 @@ class Bigchain(object):
         }
 
         vote_data = util.serialize(vote)
-        signature = PrivateKey(self.me_private).sign(vote_data)
+        signature = crypto.PrivateKey(self.me_private).sign(vote_data)
 
         vote_signed = {
             'node_pubkey': self.me,
@@ -541,4 +527,4 @@ class Bigchain(object):
         """
 
         # generates and returns the keys serialized in hex
-        return generate_key_pair()
+        return crypto.generate_key_pair()

bigchaindb/crypto.py

@@ -1,7 +1,5 @@
 # Separate all crypto code so that we can easily test several implementations
 
-import hashlib
-import sha3
 import binascii
 import base58
 import bitcoin
@@ -146,6 +144,3 @@ def generate_key_pair():
 
     return (private_value_base58, public_value_compressed_base58)
 
-
-def hash_data(data):
-    return hashlib.sha3_256(data.encode()).hexdigest()

bigchaindb/util.py

@@ -1,9 +1,12 @@
-import multiprocessing as mp
+import sha3
+
 import json
 import time
+import multiprocessing as mp
 from datetime import datetime
 
-from bigchaindb.crypto import hash_data, PrivateKey
+from bigchaindb import exceptions
+from bigchaindb.crypto import PrivateKey, PublicKey
 
 
 class ProcessGroup(object):
@@ -148,3 +151,47 @@ def sign_tx(transaction, private_key):
     signed_transaction.update({'signature': signature})
     return signed_transaction
 
+
+def create_and_sign_tx(private_key, current_owner, new_owner, tx_input, operation='TRANSFER', payload=None):
+    tx = create_tx(current_owner, new_owner, tx_input, operation, payload)
+    return sign_tx(private_key, tx)
+
+
+def hash_data(data):
+    return sha3.sha3_256(data.encode()).hexdigest()
+
+
+def check_hash_and_signature(transaction):
+    # Check hash of the transaction
+    calculated_hash = hash_data(serialize(transaction['transaction']))
+    if calculated_hash != transaction['id']:
+        raise exceptions.InvalidHash()
+
+    # Check signature
+    if not verify_signature(transaction):
+        raise exceptions.InvalidSignature()
+
+
+def verify_signature(signed_transaction):
+    """Verify the signature of a transaction
+
+    A valid transaction should have been signed `current_owner` corresponding private key.
+
+    Args:
+        signed_transaction (dict): a transaction with the `signature` included.
+
+    Returns:
+        bool: True if the signature is correct, False otherwise.
+    """
+
+    data = signed_transaction.copy()
+
+    # if assignee field in the transaction, remove it
+    if 'assignee' in data:
+        data.pop('assignee')
+
+    signature = data.pop('signature')
+    public_key_base58 = signed_transaction['transaction']['current_owner']
+    public_key = PublicKey(public_key_base58)
+    return public_key.verify(serialize(data), signature)
+

tests/db/test_bigchain_api.py

@@ -8,7 +8,8 @@ import rethinkdb as r
 import bigchaindb
 from bigchaindb import util
 from bigchaindb import exceptions
-from bigchaindb.crypto import hash_data, PrivateKey, PublicKey, generate_key_pair
+from bigchaindb.crypto import PrivateKey, PublicKey, generate_key_pair
+from bigchaindb.util import hash_data
 from bigchaindb.voter import Voter
 from bigchaindb.block import Block