poulpy-core 0.6.0

A backend-agnostic crate implementing Module-LWE-based encryption and arithmetic
Documentation
use std::collections::HashMap;

use itertools::Itertools;
use poulpy_hal::{
    api::{ScratchOwnedAlloc, ScratchOwnedBorrow},
    layouts::{Module, ScratchOwned},
    source::Source,
    test_suite::TestParams,
};

use crate::{
    EncryptionLayout, GLWEAutomorphismKeyEncryptSk, GLWEDecrypt, GLWEEncryptSk, GLWENoise, GLWEPacking, GLWERotate, GLWESub,
    ScratchArenaTakeCore,
    layouts::{
        GLWE, GLWEAutomorphismKey, GLWEAutomorphismKeyLayout, GLWEAutomorphismKeyPreparedFactory, GLWELayout, GLWEPlaintext,
        GLWESecret, GLWESecretPreparedFactory, LWEInfos, ModuleCoreAlloc,
        prepared::{GLWEAutomorphismKeyPrepared, GLWESecretPrepared},
    },
};

pub fn test_glwe_packing<BE: crate::test_suite::TestBackend>(params: &TestParams, module: &Module<BE>)
where
    BE::OwnedBuf: poulpy_hal::layouts::HostDataMut,
    for<'a> BE::BufRef<'a>: poulpy_hal::layouts::HostDataRef,
    for<'a> BE::BufMut<'a>: poulpy_hal::layouts::HostDataMut,
    Module<BE>: GLWEEncryptSk<BE>
        + GLWEAutomorphismKeyEncryptSk<BE>
        + GLWEAutomorphismKeyPreparedFactory<BE>
        + GLWEPacking<BE>
        + GLWESecretPreparedFactory<BE>
        + GLWESub<BE>
        + GLWEDecrypt<BE>
        + GLWERotate<BE>
        + GLWENoise<BE>,
    ScratchOwned<BE>: ScratchOwnedAlloc<BE> + ScratchOwnedBorrow<BE>,
    for<'a> poulpy_hal::layouts::ScratchArena<'a, BE>: ScratchArenaTakeCore<'a, BE>,
{
    let mut source_xs: Source = Source::new([0u8; 32]);
    let mut source_xe: Source = Source::new([0u8; 32]);
    let mut source_xa: Source = Source::new([0u8; 32]);

    let n: usize = module.n();
    let base2k: usize = params.base2k;
    let out_base2k: usize = base2k - 1;
    let key_base2k: usize = base2k;
    let k_ct: usize = 4 * base2k + 1;
    let pt_k: usize = 2 * base2k + 1;
    let rank: usize = 3;
    let dsize: usize = 1;
    let k_ksk: usize = k_ct + key_base2k * dsize;

    let dnum: usize = k_ct.div_ceil(key_base2k * dsize);

    let glwe_out_infos = EncryptionLayout::new_from_default_sigma(GLWELayout {
        n: n.into(),
        base2k: out_base2k.into(),
        k: k_ct.into(),
        rank: rank.into(),
    })
    .unwrap();

    let key_infos = EncryptionLayout::new_from_default_sigma(GLWEAutomorphismKeyLayout {
        n: n.into(),
        base2k: key_base2k.into(),
        k: k_ksk.into(),
        rank: rank.into(),
        dsize: dsize.into(),
        dnum: dnum.into(),
    })
    .unwrap();

    let mut scratch: ScratchOwned<BE> = ScratchOwned::alloc(
        (module)
            .glwe_encrypt_sk_tmp_bytes(&glwe_out_infos)
            .max((module).glwe_automorphism_key_encrypt_sk_tmp_bytes(&key_infos))
            .max(module.glwe_pack_tmp_bytes(&glwe_out_infos, &key_infos)),
    );

    let mut sk: GLWESecret<Vec<u8>> = module.glwe_secret_alloc_from_infos(&glwe_out_infos);
    sk.fill_ternary_prob(0.5, &mut source_xs);

    let mut sk_prep: GLWESecretPrepared<BE::OwnedBuf, BE> = module.glwe_secret_prepared_alloc_from_infos(&sk);
    module.glwe_secret_prepare(&mut sk_prep, &sk);

    let mut pt: GLWEPlaintext<Vec<u8>> = module.glwe_plaintext_alloc_from_infos(&glwe_out_infos);
    let mut data: Vec<i64> = vec![0i64; n];
    data.iter_mut().enumerate().for_each(|(i, x)| {
        *x = i as i64;
    });

    pt.encode_vec_i64(&data, pt_k.into());

    let gal_els: Vec<i64> = module.glwe_pack_galois_elements();

    let mut auto_keys: HashMap<i64, GLWEAutomorphismKeyPrepared<BE::OwnedBuf, BE>> = HashMap::new();
    let mut tmp: GLWEAutomorphismKey<Vec<u8>> = module.glwe_automorphism_key_alloc_from_infos(&key_infos);
    gal_els.iter().for_each(|gal_el| {
        module.glwe_automorphism_key_encrypt_sk(
            &mut tmp,
            *gal_el,
            &sk,
            &key_infos,
            &mut source_xe,
            &mut source_xa,
            &mut crate::test_suite::scratch_host_arena(&mut scratch),
        );
        let mut atk_prepared: GLWEAutomorphismKeyPrepared<BE::OwnedBuf, BE> =
            module.glwe_automorphism_key_prepared_alloc_from_infos(&tmp);
        module.glwe_automorphism_key_prepare(&mut atk_prepared, &tmp, &mut scratch.borrow());
        auto_keys.insert(*gal_el, atk_prepared);
    });

    let mut cts = (0..n)
        .step_by(5)
        .map(|_| {
            let mut ct = module.glwe_alloc_from_infos(&glwe_out_infos);
            module.glwe_encrypt_sk(
                &mut ct,
                &pt,
                &sk_prep,
                &glwe_out_infos,
                &mut source_xe,
                &mut source_xa,
                &mut scratch.borrow(),
            );
            module.glwe_rotate_assign(-5, &mut pt, &mut scratch.borrow());
            ct
        })
        .collect_vec();

    let mut cts_map: HashMap<usize, &mut GLWE<Vec<u8>>> = HashMap::new();

    for (i, ct) in cts.iter_mut().enumerate() {
        cts_map.insert(5 * i, ct);
    }

    let mut res: GLWE<Vec<u8>> = module.glwe_alloc_from_infos(&glwe_out_infos);

    module.glwe_pack(&mut res, cts_map, 0, &auto_keys, key_infos.size(), &mut scratch.borrow());

    let mut pt_want: GLWEPlaintext<Vec<u8>> = module.glwe_plaintext_alloc_from_infos(&glwe_out_infos);
    let mut data: Vec<i64> = vec![0i64; n];
    data.iter_mut().enumerate().for_each(|(i, x)| {
        if i.is_multiple_of(5) {
            *x = i as i64;
        }
    });

    pt_want.encode_vec_i64(&data, pt_k.into());

    assert!(
        module
            .glwe_noise(&res, &pt_want, &sk_prep, &mut scratch.borrow())
            .std()
            .log2()
            <= ((k_ct - out_base2k) as f64)
    );
}