Add Eve and readme

README.md

@@ -0,0 +1,13 @@
+# Квантовая криптография - менторский проект
+
+
+## Симулятор
+
+Симулятор лежит в папке `model`. Его главные элементы:
+
+- Абстрактный класс `Channel` ([тут](model/channel.py)). В нем описаны методы, которые должны быть у канала. 
+Теоретически можно написать реализацию даже для реального оборудования, но тут есть только `ChannelSym` - симуляция канала.
+
+- Класс `Alice` ([тут](model/alice.py)). Объекты этого класса используют канал (то есть объект любого класса, реализующего абстрактные методы из `Channel`) и реализуют протокол генерации ключа BB84 со стороны отправителя.
+- Класс `Bob` ([тут](model/bob.py)). Как Алиса, только не Алиса, а Боб: реализует получателя в протоколе
+- Класс `EveBS` ([тут](model/eve.py)). Реализует beam splitter атаку на `ChannelSym`

model/alice.py

@@ -1,5 +1,5 @@
 from dataclasses import dataclass, field
-from channel import Channel, QChannelImpl
+from channel import Channel, ChannelSym
 import random as r
 import typing
 from utils import bin_encode, bin_decode

model/bob.py

@@ -1,9 +1,9 @@
 from dataclasses import dataclass, field
-from channel import Channel, QChannelImpl
+from channel import Channel, ChannelSym
 import random as r
 import typing
 
-from model.utils import bin_encode, bin_decode
+from utils import bin_encode, bin_decode
 
 
 @dataclass

model/channel.py

@@ -27,7 +27,7 @@ class Channel(abc.ABC):
 
 
 @dataclass
-class QChannelImpl(Channel):
+class ChannelSym(Channel):
     # [[(value, basis)]]
     bob_photons: typing.List[typing.List[typing.Tuple[bool, bool]]] = field(default_factory=list)
     bob_classical_data_pool: str = ''
@@ -41,12 +41,12 @@ class QChannelImpl(Channel):
     # eta - the probability for a detector to react to a photon
     detector_sensitivity: float = 0.8
     transmittance: float = 0.8
+    eve: typing.Optional[typing.Any] = None
 
     def get_number_of_photos(self) -> int:
         return round(np.random.poisson(self.mu))
 
     def send_classical(self, data: str, is_bob: bool = True):
-        # print(f'{["Alice", "Bob"][is_bob]} is sending data: {data}')
         if is_bob:
             self.bob_classical_data_pool += data
         else:
@@ -55,14 +55,14 @@ class QChannelImpl(Channel):
     def send_bit(self, bit: bool, basis: bool):
         n_photons = self.get_number_of_photos()
         delta = [(bit, basis) for _i in range(n_photons)]
+        if self.eve is not None:
+            delta = self.eve.process_photons(delta)
         self.bob_photons.append(delta)
 
     def recv_classical(self, n: int, is_bob: bool = True) -> str:
         pool_name = ['alice_classical_data_pool', 'bob_classical_data_pool'][not is_bob]
         if n == -1:
             n = len(getattr(self, pool_name))
-        # print(f'{["Alice", "Bob"][is_bob]} is receiving {n} '
-        #       f'characters of data. Length now: {len(getattr(self, pool_name))}')
         while len(getattr(self, pool_name)) < n:
             pass
         data = getattr(self, pool_name)[:n]
@@ -72,6 +72,8 @@ class QChannelImpl(Channel):
 
     def get_photon_results(self, basises: typing.Optional[typing.List[bool]]) -> typing.List[typing.Tuple[bool, bool]]:
         res = list()
+        while len(self.bob_photons) < len(basises):
+            pass
         for photons, basis in zip(self.bob_photons, basises):
             clicks = [random.uniform(0, 1) <= self.p_dc, random.uniform(0, 1) <= self.p_dc]
             for ph_bit, ph_basis in photons:

model/eve.py

@@ -0,0 +1,30 @@
+from dataclasses import dataclass, field
+import typing
+from random import choice, uniform
+
+
+@dataclass
+class EveBS:
+    hijack_probability: float = 0.45
+    my_basises: typing.List[bool] = field(default_factory=list)
+    obtained_data: typing.List[typing.Optional[bool]] = field(default_factory=list)
+
+    def process_photons(self, photons: typing.List[typing.Tuple[bool, bool]]) -> typing.List[typing.Tuple[bool, bool]]:
+        basis = choice([False, True])
+        self.my_basises.append(basis)
+        clicks = [0, 0]
+        passed = []
+        for photon in photons:
+            if uniform(0, 1) <= self.hijack_probability:
+                photon_bit, photon_basis = photon
+                if photon_basis == basis:
+                    clicks[photon_bit] += 1
+                else:
+                    clicks[choice([0, 1])] += 1
+            else:
+                passed.append(photon)
+        if any(clicks) and not all(clicks):
+            self.obtained_data.append(bool(clicks[1]))
+        else:
+            self.obtained_data.append(None)
+        return passed

model/main.py

@@ -1,11 +1,13 @@
 from alice import Alice
 from bob import Bob
-from channel import QChannelImpl
+from channel import ChannelSym
 from threading import Thread
 import typing
 
