phantom-zone/src/bool/print_noise.rs
src/bool/print_noise.rsRaw
1use std::{fmt::Debug, iter::Sum};
2
3use itertools::izip;
4use num_traits::{FromPrimitive, PrimInt, Zero};
5use rand_distr::uniform::SampleUniform;
6
7use crate::{
8 backend::{GetModulus, Modulus},
9 decomposer::{Decomposer, NumInfo, RlweDecomposer},
10 lwe::{decrypt_lwe, lwe_key_switch},
11 parameters::{BoolParameters, CiphertextModulus},
12 random::{DefaultSecureRng, RandomFillUniformInModulus},
13 rgsw::{
14 decrypt_rlwe, rlwe_auto, rlwe_auto_scratch_rows, RlweCiphertextMutRef, RlweKskRef,
15 RuntimeScratchMutRef,
16 },
17 utils::{encode_x_pow_si_with_emebedding_factor, tests::Stats, TryConvertFrom1},
18 ArithmeticOps, ClientKey, MatrixEntity, MatrixMut, ModInit, Ntt, NttInit, RowEntity, RowMut,
19 VectorOps,
20};
21
22use super::keys::tests::{ideal_sk_lwe, ideal_sk_rlwe};
23
24pub(crate) trait CollectRuntimeServerKeyStats {
25 type M;
26 /// RGSW ciphertext X^{s[s_index]} in evaluation domain where `s` the LWE
27 /// secret
28 fn rgsw_cts_lwe_si(&self, s_index: usize) -> &Self::M;
29 /// Auto key in evaluation domain for automorphism g^k. For auto key for
30 /// automorphism corresponding to -g, set k = 0
31 fn galois_key_for_auto(&self, k: usize) -> &Self::M;
32 /// LWE key switching key
33 fn lwe_ksk(&self) -> &Self::M;
34}
35
36#[derive(Default)]
37struct ServerKeyStats<T> {
38 /// Distribution of noise in RGSW ciphertexts
39 ///
40 /// We collect statistics for RLWE'(-sm) separately from RLWE'(m) because
41 /// non-interactive protocol differents between the two. Although we expect
42 /// the distribution of noise in both to be the same.
43 brk_rgsw_cts: (Stats<T>, Stats<T>),
44 /// Distribtion of noise added to RLWE ciphertext after automorphism using
45 /// Server auto keys.
46 post_1_auto: Stats<T>,
47 /// Distribution of noise added in LWE key switching from LWE_{q, s} to
48 /// LWE_{q, z} where `z` is ideal LWE secret and `s` is ideal RLWE secret
49 /// using Server's LWE key switching key.
50 post_lwe_key_switch: Stats<T>,
51}
52
53impl<T: PrimInt + FromPrimitive + Debug + Sum> ServerKeyStats<T>
54where
55 T: for<'a> Sum<&'a T>,
56{
57 fn new() -> Self {
58 ServerKeyStats {
59 brk_rgsw_cts: (Stats::default(), Stats::default()),
60 post_1_auto: Stats::default(),
61 post_lwe_key_switch: Stats::default(),
62 }
63 }
64
65 fn add_noise_brk_rgsw_cts_nsm(&mut self, noise: &[T]) {
66 self.brk_rgsw_cts.0.add_many_samples(noise);
67 }
68
69 fn add_noise_brk_rgsw_cts_m(&mut self, noise: &[T]) {
70 self.brk_rgsw_cts.1.add_many_samples(noise);
71 }
72
73 fn add_noise_post_1_auto(&mut self, noise: &[T]) {
74 self.post_1_auto.add_many_samples(&noise);
75 }
76
77 fn add_noise_post_kwe_key_switch(&mut self, noise: &[T]) {
78 self.post_lwe_key_switch.add_many_samples(&noise);
79 }
80
81 fn merge_in(&mut self, other: &Self) {
82 self.brk_rgsw_cts.0.merge_in(&other.brk_rgsw_cts.0);
83 self.brk_rgsw_cts.1.merge_in(&other.brk_rgsw_cts.1);
84
85 self.post_1_auto.merge_in(&other.post_1_auto);
86 self.post_lwe_key_switch
87 .merge_in(&other.post_lwe_key_switch);
88 }
89}
90
91fn collect_server_key_stats<
92 M: MatrixEntity + MatrixMut,
93 D: Decomposer<Element = M::MatElement>,
94 NttOp: NttInit<CiphertextModulus<M::MatElement>> + Ntt<Element = M::MatElement>,
95 ModOp: VectorOps<Element = M::MatElement>
96 + ArithmeticOps<Element = M::MatElement>
97 + ModInit<M = CiphertextModulus<M::MatElement>>
