private_key_noiseless.py

import random
from utils import *


class NoiselessPrivateKey:
    def __init__(self, n, q):
        self.n = n
        self.q = q

    def key_gen(self):
        self.s = sample_uniform_vector(self.n, self.q)

    def encrypt(self, m):
        A = sample_uniform_matrix(self.n, self.q)
        b = matrix_vector_multiplication(A, self.s, self.q)
        b = vector_vector_addition(b, m, self.q)
        return (A, b)

    def decrypt(self, ctx):
        (A, b) = ctx[0], ctx[1]
        As = matrix_vector_multiplication(A, self.s, self.q)

        for i in range(self.n):
            b[i] = (b[i] - As[i]) % self.q

        return b


if __name__ == "__main__":
    import time

    q = 3000
    n = 1000

    E = NoiselessPrivateKey(n, q)

    t = time.time()
    E.key_gen()
    t_keys = time.time()
    print(f"Generating keys took {t_keys-t} seconds...")

    m = [random.randint(0, 1) for _ in range(n)]
    print("Encrypting random message...")

    t = time.time()
    c = E.encrypt(m)
    t_enc = time.time()
    print(f"Encrypting took {t_enc-t} seconds...")

    t = time.time()
    m_prime = E.decrypt(c)
    t_dec = time.time()
    print(f"Decrypting took {t_dec-t} seconds...")

    assert m == m_prime

    print("Decrypting was successful!")