def q_bit(host, encode):
q = Qubit(host)
if encode == '+':
q.H()
if encode == '-':
q.X()
q.H()
if encode == '0':
q.I()
if encode == '1':
q.X()
return q
def protocol_alice(alice, bob, secret_key, sample_len):
for bit in secret_key:
q_bit = Qubit(alice)
if bit == 1:
q_bit.H()
alice.send_qubit(bob, q_bit, await_ack=True)
mes = alice.get_next_classical(bob)
if mes is not None:
test = mes.content
secret_key = element_by_indexes(secret_key, test, 1)
mes = alice.get_next_classical(bob)
if mes is not None:
sample_bob = mes.content
if sample_bob == secret_key[:sample_len]:
alice.send_classical(bob, "NO INTERCEPT", await_ack=True)
print("alice key ", secret_key)
else:
alice.send_classical(bob, "EVE IS LISTENING", await_ack=True)
print("STACCAH STACCAH")
def entangle(host): # 01 - 10
q1 = Qubit(host)
q2 = Qubit(host)
q1.X()
q1.H()
q2.X()
q1.cnot(q2)
return q1, q2
def alice(alice, bob, number_of_entanglement_pairs):
angles = [0, np.pi / 4, np.pi / 2]
bases_choice = [
random.randint(1, 3) for i in range(number_of_entanglement_pairs)
]
test_results_alice = []
test_bases_alice = []
sifted_key_alice = []
for i in range(number_of_entanglement_pairs):
qubit_a = Qubit(alice)
qubit_b = Qubit(alice)
# preparation of singlet state (1/sqrt(2))*(|01> - |10>)
qubit_a.X()
qubit_b.X()
qubit_a.H()
qubit_a.cnot(qubit_b)
print('Sending EPR pair %d' % (i + 1))
_, ack_arrived = alice.send_qubit(bob, qubit_b, await_ack=True)
if ack_arrived:
#rotate qubit and measure
base_a = bases_choice[i]
qubit_a.rz(angles[base_a - 1])
meas_a = qubit_a.measure()
ack_arrived = alice.send_classical(bob, base_a, await_ack=True)
if not ack_arrived:
print("Send data failed!")
message = alice.get_next_classical(bob, wait=2)
if message is not None:
base_b = message.content
if (base_a == 2 and base_b == 1) or (base_a == 3
and base_b == 2):
sifted_key_alice.append(meas_a)
elif (base_a == 1
and base_b == 1) or (base_a == 1 and base_b == 3) or (
base_a == 3 and base_b == 1) or (base_a == 3
and base_b == 3):
test_bases_alice.append('a' + str(base_a))
test_results_alice.append(str(meas_a))
else:
print("The message did not arrive")
else:
print('The EPR pair was not properly established')
ack_arrived = alice.send_classical(bob,
(test_results_alice, test_bases_alice),
await_ack=True)
if not ack_arrived:
print("Send data failed!")
print("Sifted_key_alice: ", sifted_key_alice)
def encode(self, host_sender, bitstring, bases):
encoded_qubits = []
for i in range(len(bitstring)):
q = Qubit(host_sender)
if bases[i] == "0":
if bitstring[i] == "0":
pass # initialized in 0
elif bitstring[i] == "1":
q.X()
elif bases[i] == "1":
if bitstring[i] == "0":
q.H()
elif bitstring[i] == "1":
q.X()
q.H()
encoded_qubits.append(q)
# Stop the network at the end of the example
# network.stop(stop_hosts=True)
return encoded_qubits
def preparation_and_distribution():
for serial in range(NO_OF_SERIALS):
for bit_no in range(QUBITS_PER_MONEY):
random_bit = randint(0, 1)
random_base = randint(0, 1)
bank_bits[serial].append(random_bit)
bank_basis[serial].append(random_base)
q = Qubit(host)
if random_bit == 1:
q.X()
if random_base == 1:
q.H()
host.send_qubit(customer, q, True)
def sender_qkd(alice, secret_key, receiver):
sent_qubit_counter = 0
for bit in secret_key:
success = False
while success == False:
qubit = Qubit(alice)
if bit == 1:
qubit.H()
# If we want to send 0, we'll send |0>
# If we want to send 1, we'll send |+>
alice.send_qubit(receiver, qubit, await_ack=True)
message = alice.get_next_classical(receiver, wait=-1)
if message is not None:
if message.content == 'qubit successfully acquired':
print(f'Alice sent qubit {sent_qubit_counter+1} to Bob')
success = True
sent_qubit_counter += 1
def _send_key(packet):
receiver = network.get_host(packet.receiver)
sender = network.get_host(packet.sender)
key_size = packet.payload[Constants.KEYSIZE]
packet.protocol = Constants.KEY
network.send(packet)
secret_key = np.random.randint(2, size=key_size)
msg_buff = []
sender.qkd_keys[receiver.host_id] = secret_key.tolist()
sequence_nr = 0
# iterate over all bits in the secret key.
for bit in secret_key:
ack = False
while not ack:
# get a random base. 0 for Z base and 1 for X base.
base = random.randint(0, 1)
# create qubit
q_bit = Qubit(sender)
# Set qubit to the bit from the secret key.
if bit == 1:
q_bit.X()
# Apply basis change to the bit if necessary.
if base == 1:
q_bit.H()
# Send Qubit to Receiver
sender.send_qubit(receiver.host_id, q_bit, await_ack=True)
# Get measured basis of Receiver
message = sender.get_next_classical_message(receiver.host_id, msg_buff, sequence_nr)
# Compare to send basis, if same, answer with 0 and set ack True and go to next bit,
# otherwise, send 1 and repeat.
if message == "%d:%d" % (sequence_nr, base):
ack = True
sender.send_classical(receiver.host_id, ("%d:0" % sequence_nr), await_ack=True)
else:
ack = False
sender.send_classical(receiver.host_id, ("%d:1" % sequence_nr), await_ack=True)
sequence_nr += 1
def _establish_epr(self, sender, receiver, q_id, o_seq_num, blocked):
"""
Instead doing an entanglement swap, for efficiency we establish EPR pairs
directly for simulation, if an entanglement swap would have been possible.
Args:
sender (Host): Sender of the EPR pair
receiver (Host): Receiver of the EPR pair
q_id (str): Qubit ID of the sent EPR pair
o_seq_num (int): The original sequence number
blocked (bool): If the pair being distributed is blocked or not
"""
host_sender = self.get_host(sender)
host_receiver = self.get_host(receiver)
q1 = Qubit(host_sender)
q2 = Qubit(host_sender)
q1.H()
q1.cnot(q2)
host_sender.add_epr(receiver, q1, q_id, blocked)
host_receiver.add_epr(sender, q2, q_id, blocked)
host_receiver.send_ack(sender, o_seq_num)
def alice_qkd(alice, msg_buff, secret_key, receiver):
sequence_nr = 0
# iterate over all bits in the secret key.
for bit in secret_key:
ack = False
while not ack:
print("Alice sent %d key bits" % (sequence_nr + 1))
# get a random base. 0 for Z base and 1 for X base.
base = random.randint(0, 1)
# create qubit
q_bit = Qubit(alice)
# Set qubit to the bit from the secret key.
if bit == 1:
q_bit.X()
# Apply basis change to the bit if necessary.
if base == 1:
q_bit.H()
# Send Qubit to Bob
alice.send_qubit(receiver, q_bit, await_ack=True)
# Get measured basis of Bob
message = alice.get_next_classical_message(receiver, msg_buff,
sequence_nr)
# Compare to send basis, if same, answer with 0 and set ack True and go to next bit,
# otherwise, send 1 and repeat.
if message == ("%d:%d") % (sequence_nr, base):
ack = True
alice.send_classical(receiver, ("%d:0" % sequence_nr),
await_ack=True)
else:
ack = False
alice.send_classical(receiver, ("%d:1" % sequence_nr),
await_ack=True)
sequence_nr += 1
def test_single_gates(self):
for b in TestBackend.backends:
backend = b()
network = Network.get_instance()
network.start(["Alice", "Bob"], backend)
alice = Host('Alice', backend)
bob = Host('Bob', backend)
alice.start()
bob.start()
network.add_host(alice)
network.add_host(bob)
q = Qubit(alice)
q.X()
self.assertEqual(1, q.measure())
q = Qubit(alice)
q.H()
q.H()
self.assertEqual(0, q.measure())
network.stop(True)
def _send_key(packet):
def helper_recv(host, receive_from_id, buffer, sequence_nr):
buffer.append(host.get_next_classical(receive_from_id, wait=-1))
msg = "ACK"
while msg == "ACK" or (msg.split(':')[0] != ("%d" % sequence_nr)):
if len(buffer) == 0:
buffer.append(host.get_next_classical(receive_from_id,
wait=-1))
ele = buffer.pop(0)
msg = ele.content
return msg
receiver = network.get_host(packet.receiver)
sender = network.get_host(packet.sender)
key_size = packet.payload[Constants.KEYSIZE]
packet.protocol = Constants.REC_KEY
network.send(packet)
secret_key = []
msg_buff = []
sequence_nr = 0
attempt_counter = 0
# iterate over all bits in the secret key.
for _ in range(key_size):
ack = False
while not ack:
# get a random base. 0 for Z base and 1 for X base.
base = random.randint(0, 1)
bit = random.randint(0, 1)
# create qubit
q_bit = Qubit(sender)
# Set qubit to the bit from the secret key.
if bit == 1:
q_bit.X()
# Apply basis change to the bit if necessary.
if base == 1:
q_bit.H()
# Send Qubit to Receiver
sender.send_qubit(receiver.host_id, q_bit, await_ack=True)
# Get measured basis of Receiver
message = helper_recv(sender, receiver.host_id, msg_buff,
sequence_nr)
# Compare to send basis, if same, answer with 0 and set ack True and go to next bit,
# otherwise, send 1 and repeat.
if message == "%d:%d" % (sequence_nr, base):
ack = True
# Bit got accepted, add to key
secret_key.append(bit)
sender.send_classical(receiver.host_id, ("%d:0" % sequence_nr),
await_ack=True)
else:
ack = False
sender.send_classical(receiver.host_id, ("%d:1" % sequence_nr),
await_ack=True)
sequence_nr += 1
attempt_counter += 1
# Add key to keys of sender
sender.qkd_keys[receiver.host_id] = (secret_key, attempt_counter)
def handshake_receiver(host, sender_id):
"""
Establishes a classical TCP-like handshake with the sender .