98 + GetModulus<M = CiphertextModulus<M::MatElement>, Element = M::MatElement>,
99 S: CollectRuntimeServerKeyStats<M = M>,
100>(
101 parameters: BoolParameters<M::MatElement>,
102 client_keys: &[ClientKey],
103 server_key: &S,
104) -> ServerKeyStats<i64>
105where
106 M::R: RowMut + RowEntity + TryConvertFrom1<[i32], CiphertextModulus<M::MatElement>> + Clone,
107 M::MatElement: Copy + PrimInt + FromPrimitive + SampleUniform + Zero + Debug + NumInfo,
108{
109 let ideal_sk_rlwe = ideal_sk_rlwe(client_keys);
110 let ideal_sk_lwe = ideal_sk_lwe(client_keys);
111
112 let embedding_factor = (2 * parameters.rlwe_n().0) / parameters.br_q();
113 let rlwe_n = parameters.rlwe_n().0;
114 let rlwe_q = parameters.rlwe_q();
115 let lwe_q = parameters.lwe_q();
116 let rlwe_modop = ModOp::new(rlwe_q.clone());
117 let rlwe_nttop = NttOp::new(rlwe_q, rlwe_n);
118 let lwe_modop = ModOp::new(*parameters.lwe_q());
119
120 let rlwe_x_rgsw_decomposer = parameters.rlwe_rgsw_decomposer::<D>();
121 let (rlwe_x_rgsw_gadget_a, rlwe_x_rgsw_gadget_b) = (
122 rlwe_x_rgsw_decomposer.a().gadget_vector(),
123 rlwe_x_rgsw_decomposer.b().gadget_vector(),
124 );
125
126 let lwe_ks_decomposer = parameters.lwe_decomposer::<D>();
127
128 let mut server_key_stats = ServerKeyStats::new();
129
130 let mut rng = DefaultSecureRng::new();
131
132 // RGSW ciphertext noise
133 // Check noise in RGSW ciphertexts of ideal LWE secret elements
134 {
135 ideal_sk_lwe.iter().enumerate().for_each(|(s_index, s_i)| {
136 let rgsw_ct_i = server_key.rgsw_cts_lwe_si(s_index);
137
138 // X^{s[i]}
139 let m_si = encode_x_pow_si_with_emebedding_factor::<M::R, _>(
140 *s_i,
141 embedding_factor,
142 rlwe_n,
143 rlwe_q,
144 );
145
146 // RLWE'(-sm)
147 let mut neg_s_eval = M::R::try_convert_from(ideal_sk_rlwe.as_slice(), rlwe_q);
148 rlwe_modop.elwise_neg_mut(neg_s_eval.as_mut());
149 rlwe_nttop.forward(neg_s_eval.as_mut());
150
151 for j in 0..rlwe_x_rgsw_decomposer.a().decomposition_count().0 {
152 // RLWE(B^{j} * -s[X]*X^{s_lwe[i]})
153
154 // -s[X]*X^{s_lwe[i]}*B_j
155 let mut m_ideal = m_si.clone();
156 rlwe_nttop.forward(m_ideal.as_mut());
157 rlwe_modop.elwise_mul_mut(m_ideal.as_mut(), neg_s_eval.as_ref());
158 rlwe_nttop.backward(m_ideal.as_mut());
159 rlwe_modop.elwise_scalar_mul_mut(m_ideal.as_mut(), &rlwe_x_rgsw_gadget_a[j]);
160
161 // RLWE(-s*X^{s_lwe[i]}*B_j)
162 let mut rlwe_ct = M::zeros(2, rlwe_n);
163 rlwe_ct
164 .get_row_mut(0)
165 .copy_from_slice(rgsw_ct_i.get_row_slice(j));
166 rlwe_ct.get_row_mut(1).copy_from_slice(
167 rgsw_ct_i.get_row_slice(j + rlwe_x_rgsw_decomposer.a().decomposition_count().0),
168 );
169 // RGSW ciphertexts are in eval domain. We put RLWE ciphertexts back in
170 // coefficient domain
171 rlwe_ct
172 .iter_rows_mut()
173 .for_each(|r| rlwe_nttop.backward(r.as_mut()));
174
175 let mut m_back = M::R::zeros(rlwe_n);
176 decrypt_rlwe(
177 &rlwe_ct,
178 &ideal_sk_rlwe,
179 &mut m_back,
180 &rlwe_nttop,
181 &rlwe_modop,
182 );
183
184 // diff
185 rlwe_modop.elwise_sub_mut(m_back.as_mut(), m_ideal.as_ref());
186 server_key_stats.add_noise_brk_rgsw_cts_nsm(&Vec::<i64>::try_convert_from(
187 m_back.as_ref(),
188 rlwe_q,
189 ));
190 }
191
192 // RLWE'(m)
193 for j in 0..rlwe_x_rgsw_decomposer.b().decomposition_count().0 {
194 // RLWE(B^{j} * X^{s_lwe[i]})
195
196 // X^{s_lwe[i]}*B_j
197 let mut m_ideal = m_si.clone();
198 rlwe_modop.elwise_scalar_mul_mut(m_ideal.as_mut(), &rlwe_x_rgsw_gadget_b[j]);
199
200 // RLWE(X^{s_lwe[i]}*B_j)
