poulpy_core/encryption/
glwe_to_lwe_ksk.rs

1use poulpy_hal::{
2    api::{
3        ScratchAvailable, SvpApplyDftToDftInplace, SvpPPolAllocBytes, SvpPrepare, TakeScalarZnx, TakeVecZnx, TakeVecZnxDft,
4        VecZnxAddInplace, VecZnxAddNormal, VecZnxAddScalarInplace, VecZnxAutomorphismInplace, VecZnxBigNormalize,
5        VecZnxDftAllocBytes, VecZnxDftApply, VecZnxFillUniform, VecZnxIdftApplyConsume, VecZnxNormalize, VecZnxNormalizeInplace,
6        VecZnxNormalizeTmpBytes, VecZnxSub, VecZnxSubABInplace, VecZnxSwitchRing,
7    },
8    layouts::{Backend, DataMut, DataRef, Module, Scratch, ZnxView, ZnxViewMut, ZnxZero},
9    source::Source,
10};
11
12use crate::{
13    TakeGLWESecret, TakeGLWESecretPrepared,
14    layouts::{GGLWESwitchingKey, GLWESecret, GLWEToLWESwitchingKey, LWESecret, prepared::GLWESecretPrepared},
15};
16
17impl GLWEToLWESwitchingKey<Vec<u8>> {
18    pub fn encrypt_sk_scratch_space<B: Backend>(module: &Module<B>, basek: usize, k: usize, rank_in: usize) -> usize
19    where
20        Module<B>: SvpPPolAllocBytes + VecZnxNormalizeTmpBytes + VecZnxDftAllocBytes + VecZnxNormalizeTmpBytes,
21    {
22        GLWESecretPrepared::bytes_of(module, rank_in)
23            + (GGLWESwitchingKey::encrypt_sk_scratch_space(module, basek, k, rank_in, 1)
24                | GLWESecret::bytes_of(module.n(), rank_in))
25    }
26}
27
28impl<D: DataMut> GLWEToLWESwitchingKey<D> {
29    #[allow(clippy::too_many_arguments)]
30    pub fn encrypt_sk<DLwe, DGlwe, B: Backend>(
31        &mut self,
32        module: &Module<B>,
33        sk_lwe: &LWESecret<DLwe>,
34        sk_glwe: &GLWESecret<DGlwe>,
35        source_xa: &mut Source,
36        source_xe: &mut Source,
37        scratch: &mut Scratch<B>,
38    ) where
39        DLwe: DataRef,
40        DGlwe: DataRef,
41        Module<B>: VecZnxAutomorphismInplace<B>
42            + VecZnxAddScalarInplace
43            + VecZnxDftAllocBytes
44            + VecZnxBigNormalize<B>
45            + VecZnxDftApply<B>
46            + SvpApplyDftToDftInplace<B>
47            + VecZnxIdftApplyConsume<B>
48            + VecZnxNormalizeTmpBytes
49            + VecZnxFillUniform
50            + VecZnxSubABInplace
51            + VecZnxAddInplace
52            + VecZnxNormalizeInplace<B>
53            + VecZnxAddNormal
54            + VecZnxNormalize<B>
55            + VecZnxSub
56            + SvpPrepare<B>
57            + VecZnxSwitchRing
58            + SvpPPolAllocBytes,
59        Scratch<B>: TakeVecZnxDft<B> + ScratchAvailable + TakeVecZnx + TakeScalarZnx + TakeGLWESecretPrepared<B>,
60    {
61        #[cfg(debug_assertions)]
62        {
63            assert!(sk_lwe.n() <= module.n());
64        }
65
66        let (mut sk_lwe_as_glwe, scratch_1) = scratch.take_glwe_secret(sk_glwe.n(), 1);
67        sk_lwe_as_glwe.data.zero();
68        sk_lwe_as_glwe.data.at_mut(0, 0)[..sk_lwe.n()].copy_from_slice(sk_lwe.data.at(0, 0));
69        module.vec_znx_automorphism_inplace(-1, &mut sk_lwe_as_glwe.data.as_vec_znx_mut(), 0, scratch_1);
70
71        self.0.encrypt_sk(
72            module,
73            sk_glwe,
74            &sk_lwe_as_glwe,
75            source_xa,
76            source_xe,
77            scratch_1,
78        );
79    }
80}