encryption/
encryption.rs

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

encryption/
encryption.rs