201 let mut rlwe_ct = M::zeros(2, rlwe_n);
202 rlwe_ct.get_row_mut(0).copy_from_slice(
203 rgsw_ct_i.get_row_slice(
204 j + (2 * rlwe_x_rgsw_decomposer.a().decomposition_count().0),
205 ),
206 );
207 rlwe_ct
208 .get_row_mut(1)
209 .copy_from_slice(rgsw_ct_i.get_row_slice(
210 j + (2 * rlwe_x_rgsw_decomposer.a().decomposition_count().0)
211 + rlwe_x_rgsw_decomposer.b().decomposition_count().0,
212 ));
213 rlwe_ct
214 .iter_rows_mut()
215 .for_each(|r| rlwe_nttop.backward(r.as_mut()));
216
217 let mut m_back = M::R::zeros(rlwe_n);
218 decrypt_rlwe(
219 &rlwe_ct,
220 &ideal_sk_rlwe,
221 &mut m_back,
222 &rlwe_nttop,
223 &rlwe_modop,
224 );
225
226 // diff
227 rlwe_modop.elwise_sub_mut(m_back.as_mut(), m_ideal.as_ref());
228 server_key_stats.add_noise_brk_rgsw_cts_m(&Vec::<i64>::try_convert_from(
229 m_back.as_ref(),
230 rlwe_q,
231 ));
232 }
233 });
234 }
235
236 // Noise in ciphertext after 1 auto
237 // For each auto key g^k. Sample random polynomial m(X) and multiply with
238 // -s(X^{g^k}) using key corresponding to auto g^k. Then check the noise in
239 // resutling RLWE(m(X) * -s(X^{g^k}))
240 {
241 let neg_s = {
242 let mut s = M::R::try_convert_from(ideal_sk_rlwe.as_slice(), rlwe_q);
243 rlwe_modop.elwise_neg_mut(s.as_mut());
244 s
245 };
246 let g = parameters.g();
247 let br_q = parameters.br_q();
248 let g_dlogs = parameters.auto_element_dlogs();
249 let auto_decomposer = parameters.auto_decomposer::<D>();
250 let mut scratch_matrix = M::zeros(rlwe_auto_scratch_rows(&auto_decomposer), rlwe_n);
251 let mut scratch_matrix_ref = RuntimeScratchMutRef::new(scratch_matrix.as_mut());
252
253 g_dlogs.iter().for_each(|k| {
254 let g_pow_k = if *k == 0 {
255 -(g as isize)
256 } else {
257 (g.pow(*k as u32) % br_q) as isize
258 };
259
260 // Send s(X) -> s(X^{g^k})
261 let (auto_index_map, auto_sign_map) = crate::rgsw::generate_auto_map(rlwe_n, g_pow_k);
262 let mut neg_s_g_k = M::R::zeros(rlwe_n);
263 izip!(
264 neg_s.as_ref().iter(),
265 auto_index_map.iter(),
266 auto_sign_map.iter()
267 )
268 .for_each(|(el, to_index, to_sign)| {
269 if !to_sign {
270 neg_s_g_k.as_mut()[*to_index] = rlwe_modop.neg(el);
271 } else {
272 neg_s_g_k.as_mut()[*to_index] = *el;
273 }
274 });
275
276 let mut m = M::R::zeros(rlwe_n);
277 RandomFillUniformInModulus::random_fill(&mut rng, rlwe_q, m.as_mut());
278
279 // We want -m(X^{g^k})s(X^{g^k}) after key switch
280 let want_m = {
281 let mut m_g_k_eval = M::R::zeros(rlwe_n);
282 // send m(X) -> m(X^{g^k})
283 izip!(
284 m.as_ref().iter(),
285 auto_index_map.iter(),
286 auto_sign_map.iter()
287 )
288 .for_each(|(el, to_index, to_sign)| {
289 if !to_sign {
290 m_g_k_eval.as_mut()[*to_index] = rlwe_modop.neg(el);
291 } else {
292 m_g_k_eval.as_mut()[*to_index] = *el;
293 }
294 });
295
296 rlwe_nttop.forward(m_g_k_eval.as_mut());
297 let mut s_g_k = neg_s_g_k.clone();
298 rlwe_nttop.forward(s_g_k.as_mut());
299 rlwe_modop.elwise_mul_mut(m_g_k_eval.as_mut(), s_g_k.as_ref());
300 rlwe_nttop.backward(m_g_k_eval.as_mut());
301 m_g_k_eval
302 };
303
304 // RLWE auto sends part A, A(X), of RLWE to A(X^{g^k}) and then multiplies it
305 // with -s(X^{g^k}) using auto key. Deliberately set RLWE = (0, m(X))
306 // (ie. m in part A) to get back RLWE(-m(X^{g^k})s(X^{g^k}))
307 let mut rlwe = M::zeros(2, rlwe_n);
308 rlwe.get_row_mut(0).copy_from_slice(m.as_ref());
309
310 rlwe_auto(
311 &mut RlweCiphertextMutRef::new(rlwe.as_mut()),
312 &RlweKskRef::new(
313 server_key.galois_key_for_auto(*k).as_ref(),
