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