sl-paillier

sl-paillier provides a Paillier cryptosystem implementation built on crypto-bigint.

The crate currently targets Rust 1.88 and ships a 2048-bit configuration as its main public API.

Main types

SK2048: secret key
PK2048: public key
RawPlaintext
RawCiphertext

Features

serde: enables serialization support for the 2048-bit key and ciphertext types, and exposes MinimalSK2048 / MinimalPK2048 for compact key serialization

Supported operations

key generation with SK2048::gen() / SK2048::gen_keys()
plaintext construction with PK2048::message() and PK2048::into_message()
encryption with PK2048::encrypt() or PK2048::encrypt_with_r()
decryption with SK2048::decrypt() and CRT-accelerated SK2048::decrypt_fast()
additive homomorphism with PK2048::add()
multiplication by a plaintext scalar with PK2048::mul()

PK2048::mul_vartime() is also exposed as an explicitly variable-time variant.

Example

use rand::thread_rng;
use sl_paillier::SK2048;

let mut rng = thread_rng();
let (sk, pk) = SK2048::gen_keys(&mut rng);

let m1 = pk.message(&[5]).unwrap();
let m2 = pk.message(&[9]).unwrap();

let c1 = pk.encrypt(&m1, &mut rng);
let c2 = pk.encrypt(&m2, &mut rng);

let sum = pk.add(&c1, &c2);
let doubled = pk.mul(&c1, &pk.message(&[2]).unwrap());

assert_eq!(sk.decrypt(&sum), pk.message(&[14]).unwrap());
assert_eq!(sk.decrypt_fast(&sum), pk.message(&[14]).unwrap());
assert_eq!(sk.decrypt_fast(&doubled), pk.message(&[10]).unwrap());

Notes