poulpy-core 0.6.0

A backend-agnostic crate implementing Module-LWE-based encryption and arithmetic
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132

use poulpy_hal::{
    api::{ModuleN, VecZnxAutomorphismBackend, VecZnxCopyRangeBackend, VecZnxZeroBackend},
    layouts::{
        Backend, Module, ScratchArena, scalar_znx_as_vec_znx_backend_mut_from_mut, scalar_znx_as_vec_znx_backend_ref_from_mut,
        scalar_znx_as_vec_znx_backend_ref_from_ref,
    },
    source::Source,
};

use crate::{
    EncryptionInfos, GGLWEEncryptSk, ScratchArenaTakeCore,
    layouts::{
        GGLWEInfos, GGLWEToBackendMut, GLWESecret, GLWESecretToBackendRef, LWEInfos, LWESecretToBackendRef, Rank,
        prepared::GLWESecretPreparedFactory,
    },
};

#[doc(hidden)]
pub trait GLWEToLWESwitchingKeyEncryptSkDefault<BE: Backend> {
    fn glwe_to_lwe_key_encrypt_sk_tmp_bytes_default<A>(&self, infos: &A) -> usize
    where
        A: GGLWEInfos;

    fn glwe_to_lwe_key_encrypt_sk_default<R, S1, S2, E>(
        &self,
        res: &mut R,
        sk_lwe: &S1,
        sk_glwe: &S2,
        enc_infos: &E,
        source_xe: &mut Source,
        source_xa: &mut Source,
        scratch: &mut ScratchArena<'_, BE>,
    ) where
        S1: LWESecretToBackendRef<BE>,
        S2: GLWESecretToBackendRef<BE>,
        E: EncryptionInfos,
        R: GGLWEToBackendMut<BE> + GGLWEInfos;
}

impl<BE: Backend> GLWEToLWESwitchingKeyEncryptSkDefault<BE> for Module<BE>
where
    Self: ModuleN
        + GGLWEEncryptSk<BE>
        + GLWESecretPreparedFactory<BE>
        + VecZnxAutomorphismBackend<BE>
        + VecZnxCopyRangeBackend<BE>
        + VecZnxZeroBackend<BE>,
{
    fn glwe_to_lwe_key_encrypt_sk_tmp_bytes_default<A>(&self, infos: &A) -> usize
    where
        A: GGLWEInfos,
    {
        assert_eq!(self.n() as u32, infos.n());

        let lvl_0: usize = self.glwe_secret_prepared_bytes_of(infos.rank_in());
        let lvl_1_sk_lwe_as_glwe_src: usize = GLWESecret::bytes_of(self.n().into(), Rank(1));
        let lvl_2_sk_lwe_as_glwe: usize = GLWESecret::bytes_of(self.n().into(), Rank(1));
        let lvl_3_encrypt: usize = self.gglwe_encrypt_sk_tmp_bytes(infos);

        lvl_0 + lvl_1_sk_lwe_as_glwe_src + lvl_2_sk_lwe_as_glwe + lvl_3_encrypt
    }

    #[allow(clippy::too_many_arguments)]
    fn glwe_to_lwe_key_encrypt_sk_default<R, S1, S2, E>(
        &self,
        res: &mut R,
        sk_lwe: &S1,
        sk_glwe: &S2,
        enc_infos: &E,
        source_xe: &mut Source,
        source_xa: &mut Source,
        scratch: &mut ScratchArena<'_, BE>,
    ) where
        S1: LWESecretToBackendRef<BE>,
        S2: GLWESecretToBackendRef<BE>,
        E: EncryptionInfos,
        R: GGLWEToBackendMut<BE> + GGLWEInfos,
    {
        let sk_lwe = sk_lwe.to_backend_ref();
        let sk_glwe = sk_glwe.to_backend_ref();

        assert!(sk_lwe.n().0 <= self.n() as u32);
        assert!(
            scratch.available() >= self.glwe_to_lwe_key_encrypt_sk_tmp_bytes_default(res),
            "scratch.available(): {} < GLWEToLWESwitchingKeyEncryptSk::glwe_to_lwe_key_encrypt_sk_tmp_bytes: {}",
            scratch.available(),
            self.glwe_to_lwe_key_encrypt_sk_tmp_bytes_default(res)
        );

        let scratch = scratch.borrow();
        let (mut sk_lwe_as_glwe_prep, scratch_1) = scratch.take_glwe_secret_prepared_scratch(self, Rank(1));
        let (mut sk_lwe_as_glwe_src, scratch_2) = scratch_1.take_glwe_secret_scratch(self.n().into(), Rank(1));
        let (mut sk_lwe_as_glwe, scratch_3) = scratch_2.take_glwe_secret_scratch(self.n().into(), Rank(1));

        sk_lwe_as_glwe_src.dist = sk_lwe.dist;
        sk_lwe_as_glwe.dist = sk_lwe.dist;
        {
            let mut sk_lwe_as_glwe_src_backend = scalar_znx_as_vec_znx_backend_mut_from_mut::<BE>(&mut sk_lwe_as_glwe_src.data);
            let sk_lwe_backend = scalar_znx_as_vec_znx_backend_ref_from_ref::<BE>(&sk_lwe.data);
            self.vec_znx_zero_backend(&mut sk_lwe_as_glwe_src_backend, 0);
            self.vec_znx_copy_range_backend(
                &mut sk_lwe_as_glwe_src_backend,
                0,
                0,
                0,
                &sk_lwe_backend,
                0,
                0,
                0,
                sk_lwe.n().into(),
            );
        }
        {
            let sk_lwe_as_glwe_src_backend = scalar_znx_as_vec_znx_backend_ref_from_mut::<BE>(&sk_lwe_as_glwe_src.data);
            let mut sk_lwe_as_glwe_backend = scalar_znx_as_vec_znx_backend_mut_from_mut::<BE>(&mut sk_lwe_as_glwe.data);
            self.vec_znx_automorphism_backend(-1, &mut sk_lwe_as_glwe_backend, 0, &sk_lwe_as_glwe_src_backend, 0);
        }
        self.glwe_secret_prepare(&mut sk_lwe_as_glwe_prep, &sk_lwe_as_glwe);

        let (mut enc_scratch, _scratch_4) = scratch_3.split_at(self.gglwe_encrypt_sk_tmp_bytes(res));
        let sk_glwe_data_ref = &sk_glwe.data;
        self.gglwe_encrypt_sk(
            res,
            &sk_glwe_data_ref,
            &sk_lwe_as_glwe_prep,
            enc_infos,
            source_xe,
            source_xa,
            &mut enc_scratch,
        );
    }
}