314 auto_decomposer.decomposition_count().0,
315 ),
316 &mut scratch_matrix_ref,
317 &auto_index_map,
318 &auto_sign_map,
319 &rlwe_modop,
320 &rlwe_nttop,
321 &auto_decomposer,
322 false,
323 );
324
325 // decrypt RLWE(-m(X)s(X^{g^k]}))
326 let mut back_m = M::R::zeros(rlwe_n);
327 decrypt_rlwe(&rlwe, &ideal_sk_rlwe, &mut back_m, &rlwe_nttop, &rlwe_modop);
328
329 // check difference
330 let mut diff = back_m;
331 rlwe_modop.elwise_sub_mut(diff.as_mut(), want_m.as_ref());
332 server_key_stats
333 .add_noise_post_1_auto(&Vec::<i64>::try_convert_from(diff.as_ref(), rlwe_q));
334 });
335
336 // sample random m
337
338 // key switch
339 }
340
341 // LWE Key switch
342 // LWE key switches LWE_in = LWE_{Q_ks,N, s}(m) = (b, a_0, ... a_N) -> LWE_out =
343 // LWE_{Q_{ks}, n, z}(m) = (b', a'_0, ..., a'n)
344 // If LWE_in = (0, a = {a_0, ..., a_N}), then LWE_out = LWE(-a \cdot s_{rlwe})
345 for _ in 0..100 {
346 let mut lwe_in = M::R::zeros(rlwe_n + 1);
347 RandomFillUniformInModulus::random_fill(&mut rng, lwe_q, &mut lwe_in.as_mut()[1..]);
348
349 // Key switch
350 let mut lwe_out = M::R::zeros(parameters.lwe_n().0 + 1);
351 lwe_key_switch(
352 &mut lwe_out,
353 &lwe_in,
354 server_key.lwe_ksk(),
355 &lwe_modop,
356 &lwe_ks_decomposer,
357 );
358
359 // -a \cdot s
360 let mut want_m = M::MatElement::zero();
361 izip!(lwe_in.as_ref().iter().skip(1), ideal_sk_rlwe.iter()).for_each(|(a, b)| {
362 want_m = lwe_modop.add(
363 &want_m,
364 &lwe_modop.mul(a, &lwe_q.map_element_from_i64(*b as i64)),
365 );
366 });
367 want_m = lwe_modop.neg(&want_m);
368
369 // decrypt lwe out
370 let back_m = decrypt_lwe(&lwe_out, &ideal_sk_lwe, &lwe_modop);
371
372 let noise = lwe_modop.sub(&want_m, &back_m);
373 server_key_stats.add_noise_post_kwe_key_switch(&vec![lwe_q.map_element_to_i64(&noise)]);
374 }
375
376 server_key_stats
377 // Auto keys noise
378
379 // Ksk noise
380}
381
382#[cfg(test)]
383mod tests {
384 use itertools::Itertools;
385
386 #[test]
387 #[cfg(feature = "interactive_mp")]
388 fn interactive_key_noise() {
389 use crate::{
390 aggregate_public_key_shares, aggregate_server_key_shares,
391 bool::{
392 evaluator::InteractiveMultiPartyCrs,
393 keys::{key_size::KeySize, ServerKeyEvaluationDomain},
394 },
395 collective_pk_share, collective_server_key_share, gen_client_key,
396 parameters::CiphertextModulus,
397 random::DefaultSecureRng,
398 set_common_reference_seed, set_parameter_set,
399 utils::WithLocal,
400 BoolEvaluator, DefaultDecomposer, ModularOpsU64, NttBackendU64,
401 };
402
403 use super::*;
404
405 set_parameter_set(crate::ParameterSelector::InteractiveLTE8Party);
406 set_common_reference_seed(InteractiveMultiPartyCrs::random().seed);
407 let parties = 8;
408
409 let mut server_key_stats = ServerKeyStats::default();
410 let mut server_key_share_size = 0usize;
411
412 for i in 0..2 {
413 let cks = (0..parties).map(|_| gen_client_key()).collect_vec();
414 let pk_shares = cks.iter().map(|k| collective_pk_share(k)).collect_vec();
415
416 let pk = aggregate_public_key_shares(&pk_shares);
417 let server_key_shares = cks
418 .iter()
419 .enumerate()
420 .map(|(index, k)| collective_server_key_share(k, index, parties, &pk))
421 .collect_vec();
422
423 // In 0th iteration measure server key size
424 if i == 0 {
425 // Server key share size of user with last id may not equal server key share
426 // sizes of other users if LWE dimension does not divides number of parties.
