encryption/
encryption.rs

1use poulpy_backend::cpu_spqlios::FFT64Spqlios;
2use poulpy_core::{
3    GLWESub, SIGMA,
4    layouts::{
5        Base2K, Degree, GLWE, GLWELayout, GLWEPlaintext, GLWEPlaintextLayout, GLWESecret, LWEInfos, Rank, TorusPrecision,
6        prepared::GLWESecretPrepared,
7    },
8};
9use poulpy_hal::{
10    api::{ModuleNew, ScratchOwnedAlloc, ScratchOwnedBorrow, VecZnxFillUniform},
11    layouts::{Module, ScratchOwned},
12    source::Source,
13};
14
15fn main() {
16    // Ring degree
17    let log_n: usize = 10;
18
19    let n: Degree = Degree(1 << log_n);
20
21    // Base-2-k (implicit digit decomposition)
22    let base2k: Base2K = Base2K(14);
23
24    // Ciphertext Torus precision (equivalent to ciphertext modulus)
25    let k_ct: TorusPrecision = TorusPrecision(27);
26
27    // Plaintext Torus precision (equivament to plaintext modulus)
28    let k_pt: TorusPrecision = TorusPrecision(base2k.into());
29
30    // GLWE rank
31    let rank: Rank = Rank(1);
32
33    // Instantiate Module (DFT Tables)
34    let module: Module<FFT64Spqlios> = Module::<FFT64Spqlios>::new(n.0 as u64);
35
36    let glwe_ct_infos: GLWELayout = GLWELayout {
37        n,
38        base2k,
39        k: k_ct,
40        rank,
41    };
42
43    let glwe_pt_infos: GLWEPlaintextLayout = GLWEPlaintextLayout { n, base2k, k: k_pt };
44
45    // Allocates ciphertext & plaintexts
46    let mut ct: GLWE<Vec<u8>> = GLWE::alloc_from_infos(&glwe_ct_infos);
47    let mut pt_want: GLWEPlaintext<Vec<u8>> = GLWEPlaintext::alloc_from_infos(&glwe_pt_infos);
48    let mut pt_have: GLWEPlaintext<Vec<u8>> = GLWEPlaintext::alloc_from_infos(&glwe_pt_infos);
49
50    // CPRNG
51    let mut source_xs: Source = Source::new([0u8; 32]);
52    let mut source_xe: Source = Source::new([1u8; 32]);
53    let mut source_xa: Source = Source::new([2u8; 32]);
54
55    // Scratch space
56    let mut scratch: ScratchOwned<FFT64Spqlios> = ScratchOwned::alloc(
57        GLWE::encrypt_sk_tmp_bytes(&module, &glwe_ct_infos) | GLWE::decrypt_tmp_bytes(&module, &glwe_ct_infos),
58    );
59
60    // Generate secret-key
61    let mut sk: GLWESecret<Vec<u8>> = GLWESecret::alloc_from_infos(&glwe_ct_infos);
62    sk.fill_ternary_prob(0.5, &mut source_xs);
63
64    // Backend-prepared secret
65    let mut sk_prepared: GLWESecretPrepared<Vec<u8>, FFT64Spqlios> = GLWESecretPrepared::alloc(&module, rank);
66    sk_prepared.prepare(&module, &sk);
67
68    // Uniform plaintext
69    module.vec_znx_fill_uniform(base2k.into(), &mut pt_want.data, 0, &mut source_xa);
70
71    // Encryption
72    ct.encrypt_sk(
73        &module,
74        &pt_want,
75        &sk_prepared,
76        &mut source_xa,
77        &mut source_xe,
78        scratch.borrow(),
79    );
80
81    // Decryption
82    ct.decrypt(&module, &mut pt_have, &sk_prepared, scratch.borrow());
83
84    // Diff between pt - Dec(Enc(pt))
85    module.glwe_sub_inplace(&mut pt_want, &pt_have);
86
87    // Ideal vs. actual noise
88    let noise_have: f64 = pt_want.data.std(base2k.into(), 0) * (ct.k().as_u32() as f64).exp2();
89    let noise_want: f64 = SIGMA;
90
91    // Check
92    assert!(noise_have <= noise_want + 0.2);
93}
encryption/encryption.rs

encryption/
encryption.rs
