TNO Quantum

TNO Quantum provides generic software components aimed at facilitating the development of quantum applications.

TNO Quantum - Communication - QKD Key Rate

This repository provides python code to compute optimal protocol parameters for different quantum key distribution (QKD) protocols.

The codebase is based on the following TNO papers:

• Attema et al. - Optimizing the decoy-state BB84 QKD protocol parameters (2021) (doi: 10.1007/s11128-021-03078-0)

• Ma et al. - Quantum key distribution with entangled photon sources (2007) (doi: 10.1103/PhysRevA.76.012307)

The following quantum protocols are being supported:

• BB84 protocol (bb84),

• BB84 protocol using a single photon source (bb84_single_photon),

• BBM92 protocol (bbm92).

The following classical error-correction protocols are being supported:

• Cascade (cascade),

• Winnow (winnow).

The presented code can be used to

• determine optimal parameter settings needed to obtain the maximum key rate,

• correct errors in exchanged sifted keys for the different QKD protocols,

• apply privacy amplification by calculating secure key using hash function.

Quick Install

The QKD Key Rate module can easily be installed using pip as follows:

pip install tno.quantum.communication.qkd_key_rate

Examples

The following code demonstrates how the bb84 protocol can be used to calculate optimal key-rate for a specific detector with attenuation=0.2.

from tno.quantum.communication.qkd_key_rate.protocols.quantum.bb84 import (
   BB84FullyAsymptoticKeyRateEstimate,
)
from tno.quantum.communication.qkd_key_rate.test.conftest import standard_detector

detector_Bob = standard_detector.customise(
   dark_count_rate=1e-8,
   polarization_drift=0,
   error_detector=0.1,
   efficiency_party=1,
)

fully_asymptotic_key_rate = BB84FullyAsymptoticKeyRateEstimate(detector=detector_Bob)
mu, rate = fully_asymptotic_key_rate.optimize_rate(attenuation=0.2)

The following example demonstrates usage of the winnow error correction protocol.

import numpy as np

from tno.quantum.communication.qkd_key_rate.base import Message, Permutations, Schedule
from tno.quantum.communication.qkd_key_rate.protocols.classical.winnow import (
   WinnowCorrector,
   WinnowReceiver,
   WinnowSender,
)

error_rate = 0.05
message_length = 10000
input_message = Message.random_message(message_length=message_length)
error_message = Message(
   [x if np.random.rand() > error_rate else 1 - x for x in input_message]
)
schedule = Schedule.schedule_from_error_rate(error_rate=error_rate)
number_of_passes = np.sum(schedule.schedule)
permutations = Permutations.random_permutation(
   number_of_passes=number_of_passes, message_size=message_length
)

alice = WinnowSender(
   message=input_message, permutations=permutations, schedule=schedule
)
bob = WinnowReceiver(
   message=error_message, permutations=permutations, schedule=schedule
)
corrector = WinnowCorrector(alice=alice, bob=bob)
summary = corrector.correct_errors()

For more usage examples see the the documentation of the individual modules

• qkd_key_rate.protocols.quantum.bb84

• qkd_key_rate.protocols.quantum.bb84_single_photon

• qkd_key_rate.protocols.quantum.bbm92

• qkd_key_rate.protocols.classical.cascade

• qkd_key_rate.protocols.classical.winnow

• qkd_key_rate.protocols.classical.privacy_amplification

(End)use Limitations

The content of this software may solely be used for applications that comply with international export control laws.