poulpy-core 0.5.0

A backend agnostic crate implementing RLWE-based encryption & arithmetic.
Documentation 
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use poulpy_hal::{
    api::{ModuleN, ScratchAvailable, VecZnxAutomorphismInplace, VecZnxAutomorphismInplaceTmpBytes},
    layouts::{Backend, DataMut, Module, Scratch, ZnxView, ZnxViewMut},
    source::Source,
};

use crate::{
    ScratchTakeCore,
    encryption::glwe_switching_key::GLWESwitchingKeyEncryptSk,
    layouts::{
        GGLWEInfos, GGLWEToMut, GLWESecret, GLWESwitchingKey, GLWESwitchingKeyDegreesMut, LWEInfos, LWESecret, LWESecretToRef,
        LWESwitchingKey, Rank, prepared::GLWESecretPreparedFactory,
    },
};

impl LWESwitchingKey<Vec<u8>> {
    pub fn encrypt_sk_tmp_bytes<M, A, BE: Backend>(module: &M, infos: &A) -> usize
    where
        A: GGLWEInfos,
        M: LWESwitchingKeyEncrypt<BE>,
    {
        module.lwe_switching_key_encrypt_sk_tmp_bytes(infos)
    }
}

impl<D: DataMut> LWESwitchingKey<D> {
    pub fn encrypt_sk<S1, S2, M, BE: Backend>(
        &mut self,
        module: &M,
        sk_lwe_in: &S1,
        sk_lwe_out: &S2,
        source_xa: &mut Source,
        source_xe: &mut Source,
        scratch: &mut Scratch<BE>,
    ) where
        S1: LWESecretToRef,
        S2: LWESecretToRef,
        M: LWESwitchingKeyEncrypt<BE>,
    {
        module.lwe_switching_key_encrypt_sk(self, sk_lwe_in, sk_lwe_out, source_xa, source_xe, scratch);
    }
}

pub trait LWESwitchingKeyEncrypt<BE: Backend> {
    fn lwe_switching_key_encrypt_sk_tmp_bytes<A>(&self, infos: &A) -> usize
    where
        A: GGLWEInfos;

    fn lwe_switching_key_encrypt_sk<R, S1, S2>(
        &self,
        res: &mut R,
        sk_lwe_in: &S1,
        sk_lwe_out: &S2,
        source_xa: &mut Source,
        source_xe: &mut Source,
        scratch: &mut Scratch<BE>,
    ) where
        R: GGLWEToMut + GLWESwitchingKeyDegreesMut + GGLWEInfos,
        S1: LWESecretToRef,
        S2: LWESecretToRef;
}

impl<BE: Backend> LWESwitchingKeyEncrypt<BE> for Module<BE>
where
    Self: ModuleN
        + GLWESwitchingKeyEncryptSk<BE>
        + GLWESecretPreparedFactory<BE>
        + VecZnxAutomorphismInplace<BE>
        + VecZnxAutomorphismInplaceTmpBytes,
    Scratch<BE>: ScratchTakeCore<BE>,
{
    fn lwe_switching_key_encrypt_sk_tmp_bytes<A>(&self, infos: &A) -> usize
    where
        A: GGLWEInfos,
    {
        assert_eq!(infos.dsize().0, 1, "dsize > 1 is not supported for LWESwitchingKey");
        assert_eq!(infos.rank_in().0, 1, "rank_in > 1 is not supported for LWESwitchingKey");
        assert_eq!(infos.rank_out().0, 1, "rank_out > 1 is not supported for LWESwitchingKey");
        assert_eq!(self.n() as u32, infos.n());

        let lvl_0: usize = GLWESecret::bytes_of(self.n().into(), Rank(1));
        let lvl_1: usize = GLWESecret::bytes_of(self.n().into(), Rank(1));
        let lvl_2: usize = self
            .vec_znx_automorphism_inplace_tmp_bytes()
            .max(GLWESwitchingKey::encrypt_sk_tmp_bytes(self, infos));

        lvl_0 + lvl_1 + lvl_2
    }

    #[allow(clippy::too_many_arguments)]
    fn lwe_switching_key_encrypt_sk<R, S1, S2>(
        &self,
        res: &mut R,
        sk_lwe_in: &S1,
        sk_lwe_out: &S2,
        source_xa: &mut Source,
        source_xe: &mut Source,
        scratch: &mut Scratch<BE>,
    ) where
        R: GGLWEToMut + GLWESwitchingKeyDegreesMut + GGLWEInfos,
        S1: LWESecretToRef,
        S2: LWESecretToRef,
    {
        let sk_lwe_in: &LWESecret<&[u8]> = &sk_lwe_in.to_ref();
        let sk_lwe_out: &LWESecret<&[u8]> = &sk_lwe_out.to_ref();

        assert!(sk_lwe_in.n().0 <= res.n().0);
        assert!(sk_lwe_out.n().0 <= res.n().0);
        assert!(res.n() <= self.n() as u32);
        assert!(
            scratch.available() >= self.lwe_switching_key_encrypt_sk_tmp_bytes(res),
            "scratch.available(): {} < LWESwitchingKeyEncrypt::lwe_switching_key_encrypt_sk_tmp_bytes: {}",
            scratch.available(),
            self.lwe_switching_key_encrypt_sk_tmp_bytes(res)
        );

        let (mut sk_glwe_in, scratch_1) = scratch.take_glwe_secret(self.n().into(), Rank(1));
        let (mut sk_glwe_out, scratch_2) = scratch_1.take_glwe_secret(self.n().into(), Rank(1));

        sk_glwe_in.dist = sk_lwe_in.dist;
        sk_glwe_out.dist = sk_lwe_out.dist;

        sk_glwe_out.data.at_mut(0, 0)[..sk_lwe_out.n().into()].copy_from_slice(sk_lwe_out.data.at(0, 0));
        sk_glwe_out.data.at_mut(0, 0)[sk_lwe_out.n().into()..].fill(0);
        self.vec_znx_automorphism_inplace(-1, &mut sk_glwe_out.data.as_vec_znx_mut(), 0, scratch_2);

        sk_glwe_in.data.at_mut(0, 0)[..sk_lwe_in.n().into()].copy_from_slice(sk_lwe_in.data.at(0, 0));
        sk_glwe_in.data.at_mut(0, 0)[sk_lwe_in.n().into()..].fill(0);
        self.vec_znx_automorphism_inplace(-1, &mut sk_glwe_in.data.as_vec_znx_mut(), 0, scratch_2);

        self.glwe_switching_key_encrypt_sk(res, &sk_glwe_in, &sk_glwe_out, source_xa, source_xe, scratch_2);
    }
}