def threshold_it():
#gets input data
data = request.get_json(force=True)
txID = data['txID']
cid = int(data['cid'])
pubKeys = data['pubKeys']
privKeys = data['privKeys']
newPubKeys = data['newPubKeys']
N = int(data['N'])
#formats input data
pubKeys = pubKeys.split("_")
privKeys = privKeys.split("_")
newPubKeys = newPubKeys.split("_")
#format retrieved_id
txn = {"cid": cid, "txid": txID}
#makes the base template
threshold_tx = b.create_transaction(pubKeys, newPubKeys, txn, 'TRANSFER')
#implements the threshold condition
threshold_condition = cc.ThresholdSha256Fulfillment(threshold=(N))
for i in range(len(newPubKeys)):
threshold_condition.add_subfulfillment(
cc.Ed25519Fulfillment(public_key=newPubKeys[i]))
#Update the condition in the newly created transaction
threshold_tx['transaction']['conditions'][0]['condition'] = {
'details': json.loads(threshold_condition.serialize_json()),
'uri': threshold_condition.condition.serialize_uri()
}
#Now update the transaction hash (ID)
threshold_tx['id'] = util.get_hash_data(threshold_tx)
#Sign the transaction
threshold_tx_signed = b.sign_transaction(threshold_tx, privKeys)
#Write the transaction
b.write_transaction(threshold_tx_signed)
#Return the signed transaction
return flask.jsonify(**threshold_tx_signed)
def create_tx(current_owners, new_owners, inputs, operation, payload=None):
"""Create a new transaction
A transaction in the bigchain is a transfer of a digital asset between two entities represented
by public keys.
Currently the bigchain supports two types of operations:
`CREATE` - Only federation nodes are allowed to use this operation. In a create operation
a federation node creates a digital asset in the bigchain and assigns that asset to a public
key. The owner of the private key can then decided to transfer this digital asset by using the
`transaction id` of the transaction as an input in a `TRANSFER` transaction.
`TRANSFER` - A transfer operation allows for a transfer of the digital assets between entities.
Args:
current_owners (list): base58 encoded public key of the current owners of the asset.
new_owners (list): base58 encoded public key of the new owners of the digital asset.
inputs (list): id of the transaction to use as input.
operation (str): Either `CREATE` or `TRANSFER` operation.
payload (Optional[dict]): dictionary with information about asset.
Returns:
dict: unsigned transaction.
Raises:
TypeError: if the optional ``payload`` argument is not a ``dict``.
Reference:
{
"id": "<sha3 hash>",
"version": "transaction version number",
"transaction": {
"fulfillments": [
{
"current_owners": ["list of <pub-keys>"],
"input": {
"txid": "<sha3 hash>",
"cid": "condition index"
},
"fulfillment": "fulfillement of condition cid",
"fid": "fulfillment index"
}
],
"conditions": [
{
"new_owners": ["list of <pub-keys>"],
"condition": "condition to be met",
"cid": "condition index (1-to-1 mapping with fid)"
}
],
"operation": "<string>",
"timestamp": "<timestamp from client>",
"data": {
"hash": "<SHA3-256 hash hexdigest of payload>",
"payload": {
"title": "The Winds of Plast",
"creator": "Johnathan Plunkett",
"IPFS_key": "QmfQ5QAjvg4GtA3wg3adpnDJug8ktA1BxurVqBD8rtgVjP"
}
}
},
}
"""
# validate arguments (owners and inputs should be lists or None)
# The None case appears on fulfilling a hashlock
if current_owners is None:
current_owners = []
if not isinstance(current_owners, list):
current_owners = [current_owners]
# The None case appears on assigning a hashlock
if new_owners is None:
new_owners = []
if not isinstance(new_owners, list):
new_owners = [new_owners]
if not isinstance(inputs, list):
inputs = [inputs]
# handle payload
if payload is not None and not isinstance(payload, dict):
raise TypeError('`payload` must be an dict instance or None')
data = {'uuid': str(uuid.uuid4()), 'payload': payload}
# handle inputs
fulfillments = []
# transfer
if inputs:
for fid, tx_input in enumerate(inputs):
fulfillments.append({
'current_owners': current_owners,
'input': tx_input,
'fulfillment': None,
'fid': fid
})
# create
else:
fulfillments.append({
'current_owners': current_owners,
'input': None,
'fulfillment': None,
'fid': 0
})
# handle outputs
conditions = []
for fulfillment in fulfillments:
# threshold condition
if len(new_owners) > 1:
condition = cc.ThresholdSha256Fulfillment(
threshold=len(new_owners))
for new_owner in new_owners:
condition.add_subfulfillment(
cc.Ed25519Fulfillment(public_key=new_owner))
# simple signature condition
elif len(new_owners) == 1:
condition = cc.Ed25519Fulfillment(public_key=new_owners[0])
# to be added later (hashlock conditions)
else:
condition = None
if condition:
conditions.append({
'new_owners': new_owners,
'condition': {
'details': condition.to_dict(),
'uri': condition.condition_uri
},
'cid': fulfillment['fid']
})
tx = {
'fulfillments': fulfillments,
'conditions': conditions,
