bigchain/core: multisig

interledger: user, escrow, connector

bigchaindb/core.py

@@ -68,7 +68,7 @@ class Bigchain(object):
     def reconnect(self):
         return r.connect(host=self.host, port=self.port, db=self.dbname)
 
-    def create_transaction(self, current_owner, new_owner, tx_input, operation, payload=None):
+    def create_transaction(self, current_owners, new_owners, tx_input, operation, payload=None):
         """Create a new transaction
 
         A transaction in the bigchain is a transfer of a digital asset between two entities represented
@@ -84,8 +84,8 @@ class Bigchain(object):
             `TRANSFER` - A transfer operation allows for a transfer of the digital assets between entities.
 
         Args:
-            current_owner (str): base58 encoded public key of the current owner of the asset.
-            new_owner (str): base58 encoded public key of the new owner of the digital asset.
+            current_owners (list): base58 encoded public keys of all current owners of the asset.
+            new_owners (list): base58 encoded public keys of all new owners of the digital asset.
             tx_input (str): id of the transaction to use as input.
             operation (str): Either `CREATE` or `TRANSFER` operation.
             payload (Optional[dict]): dictionary with information about asset.
@@ -115,8 +115,8 @@ class Bigchain(object):
         }
 
         tx = {
-            'current_owner': current_owner,
-            'new_owner': new_owner,
+            'current_owners': current_owners if isinstance(current_owners, list) else [current_owners],
+            'new_owners': new_owners if isinstance(new_owners, list) else [new_owners],
             'input': tx_input,
             'operation': operation,
             'timestamp': self.timestamp(),
@@ -135,7 +135,7 @@ class Bigchain(object):
 
         return transaction
 
-    def sign_transaction(self, transaction, private_key):
+    def sign_transaction(self, transaction, private_key, public_key=None):
         """Sign a transaction
 
         A transaction signed with the `current_owner` corresponding private key.
@@ -143,15 +143,28 @@ class Bigchain(object):
         Args:
             transaction (dict): transaction to sign.
             private_key (str): base58 encoded private key to create a signature of the transaction.
-
+            public_key (str): (optional) base58 encoded public key to identify each signature of a multisig transaction.
         Returns:
             dict: transaction with the `signature` field included.
 
         """
         private_key = PrivateKey(private_key)
-        signature = private_key.sign(self.serialize(transaction))
+        if len(transaction['transaction']['current_owners']) == 1:
+            signatures_updated = private_key.sign(self.serialize(transaction))
+        else:
+            # multisig, sign for each input and store {pub_key: signature_for_priv_key}
+            if public_key is None:
+                raise ValueError('public_key must be provided for signing multisig transactions')
+            transaction_without_signatures = transaction.copy()
+            signatures = transaction_without_signatures.pop('signatures') \
+                if 'signatures' in transaction_without_signatures else []
+            signatures_updated = signatures.copy()
+            signatures_updated = [s for s in signatures_updated if not s['public_key'] == public_key]
+            signatures_updated.append({'public_key': public_key,
+                                       'signature': private_key.sign(self.serialize(transaction_without_signatures))})
+
         signed_transaction = transaction.copy()
-        signed_transaction.update({'signature': signature})
+        signed_transaction.update({'signatures': signatures_updated})
         return signed_transaction
 
     def verify_signature(self, signed_transaction):
@@ -172,10 +185,23 @@ class Bigchain(object):
         if 'assignee' in data:
             data.pop('assignee')
 
-        signature = data.pop('signature')
-        public_key_base58 = signed_transaction['transaction']['current_owner']
+        signatures = data.pop('signatures')
+        for public_key_base58 in signed_transaction['transaction']['current_owners']:
             public_key = PublicKey(public_key_base58)
-        return public_key.verify(self.serialize(data), signature)
+
+            if isinstance(signatures, list):
+                try:
+                    signature = [s['signature'] for s in signatures if s['public_key'] == public_key_base58]
+                except KeyError:
+                    return False
+                if not len(signature) == 1:
+                    return False
+                signature = signature[0]
+            else:
+                signature = signatures
+            if not public_key.verify(self.serialize(data), signature):
+                return False
+        return True
 
     def write_transaction(self, signed_transaction):
         """Write the transaction to bigchain.
@@ -184,7 +210,7 @@ class Bigchain(object):
         it has been validated by the nodes of the federation.
 
         Args:
-            singed_transaction (dict): transaction with the `signature` included.
+            signed_transaction (dict): transaction with the `signature` included.
 