If successful starts to receive the qubits , otherwise terminated the connection.
:param host: Receiver host
:param sender_id: ID of the sender
:return: If successful returns True, otherwise False
"""
latest_seq_num = host.get_sequence_number_receiver(sender_id)
# Receive the EPR half of Alice and the SYN message
qb_2 = host.get_data_qubit(sender_id, wait=WAIT_TIME)
if qb_2 is None:
print('qb_2 is None')
return False
message_recv = host.get_classical(sender_id, (latest_seq_num + 1), wait=WAIT_TIME)
if not message_recv:
print('No message has arrived')
return False
message_recv = message_recv.content
if message_recv == '10':
print("SYN is received by Bob")
else:
return False
# Create an EPR pair.
qb_3 = Qubit(host)
qb_4 = Qubit(host)
qb_3.H()
qb_3.cnot(qb_4)
# Send half of the EPR pair created (qubit 3) and send back the qubit 2 that Alice has sent first.
_, ack_received = host.send_qubit(sender_id, qb_2, await_ack=True)
if ack_received is False:
print('ACK is not received')
return False
_, ack_received = host.send_qubit(sender_id, qb_3, await_ack=True)
if ack_received is False:
print('ACK is not received')
return False
# Send SYN-ACK message.
host.send_classical(sender_id, SYN_ACK, True)
latest_seq_num = host.get_sequence_number_receiver(sender_id)
# Receive the ACK message.
message = host.get_classical(sender_id, latest_seq_num, wait=WAIT_TIME)
if message is None:
print('ACK was not received by Bob')
return False
if message.content == '01':
print('ACK was received by Bob')
# Receive the qubit 3.
qa_3 = host.get_data_qubit(sender_id, wait=WAIT_TIME)
if qa_3 is None:
return False
# Make a Bell State measurement in qubit 3 and qubit 4.
qa_3.cnot(qb_4)
qa_3.H()
qa_3_check = qa_3.measure()
qb_4_check = qb_4.measure()
# If measurement results are as expected , establish the TCP connection.
# Else report that there is something wrong.
if qa_3_check == 0 and qb_4_check == 0:
print("TCP connection established.")
return True
else:
print("Something is wrong.")
return False
def handshake_sender(host, receiver_id):
"""
Establishes a classical TCP-like handshake with the receiver .
If successful starts the transmission of qubits , otherwise terminated the connection.
:param host: Sender of qubits
:param receiver_id: ID of the receiver
:return: If successful returns True, otherwise False
"""
# Create an EPR pair.
qa_1 = Qubit(host)
qa_2 = Qubit(host)
qa_1.H()
qa_1.cnot(qa_2)
# Send a half of EPR pair and the SYN message to Bob.
_, ack_received = host.send_qubit(receiver_id, qa_2, await_ack=True)
if ack_received is False:
print('ACK is not received')
return False
ack_received = host.send_classical(receiver_id, SYN, await_ack=True)
if ack_received is False:
print('ACK is not received')
return False
syn_seq_num = host.get_sequence_number_receiver(receiver_id)
# Receive the qubits Bob has sent (qubit 2 and qubit 3) for SYN-ACK.
qb_2 = host.get_data_qubit(receiver_id, wait=WAIT_TIME)
if qb_2 is None:
return False
qb_3 = host.get_data_qubit(receiver_id, wait=WAIT_TIME)
if qb_3 is None:
return False
# Receive the classical message Bob has sent for SYN-ACK.
message_recv = host.get_classical(receiver_id, syn_seq_num + 2, wait=WAIT_TIME)
if message_recv is None:
return False
if message_recv.content == '11':
print("SYN-ACK is received by Alice")
else:
print('Connection terminated - 1 ')
return False
# Make a Bell State measurement on qubit 1 and qubit 2.
qa_1.cnot(qb_2)
qa_1.H()
qa_1_check = qa_1.measure()
qb_2_check = qb_2.measure()
# If measurement results are as expected, send Bob a ACK message and the qubit 3 that he has sent previously.
# Else report that there is something wrong.
if qa_1_check == 0 and qb_2_check == 0:
ack_received = host.send_classical(receiver_id, ACK, await_ack=True)
if ack_received is False:
print('ACK is not received')
return False
_, ack_received = host.send_qubit(receiver_id, qb_3, await_ack=True)
if ack_received is False:
print('ACK is not received')
return False
return True
else:
print("Something is wrong.")
return False