'operation': operation,
'timestamp': timestamp(),
'data': data
}
# serialize and convert to bytes
tx_hash = get_hash_data(tx)
# create the transaction
transaction = {'id': tx_hash, 'version': 1, 'transaction': tx}
return transaction
def escrow_asset(bigchain,
source,
to,
asset_id,
sk,
expires_at=None,
ilp_header=None,
execution_condition=None):
asset = bigchain.get_transaction(asset_id['txid'])
payload = asset['transaction']['data']['payload'].copy()
if ilp_header:
payload.update({'ilp_header': ilp_header})
# Create escrow template with the execute and abort address
asset_escrow = bigchain.create_transaction(source, [source, to],
asset_id,
'TRANSFER',
payload=payload)
if not expires_at:
# Set expiry time (100 secs from now)
time_sleep = 100
expires_at = float(bigchaindb.util.timestamp()) + time_sleep
# Create escrow and timeout condition
condition_escrow = cc.ThresholdSha256Fulfillment(threshold=1) # OR Gate
condition_timeout = cc.TimeoutFulfillment(
expire_time=str(expires_at)) # only valid if now() <= time_expire
condition_timeout_inverted = cc.InvertedThresholdSha256Fulfillment(
threshold=1)
condition_timeout_inverted.add_subfulfillment(condition_timeout)
# Create execute branch
execution_threshold = 3 if execution_condition else 2
condition_execute = cc.ThresholdSha256Fulfillment(
threshold=execution_threshold) # AND gate
condition_execute.add_subfulfillment(
cc.Ed25519Fulfillment(public_key=to)) # execute address
condition_execute.add_subfulfillment(
condition_timeout) # federation checks on expiry
if execution_condition:
condition_execute.add_subcondition_uri(execution_condition)
condition_escrow.add_subfulfillment(condition_execute)
# Create abort branch
condition_abort = cc.ThresholdSha256Fulfillment(threshold=2) # AND gate
condition_abort.add_subfulfillment(
cc.Ed25519Fulfillment(public_key=source)) # abort address
condition_abort.add_subfulfillment(condition_timeout_inverted)
condition_escrow.add_subfulfillment(condition_abort)
# Update the condition in the newly created transaction
asset_escrow['transaction']['conditions'][0]['condition'] = {
'details': condition_escrow.to_dict(),
'uri': condition_escrow.condition.serialize_uri()
}
# conditions have been updated, so hash needs updating
asset_escrow['id'] = bigchaindb.util.get_hash_data(asset_escrow)
# sign transaction
asset_escrow_signed = bigchaindb.util.sign_tx(asset_escrow,
sk,
bigchain=bigchain)
bigchain.write_transaction(asset_escrow_signed)
return asset_escrow_signed
import cryptoconditions as cc
SPACER = '*' * 40
# Create some keys and a message to sign
sk1, vk1 = cc.crypto.ed25519_generate_key_pair()
sk2, vk2 = cc.crypto.ed25519_generate_key_pair()
message = 'Hello World! I am a message to sign!'
##############################################################
# Create a Threshold fulfillment and
# add subfulfillments and subconditions as an object or by URI
##############################################################
# Create a 1-of-4 threshold condition (OR gate)
threshold_fulfillment = cc.ThresholdSha256Fulfillment(threshold=1)
# Add a hashlock fulfillment
threshold_fulfillment.add_subfulfillment(
cc.PreimageSha256Fulfillment(b'much secret'))
# Add a signature condition
threshold_fulfillment.add_subcondition(
cc.Ed25519Fulfillment(public_key=vk1).condition)
# Add a fulfillment URI
threshold_fulfillment.add_subfulfillment_uri('cf:0:')
# Add a condition URI
threshold_fulfillment.add_subcondition_uri(
'cc:0:3:47DEQpj8HBSa-_TImW-5JCeuQeRkm5NMpJWZG3hSuFU:0')
print(SPACER)
print('Condition URI: {}'.format(threshold_fulfillment.condition_uri))
print('Threshold: {}'.format(threshold_fulfillment.threshold))
print('Is valid fulfillment? {}'.format(
# signature_treshold = 2
# Create some new testusers
thresholduser1_priv, thresholduser1_pub = crypto.generate_key_pair()
thresholduser2_priv, thresholduser2_pub = crypto.generate_key_pair()
# Retrieve the last transaction of testuser2
tx_retrieved_id = b.get_owned_ids(testuser2_pub).pop()
# Create a base template for a 1-input/2-output transaction
threshold_tx = b.create_transaction(testuser2_pub,
[thresholduser1_pub, thresholduser2_pub],
tx_retrieved_id, 'TRANSFER')
# Create a Threshold Cryptocondition
threshold_condition = cc.ThresholdSha256Fulfillment(
threshold=signature_treshold)
threshold_condition.add_subfulfillment(
cc.Ed25519Fulfillment(public_key=thresholduser1_pub))
threshold_condition.add_subfulfillment(
cc.Ed25519Fulfillment(public_key=thresholduser2_pub))
# Update the condition in the newly created transaction
threshold_tx['transaction']['conditions'][0]['condition'] = {
'details': json.loads(threshold_condition.serialize_json()),
'uri': threshold_condition.condition.serialize_uri()
}
# Conditions have been updated, so the transaction hash (ID) needs updating
threshold_tx['id'] = util.get_hash_data(threshold_tx)
# Sign the transaction