427 server_key_share_size = std::cmp::max(
428 server_key_shares.first().unwrap().size(),
429 server_key_shares.last().unwrap().size(),
430 );
431 }
432
433 // println!("Size: {}", server_key_shares[0].size());
434 let seeded_server_key = aggregate_server_key_shares(&server_key_shares);
435 let server_key_eval =
436 ServerKeyEvaluationDomain::<_, _, DefaultSecureRng, NttBackendU64>::from(
437 &seeded_server_key,
438 );
439
440 let parameters = BoolEvaluator::with_local(|e| e.parameters().clone());
441 server_key_stats.merge_in(&collect_server_key_stats::<
442 _,
443 DefaultDecomposer<u64>,
444 NttBackendU64,
445 ModularOpsU64<CiphertextModulus<u64>>,
446 _,
447 >(parameters, &cks, &server_key_eval));
448 }
449
450 println!(
451 "Common reference seeded server key share key size: {} Bits",
452 server_key_share_size
453 );
454
455 println!(
456 "Rgsw nsm std log2 {}",
457 server_key_stats.brk_rgsw_cts.0.std_dev().log2()
458 );
459 println!(
460 "Rgsw m std log2 {}",
461 server_key_stats.brk_rgsw_cts.1.std_dev().log2()
462 );
463 println!(
464 "rlwe post 1 auto std log2 {}",
465 server_key_stats.post_1_auto.std_dev().log2()
466 );
467 println!(
468 "key switching noise rlwe secret s to lwe secret z std log2 {}",
469 server_key_stats.post_lwe_key_switch.std_dev().log2()
470 );
471 }
472
473 const K: usize = 10;
474
475 #[test]
476 #[cfg(feature = "interactive_mp")]
477 fn interactive_mp_bool_gates() {
478 use rand::{thread_rng, RngCore};
479
480 use crate::{
481 aggregate_public_key_shares, aggregate_server_key_shares,
482 backend::Modulus,
483 bool::{
484 keys::{
485 tests::{ideal_sk_rlwe, measure_noise_lwe},
486 ServerKeyEvaluationDomain,
487 },
488 print_noise::collect_server_key_stats,
489 },
490 collective_pk_share, collective_server_key_share, gen_client_key,
491 parameters::CiphertextModulus,
492 random::DefaultSecureRng,
493 set_common_reference_seed, set_parameter_set,
494 utils::{tests::Stats, Global, WithLocal},
495 BoolEvaluator, BooleanGates, DefaultDecomposer, Encoder, Encryptor, ModInit,
496 ModularOpsU64, MultiPartyDecryptor, NttBackendU64, ParameterSelector, RuntimeServerKey,
497 };
498
499 set_parameter_set(ParameterSelector::InteractiveLTE8Party);
500
501 let mut seed = [0u8; 32];
502 thread_rng().fill_bytes(&mut seed);
503 set_common_reference_seed(seed);
504
505 let no_of_parties = 8;
506
507 let cks = (0..no_of_parties).map(|_| gen_client_key()).collect_vec();
508
509 // round 1
510 let pk_shares = cks.iter().map(|k| collective_pk_share(k)).collect_vec();
511
512 let pk = aggregate_public_key_shares(&pk_shares);
513
514 // round 2
515 let server_key_shares = cks
516 .iter()
517 .enumerate()
518 .map(|(user_id, k)| collective_server_key_share(k, user_id, no_of_parties, &pk))
519 .collect_vec();
520
521 let server_key = aggregate_server_key_shares(&server_key_shares);
522 server_key.set_server_key();
523
524 let mut m0 = false;
525 let mut m1 = true;
526
527 let mut ct0 = pk.encrypt(&m0);
528 let mut ct1 = pk.encrypt(&m1);
529
530 let ideal_sk_rlwe = ideal_sk_rlwe(&cks);
531 let parameters = BoolEvaluator::with_local(|e| e.parameters().clone());
532 let rlwe_modop = ModularOpsU64::new(*parameters.rlwe_q());
533
534 let mut stats = Stats::new();
535
536 for _ in 0..K {
537 // let now = std::time::Instant::now();
538 let ct_out =
539 BoolEvaluator::with_local_mut(|e| e.xor(&ct0, &ct1, RuntimeServerKey::global()));
540 // println!("Time: {:?}", now.elapsed());
541
542 let m_expected = m0 ^ m1;
543
544 let decryption_shares = cks
545 .iter()
546 .map(|k| k.gen_decryption_share(&ct_out))
547 .collect_vec();
548 let m_out = cks[0].aggregate_decryption_shares(&ct_out, &decryption_shares);
549
550 assert!(m_out == m_expected, "Expected {m_expected}, got {m_out}");
551
552 {
553 let noise = measure_noise_lwe(
554 &ct_out,
555 parameters.rlwe_q().encode(m_expected),
556 &ideal_sk_rlwe,
557 &rlwe_modop,
558 );
559 stats.add_sample(parameters.rlwe_q().map_element_to_i64(&noise));
560 }
561
562 m1 = m0;
563 m0 = m_expected;
564
565 ct1 = ct0;
566 ct0 = ct_out;
567 }
568
569 let server_key_stats = collect_server_key_stats::<
570 _,
571 DefaultDecomposer<u64>,
572 NttBackendU64,
573 ModularOpsU64<CiphertextModulus<u64>>,
574 _,
575 >(
576 parameters,
577 &cks,
578 &ServerKeyEvaluationDomain::<_, _, DefaultSecureRng, NttBackendU64>::from(&server_key),
579 );
580
581 println!("## Bootstrapping Statistics ##");
582 println!("Bootstrapped ciphertext noise std_dev: {}", stats.std_dev());
583
584 println!("## Key Statistics ##");
585 println!(
586 "Rgsw nsm std_dev {}",
587 server_key_stats.brk_rgsw_cts.0.std_dev()
588 );
589 println!(
590 "Rgsw m std_dev {}",
591 server_key_stats.brk_rgsw_cts.1.std_dev()
592 );
593 println!(
594 "rlwe post 1 auto std_dev {}",
595 server_key_stats.post_1_auto.std_dev()
596 );
597 println!(
598 "key switching noise rlwe secret s to lwe secret z std_dev {}",
599 server_key_stats.post_lwe_key_switch.std_dev()
600 );
601 println!();
602 }
603
604 #[test]
605 #[cfg(feature = "non_interactive_mp")]
