1use backend::hal::{
  2    api::{ScratchAvailable, TakeScalarZnx, TakeVecZnx, TakeVecZnxDft, VecZnxAddScalarInplace, VecZnxSwithcDegree},
  3    layouts::{Backend, DataMut, DataRef, Module, ScalarZnx, Scratch},
  4};
  5use sampling::source::Source;
  6
  7use crate::{
  8    TakeGLWESecretPrepared,
  9    layouts::{
 10        GGLWECiphertext, GGLWESwitchingKey, GLWESecret, Infos, compressed::GGLWESwitchingKeyCompressed,
 11        prepared::GLWESecretPrepared,
 12    },
 13};
 14
 15use crate::trait_families::{GGLWESwitchingKeyEncryptSkFamily, GLWESecretPreparedModuleFamily};
 16
 17impl GGLWESwitchingKeyCompressed<Vec<u8>> {
 18    pub fn encrypt_sk_scratch_space<B: Backend>(
 19        module: &Module<B>,
 20        n: usize,
 21        basek: usize,
 22        k: usize,
 23        rank_in: usize,
 24        rank_out: usize,
 25    ) -> usize
 26    where
 27        Module<B>: GGLWESwitchingKeyEncryptSkFamily<B> + GLWESecretPreparedModuleFamily<B>,
 28    {
 29        (GGLWECiphertext::encrypt_sk_scratch_space(module, n, basek, k) | ScalarZnx::alloc_bytes(n, 1))
 30            + ScalarZnx::alloc_bytes(n, rank_in)
 31            + GLWESecretPrepared::bytes_of(module, n, rank_out)
 32    }
 33}
 34
 35impl<DataSelf: DataMut> GGLWESwitchingKeyCompressed<DataSelf> {
 36    pub fn encrypt_sk<DataSkIn: DataRef, DataSkOut: DataRef, B: Backend>(
 37        &mut self,
 38        module: &Module<B>,
 39        sk_in: &GLWESecret<DataSkIn>,
 40        sk_out: &GLWESecret<DataSkOut>,
 41        seed_xa: [u8; 32],
 42        source_xe: &mut Source,
 43        sigma: f64,
 44        scratch: &mut Scratch<B>,
 45    ) where
 46        Module<B>:
 47            GGLWESwitchingKeyEncryptSkFamily<B> + VecZnxSwithcDegree + VecZnxAddScalarInplace + GLWESecretPreparedModuleFamily<B>,
 48        Scratch<B>:
 49            ScratchAvailable + TakeScalarZnx + TakeVecZnxDft<B> + TakeGLWESecretPrepared<B> + ScratchAvailable + TakeVecZnx,
 50    {
 51        #[cfg(debug_assertions)]
 52        {
 53            assert!(sk_in.n() <= module.n());
 54            assert!(sk_out.n() <= module.n());
 55            assert!(
 56                scratch.available()
 57                    >= GGLWESwitchingKey::encrypt_sk_scratch_space(
 58                        module,
 59                        sk_out.n(),
 60                        self.basek(),
 61                        self.k(),
 62                        self.rank_in(),
 63                        self.rank_out()
 64                    ),
 65                "scratch.available()={} < GLWESwitchingKey::encrypt_sk_scratch_space={}",
 66                scratch.available(),
 67                GGLWESwitchingKey::encrypt_sk_scratch_space(
 68                    module,
 69                    sk_out.n(),
 70                    self.basek(),
 71                    self.k(),
 72                    self.rank_in(),
 73                    self.rank_out()
 74                )
 75            )
 76        }
 77
 78        let n: usize = sk_in.n().max(sk_out.n());
 79
 80        let (mut sk_in_tmp, scratch1) = scratch.take_scalar_znx(n, sk_in.rank());
 81        (0..sk_in.rank()).for_each(|i| {
 82            module.vec_znx_switch_degree(
 83                &mut sk_in_tmp.as_vec_znx_mut(),
 84                i,
 85                &sk_in.data.as_vec_znx(),
 86                i,
 87            );
 88        });
 89
 90        let (mut sk_out_tmp, scratch2) = scratch1.take_glwe_secret_prepared(n, sk_out.rank());
 91        {
 92            let (mut tmp, _) = scratch2.take_scalar_znx(n, 1);
 93            (0..sk_out.rank()).for_each(|i| {
 94                module.vec_znx_switch_degree(&mut tmp.as_vec_znx_mut(), 0, &sk_out.data.as_vec_znx(), i);
 95                module.svp_prepare(&mut sk_out_tmp.data, i, &tmp, 0);
 96            });
 97        }
 98
 99        self.key.encrypt_sk(
100            module,
101            &sk_in_tmp,
102            &sk_out_tmp,
103            seed_xa,
104            source_xe,
105            sigma,
106            scratch2,
107        );
108        self.sk_in_n = sk_in.n();
109        self.sk_out_n = sk_out.n();
110    }
111}