encryption/
encryption.rs

1use poulpy_backend::cpu_spqlios::FFT64Spqlios;
2use poulpy_core::{
3    GLWEOperations, SIGMA,
4    layouts::{
5        Base2K, Degree, GLWECiphertext, GLWECiphertextLayout, GLWEPlaintext, GLWEPlaintextLayout, GLWESecret, LWEInfos, Rank,
6        TorusPrecision,
7        prepared::{GLWESecretPrepared, PrepareAlloc},
8    },
9};
10use poulpy_hal::{
11    api::{ModuleNew, ScratchOwnedAlloc, ScratchOwnedBorrow, VecZnxFillUniform},
12    layouts::{Module, ScratchOwned},
13    source::Source,
14};
15
16fn main() {
17    // Ring degree
18    let log_n: usize = 10;
19
20    let n: Degree = Degree(1 << log_n);
21
22    // Base-2-k (implicit digit decomposition)
23    let base2k: Base2K = Base2K(14);
24
25    // Ciphertext Torus precision (equivalent to ciphertext modulus)
26    let k_ct: TorusPrecision = TorusPrecision(27);
27
28    // Plaintext Torus precision (equivament to plaintext modulus)
29    let k_pt: TorusPrecision = TorusPrecision(base2k.into());
30
31    // GLWE rank
32    let rank: Rank = Rank(1);
33
34    // Instantiate Module (DFT Tables)
35    let module: Module<FFT64Spqlios> = Module::<FFT64Spqlios>::new(n.0 as u64);
36
37    let glwe_ct_infos: GLWECiphertextLayout = GLWECiphertextLayout {
38        n,
39        base2k,
40        k: k_ct,
41        rank,
42    };
43
44    let glwe_pt_infos: GLWEPlaintextLayout = GLWEPlaintextLayout { n, base2k, k: k_pt };
45
46    // Allocates ciphertext & plaintexts
47    let mut ct: GLWECiphertext<Vec<u8>> = GLWECiphertext::alloc(&glwe_ct_infos);
48    let mut pt_want: GLWEPlaintext<Vec<u8>> = GLWEPlaintext::alloc(&glwe_pt_infos);
49    let mut pt_have: GLWEPlaintext<Vec<u8>> = GLWEPlaintext::alloc(&glwe_pt_infos);
50
51    // CPRNG
52    let mut source_xs: Source = Source::new([0u8; 32]);
53    let mut source_xe: Source = Source::new([1u8; 32]);
54    let mut source_xa: Source = Source::new([2u8; 32]);
55
56    // Scratch space
57    let mut scratch: ScratchOwned<FFT64Spqlios> = ScratchOwned::alloc(
58        GLWECiphertext::encrypt_sk_scratch_space(&module, &glwe_ct_infos)
59            | GLWECiphertext::decrypt_scratch_space(&module, &glwe_ct_infos),
60    );
61
62    // Generate secret-key
63    let mut sk: GLWESecret<Vec<u8>> = GLWESecret::alloc(&glwe_ct_infos);
64    sk.fill_ternary_prob(0.5, &mut source_xs);
65
66    // Backend-prepared secret
67    let sk_prepared: GLWESecretPrepared<Vec<u8>, FFT64Spqlios> = sk.prepare_alloc(&module, scratch.borrow());
68
69    // Uniform plaintext
70    module.vec_znx_fill_uniform(base2k.into(), &mut pt_want.data, 0, &mut source_xa);
71
72    // Encryption
73    ct.encrypt_sk(
74        &module,
75        &pt_want,
76        &sk_prepared,
77        &mut source_xa,
78        &mut source_xe,
79        scratch.borrow(),
80    );
81
82    // Decryption
83    ct.decrypt(&module, &mut pt_have, &sk_prepared, scratch.borrow());
84
85    // Diff between pt - Dec(Enc(pt))
86    pt_want.sub_inplace_ab(&module, &pt_have);
87
88    // Ideal vs. actual noise
89    let noise_have: f64 = pt_want.data.std(base2k.into(), 0) * (ct.k().as_u32() as f64).exp2();
90    let noise_want: f64 = SIGMA;
91
92    // Check
93    assert!(noise_have <= noise_want + 0.2);
94}
encryption/encryption.rs

encryption/
encryption.rs
