1use poulpy_hal::{
  2    api::{ScratchOwnedAlloc, ScratchOwnedBorrow, ZnAddNormal, ZnFillUniform, ZnNormalizeInplace},
  3    layouts::{Backend, DataMut, Module, ScratchOwned, Zn, ZnxView, ZnxViewMut},
  4    oep::{ScratchOwnedAllocImpl, ScratchOwnedBorrowImpl},
  5    source::Source,
  6};
  7
  8use crate::{
  9    encryption::{SIGMA, SIGMA_BOUND},
 10    layouts::{LWE, LWEInfos, LWEPlaintext, LWEPlaintextToRef, LWESecret, LWESecretToRef, LWEToMut},
 11};
 12
 13impl<DataSelf: DataMut> LWE<DataSelf> {
 14    pub fn encrypt_sk<P, S, M, BE: Backend>(&mut self, module: &M, pt: &P, sk: &S, source_xa: &mut Source, source_xe: &mut Source)
 15    where
 16        P: LWEPlaintextToRef,
 17        S: LWESecretToRef,
 18        M: LWEEncryptSk<BE>,
 19        BE: Backend + ScratchOwnedAllocImpl<BE> + ScratchOwnedBorrowImpl<BE>,
 20    {
 21        module.lwe_encrypt_sk(self, pt, sk, source_xa, source_xe);
 22    }
 23}
 24
 25pub trait LWEEncryptSk<BE: Backend> {
 26    fn lwe_encrypt_sk<R, P, S>(&self, res: &mut R, pt: &P, sk: &S, source_xa: &mut Source, source_xe: &mut Source)
 27    where
 28        R: LWEToMut,
 29        P: LWEPlaintextToRef,
 30        S: LWESecretToRef;
 31}
 32
 33impl<BE: Backend> LWEEncryptSk<BE> for Module<BE>
 34where
 35    Self: Sized + ZnFillUniform + ZnAddNormal + ZnNormalizeInplace<BE>,
 36    BE: ScratchOwnedAllocImpl<BE> + ScratchOwnedBorrowImpl<BE>,
 37{
 38    fn lwe_encrypt_sk<R, P, S>(&self, res: &mut R, pt: &P, sk: &S, source_xa: &mut Source, source_xe: &mut Source)
 39    where
 40        R: LWEToMut,
 41        P: LWEPlaintextToRef,
 42        S: LWESecretToRef,
 43    {
 44        let res: &mut LWE<&mut [u8]> = &mut res.to_mut();
 45        let pt: &LWEPlaintext<&[u8]> = &pt.to_ref();
 46        let sk: &LWESecret<&[u8]> = &sk.to_ref();
 47
 48        #[cfg(debug_assertions)]
 49        {
 50            assert_eq!(res.n(), sk.n())
 51        }
 52
 53        let base2k: usize = res.base2k().into();
 54        let k: usize = res.k().into();
 55
 56        self.zn_fill_uniform((res.n() + 1).into(), base2k, &mut res.data, 0, source_xa);
 57
 58        let mut tmp_znx: Zn<Vec<u8>> = Zn::alloc(1, 1, res.size());
 59
 60        let min_size = res.size().min(pt.size());
 61
 62        (0..min_size).for_each(|i| {
 63            tmp_znx.at_mut(0, i)[0] = pt.data.at(0, i)[0]
 64                - res.data.at(0, i)[1..]
 65                    .iter()
 66                    .zip(sk.data.at(0, 0))
 67                    .map(|(x, y)| x * y)
 68                    .sum::<i64>();
 69        });
 70
 71        (min_size..res.size()).for_each(|i| {
 72            tmp_znx.at_mut(0, i)[0] -= res.data.at(0, i)[1..]
 73                .iter()
 74                .zip(sk.data.at(0, 0))
 75                .map(|(x, y)| x * y)
 76                .sum::<i64>();
 77        });
 78
 79        self.zn_add_normal(
 80            1,
 81            base2k,
 82            &mut res.data,
 83            0,
 84            k,
 85            source_xe,
 86            SIGMA,
 87            SIGMA_BOUND,
 88        );
 89
 90        self.zn_normalize_inplace(
 91            1,
 92            base2k,
 93            &mut tmp_znx,
 94            0,
 95            ScratchOwned::alloc(size_of::<i64>()).borrow(),
 96        );
 97
 98        (0..res.size()).for_each(|i| {
 99            res.data.at_mut(0, i)[0] = tmp_znx.at(0, i)[0];
100        });
101    }
102}