1use poulpy_hal::{
  2    api::{
  3        ScratchAvailable, SvpApplyDftToDftInplace, SvpPPolAllocBytes, SvpPrepare, TakeScalarZnx, TakeVecZnx, TakeVecZnxDft,
  4        VecZnxAddInplace, VecZnxAddNormal, VecZnxAddScalarInplace, VecZnxBigNormalize, VecZnxDftAllocBytes, VecZnxDftApply,
  5        VecZnxFillUniform, VecZnxIdftApplyConsume, VecZnxNormalize, VecZnxNormalizeInplace, VecZnxNormalizeTmpBytes, VecZnxSub,
  6        VecZnxSubInplace, VecZnxSwitchRing,
  7    },
  8    layouts::{Backend, DataMut, DataRef, Module, ScalarZnx, Scratch},
  9    source::Source,
 10};
 11
 12use crate::{
 13    TakeGLWESecretPrepared,
 14    layouts::{
 15        Degree, GGLWECiphertext, GGLWELayoutInfos, GGLWESwitchingKey, GLWEInfos, GLWESecret, LWEInfos,
 16        prepared::GLWESecretPrepared,
 17    },
 18};
 19
 20impl GGLWESwitchingKey<Vec<u8>> {
 21    pub fn encrypt_sk_scratch_space<B: Backend, A>(module: &Module<B>, infos: &A) -> usize
 22    where
 23        A: GGLWELayoutInfos,
 24        Module<B>: SvpPPolAllocBytes + VecZnxNormalizeTmpBytes + VecZnxDftAllocBytes + VecZnxNormalizeTmpBytes,
 25    {
 26        (GGLWECiphertext::encrypt_sk_scratch_space(module, infos) | ScalarZnx::alloc_bytes(module.n(), 1))
 27            + ScalarZnx::alloc_bytes(module.n(), infos.rank_in().into())
 28            + GLWESecretPrepared::alloc_bytes(module, &infos.glwe_layout())
 29    }
 30
 31    pub fn encrypt_pk_scratch_space<B: Backend, A>(module: &Module<B>, _infos: &A) -> usize
 32    where
 33        A: GGLWELayoutInfos,
 34    {
 35        GGLWECiphertext::encrypt_pk_scratch_space(module, _infos)
 36    }
 37}
 38
 39impl<DataSelf: DataMut> GGLWESwitchingKey<DataSelf> {
 40    #[allow(clippy::too_many_arguments)]
 41    pub fn encrypt_sk<DataSkIn: DataRef, DataSkOut: DataRef, B: Backend>(
 42        &mut self,
 43        module: &Module<B>,
 44        sk_in: &GLWESecret<DataSkIn>,
 45        sk_out: &GLWESecret<DataSkOut>,
 46        source_xa: &mut Source,
 47        source_xe: &mut Source,
 48        scratch: &mut Scratch<B>,
 49    ) where
 50        Module<B>: VecZnxAddScalarInplace
 51            + VecZnxDftAllocBytes
 52            + VecZnxBigNormalize<B>
 53            + VecZnxDftApply<B>
 54            + SvpApplyDftToDftInplace<B>
 55            + VecZnxIdftApplyConsume<B>
 56            + VecZnxNormalizeTmpBytes
 57            + VecZnxFillUniform
 58            + VecZnxSubInplace
 59            + VecZnxAddInplace
 60            + VecZnxNormalizeInplace<B>
 61            + VecZnxAddNormal
 62            + VecZnxNormalize<B>
 63            + VecZnxSub
 64            + SvpPrepare<B>
 65            + VecZnxSwitchRing
 66            + SvpPPolAllocBytes,
 67        Scratch<B>: TakeVecZnxDft<B> + ScratchAvailable + TakeVecZnx + TakeScalarZnx + TakeGLWESecretPrepared<B>,
 68    {
 69        #[cfg(debug_assertions)]
 70        {
 71            assert!(sk_in.n().0 <= module.n() as u32);
 72            assert!(sk_out.n().0 <= module.n() as u32);
 73            assert!(
 74                scratch.available() >= GGLWESwitchingKey::encrypt_sk_scratch_space(module, self),
 75                "scratch.available()={} < GLWESwitchingKey::encrypt_sk_scratch_space={}",
 76                scratch.available(),
 77                GGLWESwitchingKey::encrypt_sk_scratch_space(module, self)
 78            )
 79        }
 80
 81        let n: usize = sk_in.n().max(sk_out.n()).into();
 82
 83        let (mut sk_in_tmp, scratch_1) = scratch.take_scalar_znx(n, sk_in.rank().into());
 84        (0..sk_in.rank().into()).for_each(|i| {
 85            module.vec_znx_switch_ring(
 86                &mut sk_in_tmp.as_vec_znx_mut(),
 87                i,
 88                &sk_in.data.as_vec_znx(),
 89                i,
 90            );
 91        });
 92
 93        let (mut sk_out_tmp, scratch_2) = scratch_1.take_glwe_secret_prepared(Degree(n as u32), sk_out.rank());
 94        {
 95            let (mut tmp, _) = scratch_2.take_scalar_znx(n, 1);
 96            (0..sk_out.rank().into()).for_each(|i| {
 97                module.vec_znx_switch_ring(&mut tmp.as_vec_znx_mut(), 0, &sk_out.data.as_vec_znx(), i);
 98                module.svp_prepare(&mut sk_out_tmp.data, i, &tmp, 0);
 99            });
100        }
101
102        self.key.encrypt_sk(
103            module,
104            &sk_in_tmp,
105            &sk_out_tmp,
106            source_xa,
107            source_xe,
108            scratch_2,
109        );
110        self.sk_in_n = sk_in.n().into();
111        self.sk_out_n = sk_out.n().into();
112    }
113}