606 fn non_interactive_mp_bool_gates() {
607 use rand::{thread_rng, RngCore};
608
609 use crate::{
610 aggregate_server_key_shares,
611 backend::Modulus,
612 bool::{
613 keys::{
614 tests::{ideal_sk_rlwe, measure_noise_lwe},
615 NonInteractiveServerKeyEvaluationDomain,
616 },
617 print_noise::collect_server_key_stats,
618 },
619 gen_client_key, gen_server_key_share,
620 parameters::CiphertextModulus,
621 random::DefaultSecureRng,
622 set_common_reference_seed, set_parameter_set,
623 utils::{tests::Stats, Global, WithLocal},
624 BoolEvaluator, BooleanGates, DefaultDecomposer, Encoder, Encryptor, KeySwitchWithId,
625 ModInit, ModularOpsU64, MultiPartyDecryptor, NttBackendU64, ParameterSelector,
626 RuntimeServerKey, SampleExtractor,
627 };
628
629 set_parameter_set(ParameterSelector::NonInteractiveLTE8Party);
630 let mut seed = [0u8; 32];
631 thread_rng().fill_bytes(&mut seed);
632 set_common_reference_seed(seed);
633
634 let parties = 8;
635
636 let cks = (0..parties).map(|_| gen_client_key()).collect_vec();
637
638 let server_key_shares = cks
639 .iter()
640 .enumerate()
641 .map(|(user_index, ck)| gen_server_key_share(user_index, parties, ck))
642 .collect_vec();
643
644 let seeded_server_key = aggregate_server_key_shares(&server_key_shares);
645 seeded_server_key.set_server_key();
646
647 let parameters = BoolEvaluator::with_local(|e| e.parameters().clone());
648 let rlwe_modop = ModularOpsU64::new(*parameters.rlwe_q());
649
650 let ideal_sk_rlwe = ideal_sk_rlwe(&cks);
651
652 let mut m0 = false;
653 let mut m1 = true;
654
655 let mut ct0 = {
656 cks[0]
657 .encrypt(vec![m0].as_slice())
658 .unseed::<Vec<Vec<u64>>>()
659 .key_switch(0)
660 .extract_at(0)
661 .data
662 };
663 let mut ct1 = {
664 cks[1]
665 .encrypt(vec![m1].as_slice())
666 .unseed::<Vec<Vec<u64>>>()
667 .key_switch(1)
668 .extract_at(0)
669 .data
670 };
671
672 let mut stats = Stats::new();
673
674 for _ in 0..K {
675 // let now = std::time::Instant::now();
676 let ct_out =
677 BoolEvaluator::with_local_mut(|e| e.xor(&ct0, &ct1, RuntimeServerKey::global()));
678 // println!("Time: {:?}", now.elapsed());
679
680 let decryption_shares = cks
681 .iter()
682 .map(|k| k.gen_decryption_share(&ct_out))
683 .collect_vec();
684 let m_out = cks[0].aggregate_decryption_shares(&ct_out, &decryption_shares);
685
686 let m_expected = m0 ^ m1;
687
688 {
689 let noise = measure_noise_lwe(
690 &ct_out,
691 parameters.rlwe_q().encode(m_expected),
692 &ideal_sk_rlwe,
693 &rlwe_modop,
694 );
695 stats.add_sample(parameters.rlwe_q().map_element_to_i64(&noise));
696 }
697
698 assert!(m_out == m_expected, "Expected {m_expected} but got {m_out}");
699
700 m1 = m0;
701 m0 = m_out;
702
703 ct1 = ct0;
704 ct0 = ct_out;
705 }
706
707 // server key statistics
708 let server_key_stats = collect_server_key_stats::<
709 _,
710 DefaultDecomposer<u64>,
711 NttBackendU64,
712 ModularOpsU64<CiphertextModulus<u64>>,
713 _,
714 >(
715 parameters,
716 &cks,
717 &NonInteractiveServerKeyEvaluationDomain::<_, _, DefaultSecureRng, NttBackendU64>::from(
718 &seeded_server_key,
719 ),
720 );
721
722 println!("## Bootstrapping Statistics ##");
723 println!("Bootstrapped ciphertext noise std_dev: {}", stats.std_dev());
724
725 println!("## Key Statistics ##");
726 println!(
727 "Rgsw nsm std_dev {}",
728 server_key_stats.brk_rgsw_cts.0.std_dev()
729 );
730 println!(
731 "Rgsw m std_dev {}",
732 server_key_stats.brk_rgsw_cts.1.std_dev()
733 );
734 println!(
735 "rlwe post 1 auto std_dev {}",
736 server_key_stats.post_1_auto.std_dev()
737 );
738 println!(
739 "key switching noise rlwe secret s to lwe secret z std_dev {}",
740 server_key_stats.post_lwe_key_switch.std_dev()
741 );
742 println!();
743 }
744
745 #[test]
746 #[cfg(feature = "non_interactive_mp")]
747 fn non_interactive_key_noise() {
748 use crate::{
749 aggregate_server_key_shares,
750 bool::{
751 evaluator::NonInteractiveMultiPartyCrs,
752 keys::{key_size::KeySize, NonInteractiveServerKeyEvaluationDomain},
753 },
754 decomposer::DefaultDecomposer,
755 gen_client_key, gen_server_key_share,
756 parameters::CiphertextModulus,
757 random::DefaultSecureRng,
758 set_common_reference_seed, set_parameter_set,
759 utils::WithLocal,
760 BoolEvaluator, ModularOpsU64, NttBackendU64,
761 };
762
763 use super::*;
764
765 set_parameter_set(crate::ParameterSelector::NonInteractiveLTE8Party);
766 set_common_reference_seed(NonInteractiveMultiPartyCrs::random().seed);
767 let parties = 8;
768
769 let mut server_key_stats = ServerKeyStats::default();
770 let mut server_key_share_size = 0;
771 for i in 0..2 {
772 let cks = (0..parties).map(|_| gen_client_key()).collect_vec();
773 let server_key_shares = cks
774 .iter()
775 .enumerate()
776 .map(|(user_id, k)| gen_server_key_share(user_id, parties, k))
777 .collect_vec();
778
779 // Collect server key size in the 0th iteration
780 if i == 0 {
781 // Server key share size may differ for user with last id from
782 // the share size of other users if the LWE dimension `n` is not
783 // divisible by no. of parties.
