1use backend::hal::{
  2    api::{
  3        ScratchAvailable, SvpApplyInplace, TakeVecZnx, TakeVecZnxDft, VecZnxAddInplace, VecZnxAddNormal, VecZnxAddScalarInplace,
  4        VecZnxBigNormalize, VecZnxDftAllocBytes, VecZnxDftFromVecZnx, VecZnxDftToVecZnxBigConsume, VecZnxFillUniform,
  5        VecZnxNormalize, VecZnxNormalizeInplace, VecZnxNormalizeTmpBytes, VecZnxSub, VecZnxSubABInplace, ZnxZero,
  6    },
  7    layouts::{Backend, DataMut, DataRef, Module, ScalarZnx, Scratch},
  8};
  9use sampling::source::Source;
 10
 11use crate::{
 12    TakeGLWEPt,
 13    layouts::{GGLWECiphertext, GLWECiphertext, GLWEPlaintext, Infos, prepared::GLWESecretPrepared},
 14};
 15
 16impl GGLWECiphertext<Vec<u8>> {
 17    pub fn encrypt_sk_scratch_space<B: Backend>(module: &Module<B>, n: usize, basek: usize, k: usize) -> usize
 18    where
 19        Module<B>: VecZnxNormalizeTmpBytes + VecZnxDftAllocBytes + VecZnxNormalizeTmpBytes,
 20    {
 21        GLWECiphertext::encrypt_sk_scratch_space(module, n, basek, k)
 22            + (GLWEPlaintext::byte_of(n, basek, k) | module.vec_znx_normalize_tmp_bytes(n))
 23    }
 24
 25    pub fn encrypt_pk_scratch_space<B: Backend>(_module: &Module<B>, _n: usize, _basek: usize, _k: usize, _rank: usize) -> usize {
 26        unimplemented!()
 27    }
 28}
 29
 30impl<DataSelf: DataMut> GGLWECiphertext<DataSelf> {
 31    #[allow(clippy::too_many_arguments)]
 32    pub fn encrypt_sk<DataPt: DataRef, DataSk: DataRef, B: Backend>(
 33        &mut self,
 34        module: &Module<B>,
 35        pt: &ScalarZnx<DataPt>,
 36        sk: &GLWESecretPrepared<DataSk, B>,
 37        source_xa: &mut Source,
 38        source_xe: &mut Source,
 39        sigma: f64,
 40        scratch: &mut Scratch<B>,
 41    ) where
 42        Module<B>: VecZnxAddScalarInplace
 43            + VecZnxDftAllocBytes
 44            + VecZnxBigNormalize<B>
 45            + VecZnxDftFromVecZnx<B>
 46            + SvpApplyInplace<B>
 47            + VecZnxDftToVecZnxBigConsume<B>
 48            + VecZnxNormalizeTmpBytes
 49            + VecZnxFillUniform
 50            + VecZnxSubABInplace
 51            + VecZnxAddInplace
 52            + VecZnxNormalizeInplace<B>
 53            + VecZnxAddNormal
 54            + VecZnxNormalize<B>
 55            + VecZnxSub,
 56        Scratch<B>: TakeVecZnxDft<B> + ScratchAvailable + TakeVecZnx,
 57    {
 58        #[cfg(debug_assertions)]
 59        {
 60            use backend::hal::api::ZnxInfos;
 61
 62            assert_eq!(
 63                self.rank_in(),
 64                pt.cols(),
 65                "self.rank_in(): {} != pt.cols(): {}",
 66                self.rank_in(),
 67                pt.cols()
 68            );
 69            assert_eq!(
 70                self.rank_out(),
 71                sk.rank(),
 72                "self.rank_out(): {} != sk.rank(): {}",
 73                self.rank_out(),
 74                sk.rank()
 75            );
 76            assert_eq!(self.n(), sk.n());
 77            assert_eq!(pt.n(), sk.n());
 78            assert!(
 79                scratch.available() >= GGLWECiphertext::encrypt_sk_scratch_space(module, sk.n(), self.basek(), self.k()),
 80                "scratch.available: {} < GGLWECiphertext::encrypt_sk_scratch_space(module, self.rank()={}, self.size()={}): {}",
 81                scratch.available(),
 82                self.rank(),
 83                self.size(),
 84                GGLWECiphertext::encrypt_sk_scratch_space(module, sk.n(), self.basek(), self.k())
 85            );
 86            assert!(
 87                self.rows() * self.digits() * self.basek() <= self.k(),
 88                "self.rows() : {} * self.digits() : {} * self.basek() : {} = {} >= self.k() = {}",
 89                self.rows(),
 90                self.digits(),
 91                self.basek(),
 92                self.rows() * self.digits() * self.basek(),
 93                self.k()
 94            );
 95        }
 96
 97        let rows: usize = self.rows();
 98        let digits: usize = self.digits();
 99        let basek: usize = self.basek();
100        let k: usize = self.k();
101        let rank_in: usize = self.rank_in();
102
103        let (mut tmp_pt, scrach_1) = scratch.take_glwe_pt(sk.n(), basek, k);
104        // For each input column (i.e. rank) produces a GGLWE ciphertext of rank_out+1 columns
105        //
106        // Example for ksk rank 2 to rank 3:
107        //
108        // (-(a0*s0 + a1*s1 + a2*s2) + s0', a0, a1, a2)
109        // (-(b0*s0 + b1*s1 + b2*s2) + s0', b0, b1, b2)
110        //
111        // Example ksk rank 2 to rank 1
112        //
113        // (-(a*s) + s0, a)
114        // (-(b*s) + s1, b)
115        (0..rank_in).for_each(|col_i| {
116            (0..rows).for_each(|row_i| {
117                // Adds the scalar_znx_pt to the i-th limb of the vec_znx_pt
118                tmp_pt.data.zero(); // zeroes for next iteration
119                module.vec_znx_add_scalar_inplace(
120                    &mut tmp_pt.data,
121                    0,
122                    (digits - 1) + row_i * digits,
123                    pt,
124                    col_i,
125                );
126                module.vec_znx_normalize_inplace(basek, &mut tmp_pt.data, 0, scrach_1);
127
128                // rlwe encrypt of vec_znx_pt into vec_znx_ct
129                self.at_mut(row_i, col_i)
130                    .encrypt_sk(module, &tmp_pt, sk, source_xa, source_xe, sigma, scrach_1);
131            });
132        });
133    }
134}