seal

seal is a Rust crate that wraps the Microsoft SEAL library to enable us to perform arithimetic operations over encrypted data. It is a fork of the Sunscreen's SEAL bindings that you can found here.

Architecture

All types in this crate implement Sync/Send. So long as you never dereference the internal handle on any type after it has been dropped, these traits should safely hold. The internal handles should be of little use to you anyways.

Schemes implemented:

• Brakerski/Fan-Vercauteren (BFV)
• Cheon-Kim-Kim-Song (CKKS)

lib.rs:

Example

use sealy::{
    BFVEncoder, BFVEvaluator, BfvEncryptionParametersBuilder, CoefficientModulus, Context,
    Decryptor, DegreeType, Encoder, Encryptor, Evaluator, KeyGenerator, PlainModulus,
    SecurityLevel,
};

fn main() -> anyhow::Result<()> {
    let params = BfvEncryptionParametersBuilder::new()
        .set_poly_modulus_degree(DegreeType::D8192)
        .set_coefficient_modulus(
            CoefficientModulus::create(DegreeType::D8192, &[50, 30, 30, 50, 50]).unwrap(),
        )
        .set_plain_modulus(PlainModulus::batching(DegreeType::D8192, 32)?)
        .build()?;

    let ctx = Context::new(&params, false, SecurityLevel::TC128)?;
    let gen = KeyGenerator::new(&ctx)?;

    let encoder = BFVEncoder::new(&ctx)?;

    let public_key = gen.create_public_key();
    let secret_key = gen.secret_key();

    let encryptor = Encryptor::with_public_key(&ctx, &public_key)?;
    let decryptor = Decryptor::new(&ctx, &secret_key)?;
    let evaluator = BFVEvaluator::new(&ctx)?;

    let plaintext: Vec<i64> = vec![1, 2, 3];
    let factor = vec![2, 2, 2];

    let encoded_plaintext = encoder.encode(&plaintext)?;
    let encoded_factor = encoder.encode(&factor)?;

    let ciphertext = encryptor.encrypt(&encoded_plaintext)?;
    let ciphertext_result = evaluator.multiply_plain(&ciphertext, &encoded_factor)?;

    let decrypted = decryptor.decrypt(&ciphertext_result)?;
    let decoded = encoder.decode(&decrypted);

    println!("{:?}", &decoded.into_iter().take(3).collect::<Vec<_>>()); // [2, 4, 6]

    Ok(())
}