784 server_key_share_size = std::cmp::max(
785 server_key_shares.first().unwrap().size(),
786 server_key_shares.last().unwrap().size(),
787 );
788 }
789
790 let server_key = aggregate_server_key_shares(&server_key_shares);
791
792 let server_key_eval = NonInteractiveServerKeyEvaluationDomain::<
793 _,
794 _,
795 DefaultSecureRng,
796 NttBackendU64,
797 >::from(&server_key);
798
799 let parameters = BoolEvaluator::with_local(|e| e.parameters().clone());
800 server_key_stats.merge_in(&collect_server_key_stats::<
801 _,
802 DefaultDecomposer<u64>,
803 NttBackendU64,
804 ModularOpsU64<CiphertextModulus<u64>>,
805 _,
806 >(parameters, &cks, &server_key_eval));
807 }
808
809 println!(
810 "Common reference seeded server key share key size: {} Bits",
811 server_key_share_size
812 );
813 println!(
814 "Rgsw nsm std log2 {}",
815 server_key_stats.brk_rgsw_cts.0.std_dev().abs().log2()
816 );
817 println!(
818 "Rgsw m std log2 {}",
819 server_key_stats.brk_rgsw_cts.1.std_dev().abs().log2()
820 );
821 println!(
822 "rlwe post 1 auto std log2 {}",
823 server_key_stats.post_1_auto.std_dev().abs().log2()
824 );
825 println!(
826 "key switching noise rlwe secret s to lwe secret z std log2 {}",
827 server_key_stats.post_lwe_key_switch.std_dev().abs().log2()
828 );
829 }
830
831 #[test]
832 #[cfg(feature = "non_interactive_mp")]
833 fn enc_under_sk_and_key_switch() {
834 use rand::{thread_rng, Rng};
835
836 use crate::{
837 aggregate_server_key_shares,
838 bool::keys::tests::ideal_sk_rlwe,
839 gen_client_key, gen_server_key_share,
840 rgsw::decrypt_rlwe,
841 set_common_reference_seed, set_parameter_set,
842 utils::{tests::Stats, TryConvertFrom1, WithLocal},
843 BoolEvaluator, Encoder, Encryptor, KeySwitchWithId, ModInit, ModularOpsU64,
844 NttBackendU64, NttInit, ParameterSelector, VectorOps,
845 };
846
847 set_parameter_set(ParameterSelector::NonInteractiveLTE2Party);
848 set_common_reference_seed([2; 32]);
849
850 let parties = 2;
851
852 let cks = (0..parties).map(|_| gen_client_key()).collect_vec();
853
854 let key_shares = cks
855 .iter()
856 .enumerate()
857 .map(|(user_index, ck)| gen_server_key_share(user_index, parties, ck))
858 .collect_vec();
859
860 let seeded_server_key = aggregate_server_key_shares(&key_shares);
861 seeded_server_key.set_server_key();
862
863 let parameters = BoolEvaluator::with_local(|e| e.parameters().clone());
864 let nttop = NttBackendU64::new(parameters.rlwe_q(), parameters.rlwe_n().0);
865 let rlwe_q_modop = ModularOpsU64::new(*parameters.rlwe_q());
866
867 let m = (0..parameters.rlwe_n().0)
868 .map(|_| thread_rng().gen_bool(0.5))
869 .collect_vec();
870 let ct = cks[0]
871 .encrypt(m.as_slice())
872 .unseed::<Vec<Vec<u64>>>()
873 .key_switch(0);
874 assert!(ct.data().len() == 1);
875
876 let ideal_rlwe_sk = ideal_sk_rlwe(&cks);
877
878 let message = m
879 .iter()
880 .map(|b| parameters.rlwe_q().encode(*b))
881 .collect_vec();
882
883 let mut m_out = vec![0u64; parameters.rlwe_n().0];
884 decrypt_rlwe(
885 &ct.data()[0],
886 &ideal_rlwe_sk,
887 &mut m_out,
888 &nttop,
889 &rlwe_q_modop,
890 );
891
892 let mut diff = m_out;
893 rlwe_q_modop.elwise_sub_mut(diff.as_mut_slice(), message.as_ref());
894
895 let mut stats = Stats::new();
896 stats.add_many_samples(&Vec::<i64>::try_convert_from(
897 diff.as_slice(),
898 parameters.rlwe_q(),
899 ));
900 println!("Noise std log2: {}", stats.std_dev().abs().log2());
901 }
902
903 #[test]
904 fn mod_switch_noise() {
905 // Experiment to check mod switch noise using different secret dist in
