rens-paillier 1.2.1

Paillier encryption

Paillier encryption

python3.8 package for Paillier encryption.

Example usage

Setup

from paillier.keygen import generate_keys
from paillier.crypto import encrypt, decrypt

pk, sk = generate_keys()

Basic encryption and decryption

m1 = 45336
ciphertext = encrypt(pk, m1)
assert m1 == decrypt(pk, sk, ciphertext)

Homomorphic things

from paillier.crypto import secure_addition, scalar_multiplication, secure_subtraction

n, _ = pk
m2 = 30381

# Secure addition
e1 = encrypt(pk, m1)
e2 = encrypt(pk, m2)
addition = secure_addition(e1, e2, n)
assert m1 + m2 == decrypt(pk, sk, addition)

# Scalar multiplication
k = 23  # some scalar
e1 = encrypt(pk, m1)
multiplied = scalar_multiplication(e1, k, n)
assert (m1 * k) % n == decrypt(pk, sk, multiplied)

# Secure subtraction
assert m1 > m2, "m2 should be bigger than m1 in order to subtract m2 from m1"
e1 = encrypt(pk, m1)
e2 = encrypt(pk, m2)
subtracted = secure_subtraction(e1, e2, n)
assert m1 - m2 == decrypt(pk, sk, subtracted)