+from eve import EveBS
 
-def run_qkd(alice, bob, n=1000):
+
+def run_qkd(alice: Alice, bob: Bob, n: int = 1000):
     alice_thread = Thread(target=lambda: alice.generate_key(n))
     bob_thread = Thread(target=lambda: bob.generate_key(n))
     alice_thread.start()
@@ -18,25 +20,58 @@ def get_e_and_r(alice, bob, n=1000) -> typing.Tuple[float, float]:
     return 1 - sum(k1 == k2 for k1, k2 in zip(alice.key, bob.key)) / len(alice.key), len(alice.key) / n
 
 
-if __name__ == '__main__':
+channel_parameters = {'p_opt': 0.05, 'p_dc': 0.05, 'mu': 1, 'detector_sensitivity': 0.8, 'transmittance': 0.8}
+
+
+def plot(parameter, values, add_eve: bool = True):
+    data_r, data_e = [], []
+    n = 1000
+    for val in values:
+        print(val)
+        channel = ChannelSym(**{parameter: val})
+        alice, bob = Alice(channel), Bob(channel)
+        if add_eve:
+            eve = EveBS()
+            channel.eve = eve
+        run_qkd(alice, bob, n)
+        e, r = get_e_and_r(alice, bob, n)
+        data_r.append(r)
+        data_e.append(e)
+    from matplotlib import pyplot as plt
+    plt.plot(values, data_r)
+    plt.plot(values, data_e)
+    plt.legend(['R', 'E'])
+    plt.xlabel({'p_dc': '$p_{dc}$'}.get(parameter, parameter))
+    plt.title('$R$ and $E$ vs. ' + {'p_dc': '$p_{dc}$'}.get(parameter, parameter) + ' with Eve' * add_eve)
+    plt.show()
+
+
+def run_one():
     N = 1000
-    channel = QChannelImpl()
+    channel = ChannelSym()
     alice, bob = Alice(channel), Bob(channel)
     run_qkd(alice, bob)
     # print(list(map(int, alice.key)))
     # print(list(map(int, bob.key)))
-    # print('Alice bits:   ', *list(map(int, alice.sent)))
-    # print('Bob bits:     ',
-    #       *list(map(lambda t: {(0, 1): 1, (1, 0): 0, (0, 0): 2, (1, 1): 3}[(int(t[0]), int(t[1]))], bob.my_results)))
-    # print('Alice basises:', *list(map(int, alice.my_basises)))
-    # print('Bob basises:  ', *list(map(int, bob.my_basises)))
-    # bob_correctness = [left + right == 1 for left, right in bob.my_results]
-    # print('              ', *[
-    #     int(k) if c and b1 == b2 else ' '
-    #     for c, k, b1, b2 in zip(bob_correctness, alice.sent, bob.my_basises, alice.my_basises)])
-    # print('              ', *[
-    #     {(0, 1): 1, (1, 0): 0, (0, 0): 2, (1, 1): 3}[(int(k[0]), int(k[1]))] if c and b1 == b2 else ' '
-    #     for c, k, b1, b2 in zip(bob_correctness, bob.my_results, bob.my_basises, alice.my_basises)])
-    # print(f'{100 * sum(k1 == k2 for k1, k2 in zip(alice.key, bob.key)) / len(alice.key):.2f}%, key length: {len(alice.key)}')
+    print('Alice bits:   ', *list(map(int, alice.sent)))
+    print('Bob bits:     ',
+          *list(map(lambda t: {(0, 1): 1, (1, 0): 0, (0, 0): 2, (1, 1): 3}[(int(t[0]), int(t[1]))], bob.my_results)))
+    print('Alice basises:', *list(map(int, alice.my_basises)))
+    print('Bob basises:  ', *list(map(int, bob.my_basises)))
+    bob_correctness = [left + right == 1 for left, right in bob.my_results]
+    print('              ', *[
+        int(k) if c and b1 == b2 else ' '
+        for c, k, b1, b2 in zip(bob_correctness, alice.sent, bob.my_basises, alice.my_basises)])
+    print('              ', *[
+        {(0, 1): 1, (1, 0): 0, (0, 0): 2, (1, 1): 3}[(int(k[0]), int(k[1]))] if c and b1 == b2 else ' '
+        for c, k, b1, b2 in zip(bob_correctness, bob.my_results, bob.my_basises, alice.my_basises)])
+    print(
+        f'{100 * sum(k1 == k2 for k1, k2 in zip(alice.key, bob.key)) / len(alice.key):.2f}%, '
+        f'key length: {len(alice.key)}')
     e, r = get_e_and_r(alice, bob, N)
     print(f'E: {e * 100:.1f}%, R: {r}')
+
+
+if __name__ == '__main__':
+    import numpy as np
+    plot('p_dc', np.arange(0, 0.1, 0.01))