906 // multi-party setting
907
908 use itertools::izip;
909 use num_traits::ToPrimitive;
910
911 use crate::{
912 backend::{Modulus, ModulusPowerOf2},
913 parameters::SecretKeyDistribution,
914 random::{DefaultSecureRng, RandomFillGaussian, RandomFillUniformInModulus},
915 utils::{fill_random_ternary_secret_with_hamming_weight, tests::Stats},
916 ArithmeticOps, ModInit,
917 };
918
919 fn mod_switch(v: u64, q_from: u64, q_to: u64) -> f64 {
920 (v as f64) * (q_to as f64) / q_from as f64
921 }
922
923 fn mod_switch_round(v: u64, q_from: u64, q_to: u64) -> u64 {
924 mod_switch(v, q_from, q_to).round().to_u64().unwrap()
925 }
926
927 fn mod_switch_odd(v: u64, q_from: u64, q_to: u64) -> u64 {
928 let odd_v = mod_switch(v, q_from, q_to).floor().to_u64().unwrap();
929 odd_v + ((odd_v & 1) ^ 1)
930 }
931
932 fn sample_secret(n: usize, dist: &SecretKeyDistribution) -> Vec<i32> {
933 let mut s = vec![0i32; n];
934 let mut rng = DefaultSecureRng::new();
935
936 match dist {
937 SecretKeyDistribution::ErrorDistribution => {
938 RandomFillGaussian::random_fill(&mut rng, s.as_mut_slice());
939 }
940 SecretKeyDistribution::TernaryDistribution => {
941 fill_random_ternary_secret_with_hamming_weight(&mut s, n >> 1, &mut rng);
942 }
943 }
944
945 s
946 }
947
948 let parties = 2;
949 let q_from = 1 << 40;
950 let q_to = 1 << 20;
951 let n = 480;
952 let lweq_in_modop = ModulusPowerOf2::new(q_from);
953 let lweq_out_modop = ModulusPowerOf2::new(q_to);
954 let secret_dist = SecretKeyDistribution::ErrorDistribution;
955
956 let mut stats_ms_noise = Stats::new();
957 let mut stats_ms_rounding_err = Stats::new();
958
959 for _ in 0..1000000 {
960 let mut rng = DefaultSecureRng::new();
961
962 // sample secrets
963
964 let s = {
965 let mut s = vec![0i32; n];
966 for _ in 0..parties {
967 let temp = sample_secret(n, &secret_dist);
968 izip!(s.iter_mut(), temp.iter()).for_each(|(si, ti)| {
969 *si = *si + *ti;
970 });
971 }
972 s
973 };
974
975 let m = 10;
976
977 // LWE encryption without noise
978 let mut lwe_in = vec![0u64; n + 1];
979 {
980 RandomFillUniformInModulus::random_fill(&mut rng, &q_from, &mut lwe_in[1..]);
981 let mut b = m;
982 izip!(lwe_in.iter().skip(1), s.iter()).for_each(|(ai, si)| {
983 b = lweq_in_modop.add(
984 &b,
985 &lweq_in_modop.mul(ai, &q_from.map_element_from_i64(*si as i64)),
986 );
987 });
988 lwe_in[0] = b;
989 }
990
991 // Mod switch
992 let lwe_out = lwe_in
993 .iter()
994 .map(|v| {
995 // mod_switch_round(*v, q_from, q_to)
996 mod_switch_odd(*v, q_from, q_to)
997 })
998 .collect_vec();
999
1000 let rounding_errors = izip!(lwe_out.iter(), lwe_in.iter())
1001 .map(|(v_out, v_in)| {
1002 let r_i = mod_switch(*v_in, q_from, q_to) - (*v_out as f64);
1003 r_i
1004 })
1005 .collect_vec();
1006 stats_ms_rounding_err.add_many_samples(&rounding_errors);
1007
1008 // LWE decrypt and calculate ms noise
1009 let mut m_back = 0;
1010 izip!(lwe_out.iter().skip(1), s.iter()).for_each(|(ai, si)| {
1011 m_back = lweq_out_modop.add(
1012 &m_back,
1013 &lweq_out_modop.mul(ai, &q_from.map_element_from_i64(*si as i64)),
1014 );
1015 });
1016 m_back = lweq_out_modop.sub(&lwe_out[0], &m_back);
1017 let noise = lweq_out_modop.sub(&m_back, &m);
1018 stats_ms_noise.add_many_samples(&vec![q_to.map_element_to_i64(&noise)]);
1019 }
1020
1021 println!("ms noise variance: {}", stats_ms_noise.variance());
1022 println!("ms rounding errors mean: {}", stats_ms_rounding_err.mean());
1023 println!(
1024 "ms rounding errors variance: {}",
1025 stats_ms_rounding_err.variance()
1026 );
1027 }
1028}