         Returns:
             dict: database response
@@ -299,9 +325,10 @@ class Bigchain(object):
             list: list of `txids` currently owned by `owner`
 
         """
+        # TODO: fix for multisig. new_owners is a list!
         response = r.table('bigchain')\
                     .concat_map(lambda doc: doc['block']['transactions'])\
-                    .filter({'transaction': {'new_owner': owner}})\
+                    .filter({'transaction': {'new_owners': owner if isinstance(owner, list) else [owner]}})\
                     .pluck('id')['id']\
                     .run(self.conn)
         owned = []
@@ -336,7 +363,7 @@ class Bigchain(object):
         if transaction['transaction']['operation'] == 'CREATE':
             if transaction['transaction']['input']:
                 raise ValueError('A CREATE operation has no inputs')
-            if transaction['transaction']['current_owner'] not in self.federation_nodes + [self.me]:
+            if not(set(transaction['transaction']['current_owners']) <= set(self.federation_nodes + [self.me])):
                 raise exceptions.OperationError('Only federation nodes can use the operation `CREATE`')
 
         else:
@@ -349,9 +376,9 @@ class Bigchain(object):
                 raise exceptions.TransactionDoesNotExist('input `{}` does not exist in the bigchain'.format(
                     transaction['transaction']['input']))
 
-            if tx_input['transaction']['new_owner'] != transaction['transaction']['current_owner']:
+            if tx_input['transaction']['new_owners'] != transaction['transaction']['current_owners']:
                 raise exceptions.TransactionOwnerError('current_owner `{}` does not own the input `{}`'.format(
-                    transaction['transaction']['current_owner'], transaction['transaction']['input']))
+                    transaction['transaction']['current_owners'], transaction['transaction']['input']))
 
             # check if the input was already spent
             spent = self.get_spent(tx_input['id'])
@@ -496,13 +523,11 @@ class Bigchain(object):
         # 2. create the block with one transaction
         # 3. write the block to the bigchain
 
-
         blocks_count = r.table('bigchain').count().run(self.conn)
 
         if blocks_count:
             raise GenesisBlockAlreadyExistsError('Cannot create the Genesis block')
 
-
         payload = {'message': 'Hello World from the Bigchain'}
         transaction = self.create_transaction(self.me, self.me, None, 'GENESIS', payload=payload)
         transaction_signed = self.sign_transaction(transaction, self.me_private)

interledger/core.py

@@ -0,0 +1,120 @@
+
+
+class User:
+    def __init__(self, ledger):
+        self.ledger = ledger
+        self.private, self.public = ledger.generate_keys()
+        self.assets = []
+
+    def create_asset(self):
+        tx = self.ledger.create_transaction(self.ledger.me, self.public, None, 'CREATE')
+        tx_signed = self.ledger.sign_transaction(tx, self.ledger.me_private)
+        self.ledger.validate_transaction(tx_signed)
+        self.ledger.write_transaction(tx_signed)
+        self.assets.append(tx_signed)
+
+    def create_assets(self, amount=1):
+        for i in range(amount):
+            self.create_asset()
+
+
+class Escrow(User):
+    def __init__(self, ledger=None, current_owner=None, new_owner=None,
+                 asset_id=None, condition_func=None, payload=None):
+        User.__init__(self, ledger)
+        self.condition_func = condition_func if condition_func else lambda proof: True
+        self.new_owner = new_owner
+        tx = self.ledger.create_transaction(current_owner,
+                                            [current_owner, self.public],
+                                            asset_id,
+                                            'TRANSFER',
+                                            payload)
+        self.assets = tx
+
+    def release(self, receipt=None):
+        if not self.validate(receipt):
+            raise Exception
+        tx = self.ledger.create_transaction(self.assets['transaction']['new_owners'],
+                                            self.new_owner,
+                                            self.assets['id'],
+                                            'TRANSFER',
+                                            self.assets['transaction']['data']['payload'])
+        return self.ledger.sign_transaction(tx, self.private, self.public)
+
+    def validate(self, receipt):
+        return self.condition_func(receipt)
+
+
+class LedgerConnection(User):
+    def __init__(self, ledger):
+        self._escrow = None
+        User.__init__(self, ledger)
+
+    def escrow(self, current_owner=None, new_owner=None, condition_func=None, asset_id=None, payload=None):
+        self._escrow = Escrow(ledger=self.ledger,
+                              current_owner=current_owner if current_owner else self.public,
+                              new_owner=new_owner if new_owner else self.public,
+                              asset_id=asset_id if asset_id else self.assets[0]['id'],
+                              condition_func=condition_func,
+                              payload=payload)
+        if not current_owner:
+            tx_connector_signed = self.ledger.sign_transaction(self._escrow.assets, self.private)
+            self.ledger.validate_transaction(tx_connector_signed)
+            self._escrow.assets = tx_connector_signed
+            self.ledger.write_transaction(tx_connector_signed)
+
+    def release(self, condition):
+        return self._escrow.release(condition)
+
+
+class Connector:
+    def __init__(self, ledger=None):
+        self.ledger_connections = []
+        if ledger:
+            self.add_ledger(ledger)
+
+    def public(self, ledger=None):
+        return self.get_ledger_connection(ledger).public if self.get_ledger_connection(ledger) else None
+
+    def private(self, ledger=None):
+        return self.get_ledger_connection(ledger).private if self.get_ledger_connection(ledger) else None
+
+    def get_assets(self, ledger=None):
+        ledger_connection = self.get_ledger_connection(ledger)
+        return ledger_connection.assets if ledger_connection else None
+
+    def create_assets(self, amount=1, ledger=None):
+        ledger_connection = self.get_ledger_connection(ledger)
+        if ledger_connection:
+            ledger_connection.create_assets(amount)
+
+    def get_ledger_connection(self, ledger=None):
+        if not ledger:
+            return self.ledger_connections[0]
+        # TODO: yield
+        ledger_connection = [l for l in self.ledger_connections if l.ledger == ledger]
+        return ledger_connection[0] if ledger_connection else None
+
+    def add_ledger(self, ledger):
+        if self.can_add_ledger_connection(ledger):
+            self.ledger_connections.append(LedgerConnection(ledger))
+
+    def can_add_ledger_connection(self, ledger):
+        return False if self.get_ledger_connection(ledger) else True
+
+    def connect(self, user_from=None, ledger_from=None, user_to=None, ledger_to=None,
+                condition_func=None, asset_id=None, payload=None):
+        connection_from = self.get_ledger_connection(ledger_from)
+        connection_to = self.get_ledger_connection(ledger_to)
+        connection_from.escrow(current_owner=user_from,
+                               condition_func=condition_func,
+                               asset_id=asset_id,
+                               payload=payload)
+        connection_to.escrow(new_owner=user_to,
+                             condition_func=condition_func,
+                             payload=payload)
+        return connection_from._escrow.assets
+
+    def release(self, ledger=None, receipt=None):
+        connection = self.get_ledger_connection(ledger)
+        return connection.release(receipt)

