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, ZnxZero},
    source::Source,
};

use crate::{
    GGLWEEncryptSk, ScratchTakeCore,
    layouts::{
        GGLWE, GGLWEInfos, GGLWEToMut, GLWESecret, GLWESecretToRef, GLWEToLWEKey, LWEInfos, LWESecret, LWESecretToRef, Rank,
        prepared::{GLWESecretPrepared, GLWESecretPreparedFactory},
    },
};

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

impl<D: DataMut> GLWEToLWEKey<D> {
    pub fn encrypt_sk<M, S1, S2, BE: Backend>(
        &mut self,
        module: &M,
        sk_lwe: &S1,
        sk_glwe: &S2,
        source_xa: &mut Source,
        source_xe: &mut Source,
        scratch: &mut Scratch<BE>,
    ) where
        M: GLWEToLWESwitchingKeyEncryptSk<BE>,
        S1: LWESecretToRef,
        S2: GLWESecretToRef,
        Scratch<BE>: ScratchTakeCore<BE>,
    {
        module.glwe_to_lwe_key_encrypt_sk(self, sk_lwe, sk_glwe, source_xa, source_xe, scratch);
    }
}

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

    fn glwe_to_lwe_key_encrypt_sk<R, S1, S2>(
        &self,
        res: &mut R,
        sk_lwe: &S1,
        sk_glwe: &S2,
        source_xa: &mut Source,
        source_xe: &mut Source,
        scratch: &mut Scratch<BE>,
    ) where
        S1: LWESecretToRef,
        S2: GLWESecretToRef,
        R: GGLWEToMut + GGLWEInfos;
}

impl<BE: Backend> GLWEToLWESwitchingKeyEncryptSk<BE> for Module<BE>
where
    Self: ModuleN
        + GGLWEEncryptSk<BE>
        + GLWESecretPreparedFactory<BE>
        + VecZnxAutomorphismInplace<BE>
        + VecZnxAutomorphismInplaceTmpBytes,
    Scratch<BE>: ScratchTakeCore<BE>,
{
    fn glwe_to_lwe_key_encrypt_sk_tmp_bytes<A>(&self, infos: &A) -> usize
    where
        A: GGLWEInfos,
    {
        assert_eq!(self.n() as u32, infos.n());

        let lvl_0: usize = GLWESecretPrepared::bytes_of(self, infos.rank_in());
        let lvl_1_sk_lwe_as_glwe: usize =
            GLWESecret::bytes_of(self.n().into(), infos.rank_in()) + self.vec_znx_automorphism_inplace_tmp_bytes();
        let lvl_1_encrypt: usize = GGLWE::encrypt_sk_tmp_bytes(self, infos);

        lvl_0 + lvl_1_sk_lwe_as_glwe.max(lvl_1_encrypt)
    }

    fn glwe_to_lwe_key_encrypt_sk<R, S1, S2>(
        &self,
        res: &mut R,
        sk_lwe: &S1,
        sk_glwe: &S2,
        source_xa: &mut Source,
        source_xe: &mut Source,
        scratch: &mut Scratch<BE>,
    ) where
        S1: LWESecretToRef,
        S2: GLWESecretToRef,
        R: GGLWEToMut + GGLWEInfos,
    {
        let sk_lwe: &LWESecret<&[u8]> = &sk_lwe.to_ref();
        let sk_glwe: &GLWESecret<&[u8]> = &sk_glwe.to_ref();

        assert!(sk_lwe.n().0 <= self.n() as u32);
        assert!(
            scratch.available() >= self.glwe_to_lwe_key_encrypt_sk_tmp_bytes(res),
            "scratch.available(): {} < GLWEToLWESwitchingKeyEncryptSk::glwe_to_lwe_key_encrypt_sk_tmp_bytes: {}",
            scratch.available(),
            self.glwe_to_lwe_key_encrypt_sk_tmp_bytes(res)
        );

        let (mut sk_lwe_as_glwe_prep, scratch_1) = scratch.take_glwe_secret_prepared(self, Rank(1));

        {
            let (mut sk_lwe_as_glwe, scratch_2) = scratch_1.take_glwe_secret(self.n().into(), sk_lwe_as_glwe_prep.rank());
            sk_lwe_as_glwe.dist = sk_lwe.dist;
            sk_lwe_as_glwe.data.zero();
            sk_lwe_as_glwe.data.at_mut(0, 0)[..sk_lwe.n().into()].copy_from_slice(sk_lwe.data.at(0, 0));
            self.vec_znx_automorphism_inplace(-1, &mut sk_lwe_as_glwe.data.as_vec_znx_mut(), 0, scratch_2);
            sk_lwe_as_glwe_prep.prepare(self, &sk_lwe_as_glwe);
        }

        self.gglwe_encrypt_sk(res, &sk_glwe.data, &sk_lwe_as_glwe_prep, source_xa, source_xe, scratch_1);
    }
}