1use backend::hal::{
  2    api::{
  3        ScratchAvailable, SvpApplyInplace, SvpPPolAllocBytes, SvpPrepare, TakeScalarZnx, TakeVecZnx, TakeVecZnxDft,
  4        VecZnxAddInplace, VecZnxAddNormal, VecZnxAddScalarInplace, VecZnxBigNormalize, VecZnxDftAllocBytes, VecZnxDftFromVecZnx,
  5        VecZnxDftToVecZnxBigConsume, VecZnxFillUniform, VecZnxNormalize, VecZnxNormalizeInplace, VecZnxNormalizeTmpBytes,
  6        VecZnxSub, VecZnxSubABInplace, VecZnxSwithcDegree,
  7    },
  8    layouts::{Backend, DataMut, DataRef, Module, ScalarZnx, Scratch},
  9};
 10use sampling::source::Source;
 11
 12use crate::{
 13    TakeGLWESecretPrepared,
 14    layouts::{GGLWECiphertext, GLWESecret, compressed::GGLWESwitchingKeyCompressed, prepared::GLWESecretPrepared},
 15};
 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>: VecZnxNormalizeTmpBytes + VecZnxDftAllocBytes + VecZnxNormalizeTmpBytes + SvpPPolAllocBytes,
 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>: SvpPrepare<B>
 47            + SvpPPolAllocBytes
 48            + VecZnxSwithcDegree
 49            + VecZnxDftAllocBytes
 50            + VecZnxBigNormalize<B>
 51            + VecZnxDftFromVecZnx<B>
 52            + SvpApplyInplace<B>
 53            + VecZnxDftToVecZnxBigConsume<B>
 54            + VecZnxNormalizeTmpBytes
 55            + VecZnxFillUniform
 56            + VecZnxSubABInplace
 57            + VecZnxAddInplace
 58            + VecZnxNormalizeInplace<B>
 59            + VecZnxAddNormal
 60            + VecZnxNormalize<B>
 61            + VecZnxSub
 62            + VecZnxAddScalarInplace,
 63        Scratch<B>: TakeVecZnxDft<B> + ScratchAvailable + TakeVecZnx + TakeScalarZnx + TakeGLWESecretPrepared<B>,
 64    {
 65        #[cfg(debug_assertions)]
 66        {
 67            use crate::layouts::{GGLWESwitchingKey, Infos};
 68
 69            assert!(sk_in.n() <= module.n());
 70            assert!(sk_out.n() <= module.n());
 71            assert!(
 72                scratch.available()
 73                    >= GGLWESwitchingKey::encrypt_sk_scratch_space(
 74                        module,
 75                        sk_out.n(),
 76                        self.basek(),
 77                        self.k(),
 78                        self.rank_in(),
 79                        self.rank_out()
 80                    ),
 81                "scratch.available()={} < GLWESwitchingKey::encrypt_sk_scratch_space={}",
 82                scratch.available(),
 83                GGLWESwitchingKey::encrypt_sk_scratch_space(
 84                    module,
 85                    sk_out.n(),
 86                    self.basek(),
 87                    self.k(),
 88                    self.rank_in(),
 89                    self.rank_out()
 90                )
 91            )
 92        }
 93
 94        let n: usize = sk_in.n().max(sk_out.n());
 95
 96        let (mut sk_in_tmp, scratch1) = scratch.take_scalar_znx(n, sk_in.rank());
 97        (0..sk_in.rank()).for_each(|i| {
 98            module.vec_znx_switch_degree(
 99                &mut sk_in_tmp.as_vec_znx_mut(),
100                i,
101                &sk_in.data.as_vec_znx(),
102                i,
103            );
104        });
105
106        let (mut sk_out_tmp, scratch2) = scratch1.take_glwe_secret_prepared(n, sk_out.rank());
107        {
108            let (mut tmp, _) = scratch2.take_scalar_znx(n, 1);
109            (0..sk_out.rank()).for_each(|i| {
110                module.vec_znx_switch_degree(&mut tmp.as_vec_znx_mut(), 0, &sk_out.data.as_vec_znx(), i);
111                module.svp_prepare(&mut sk_out_tmp.data, i, &tmp, 0);
112            });
113        }
114
115        self.key.encrypt_sk(
116            module,
117            &sk_in_tmp,
118            &sk_out_tmp,
119            seed_xa,
120            source_xe,
121            sigma,
122            scratch2,
123        );
124        self.sk_in_n = sk_in.n();
125        self.sk_out_n = sk_out.n();
126    }
127}