interledger/tests/bigchain.json

@@ -0,0 +1 @@
+{"database": {"host": "localhost", "name": "bigchain", "port": 28015}, "keyring": [], "keypair": {"public": "jhpCiHPiMmHGFQvjqn1LdLddYhYFd63ywUbi3tFCW31f", "private": "5vbka7oLMf2UTNV1sq3nyKJXTERCPWvD8Pf4KnGYNBtA"}}

interledger/tests/megachain.json

@@ -0,0 +1 @@
+{"keyring": [], "database": {"host": "localhost", "port": 28015, "name": "megachain"}, "keypair": {"private": "DGKiLSdLsZofmzZMv3B9KZVj79wrq4PZ3PsMmk8Hu8KK", "public": "gMGJ9j15qyBVC1t8ceiDgJLLaRBgvrFchyzB1GgWk3Fa"}}

interledger/tests/test_connector.py

@@ -0,0 +1,53 @@
+import json
+from time import sleep
+
+from bigchaindb import Bigchain
+from interledger.core import User, Connector
+
+config_bigchain = json.load(open('interledger/tests/bigchain.json', 'r'))
+config_megachain = json.load(open('interledger/tests/megachain.json', 'r'))
+
+bigchain = Bigchain(dbname=config_bigchain['database']['name'],
+                    public_key=config_bigchain['keypair']['public'],
+                    private_key=config_bigchain['keypair']['private'])
+
+megachain = Bigchain(dbname=config_megachain['database']['name'],
+                     public_key=config_megachain['keypair']['public'],
+                     private_key=config_megachain['keypair']['private'])
+
+alice = User(bigchain)
+bob = User(megachain)
+
+connector = Connector(bigchain)
+connector.add_ledger(megachain)
+
+# create assets
+alice.create_assets(amount=2)
+connector.create_assets(amount=2, ledger=bigchain)
+connector.create_assets(amount=2, ledger=megachain)
+
+sleep(6)
+# transfer asset to escrow
+tx_alice = connector.connect(user_from=alice.public,
+                             ledger_from=alice.ledger,
+                             user_to=bob.public,
+                             ledger_to=bob.ledger,
+                             condition_func=lambda proof: True,
+                             asset_id=alice.assets[0]['id'],
+                             payload={'what': 'ever'})
+
+tx_alice_signed = alice.ledger.sign_transaction(tx_alice, alice.private)
+alice.ledger.validate_transaction(tx_alice_signed)
+alice.ledger.write_transaction(tx_alice_signed)
+
+sleep(6)
+# release asset from escrow
+tx_bob = connector.release(ledger=bob.ledger, receipt=None)
+tx_bob_signed = bob.ledger.sign_transaction(tx_bob, connector.private(bob.ledger), connector.public(bob.ledger))
+bob.ledger.validate_transaction(tx_bob_signed)
+bob.ledger.write_transaction(tx_bob_signed)
+
+tx_connector = connector.release(ledger=alice.ledger, receipt=None)
+tx_connector_signed = alice.ledger.sign_transaction(tx_connector, alice.private, alice.public)
+alice.ledger.validate_transaction(tx_connector_signed)
+alice.ledger.write_transaction(tx_connector_signed)