poulpy/core/src/glwe_ciphertext.rs
core/src/glwe_ciphertext.rsRaw
1use backend::{
2 AddNormal, Backend, FFT64, FillUniform, MatZnxDft, MatZnxDftOps, MatZnxDftScratch, MatZnxDftToRef, Module, ScalarZnxAlloc,
3 ScalarZnxDft, ScalarZnxDftAlloc, ScalarZnxDftOps, ScalarZnxDftToRef, Scratch, VecZnx, VecZnxAlloc, VecZnxBig, VecZnxBigAlloc,
4 VecZnxBigOps, VecZnxBigScratch, VecZnxDft, VecZnxDftAlloc, VecZnxDftOps, VecZnxDftToMut, VecZnxDftToRef, VecZnxOps,
5 VecZnxToMut, VecZnxToRef, ZnxInfos, ZnxZero,
6};
7use sampling::source::Source;
8
9use crate::{
10 SIX_SIGMA,
11 automorphism::AutomorphismKey,
12 elem::{Infos, SetMetaData},
13 ggsw_ciphertext::GGSWCiphertext,
14 glwe_ciphertext_fourier::GLWECiphertextFourier,
15 glwe_plaintext::GLWEPlaintext,
16 keys::{GLWEPublicKey, SecretDistribution, SecretKeyFourier},
17 keyswitch_key::GLWESwitchingKey,
18 utils::derive_size,
19};
20
21pub struct GLWECiphertext<C> {
22 pub data: VecZnx<C>,
23 pub basek: usize,
24 pub k: usize,
25}
26
27impl GLWECiphertext<Vec<u8>> {
28 pub fn alloc<B: Backend>(module: &Module<B>, basek: usize, k: usize, rank: usize) -> Self {
29 Self {
30 data: module.new_vec_znx(rank + 1, derive_size(basek, k)),
31 basek,
32 k,
33 }
34 }
35}
36
37impl<T> Infos for GLWECiphertext<T> {
38 type Inner = VecZnx<T>;
39
40 fn inner(&self) -> &Self::Inner {
41 &self.data
42 }
43
44 fn basek(&self) -> usize {
45 self.basek
46 }
47
48 fn k(&self) -> usize {
49 self.k
50 }
51}
52
53impl<T> GLWECiphertext<T> {
54 pub fn rank(&self) -> usize {
55 self.cols() - 1
56 }
57}
58
59impl<C> VecZnxToMut for GLWECiphertext<C>
60where
61 VecZnx<C>: VecZnxToMut,
62{
63 fn to_mut(&mut self) -> VecZnx<&mut [u8]> {
64 self.data.to_mut()
65 }
66}
67
68impl<C> VecZnxToRef for GLWECiphertext<C>
69where
70 VecZnx<C>: VecZnxToRef,
71{
72 fn to_ref(&self) -> VecZnx<&[u8]> {
73 self.data.to_ref()
74 }
75}
76
77impl<C> GLWECiphertext<C>
78where
79 VecZnx<C>: VecZnxToRef,
80{
81 #[allow(dead_code)]
82 pub(crate) fn dft<R>(&self, module: &Module<FFT64>, res: &mut GLWECiphertextFourier<R, FFT64>)
83 where
84 VecZnxDft<R, FFT64>: VecZnxDftToMut<FFT64> + ZnxInfos,
85 {
86 #[cfg(debug_assertions)]
87 {
88 assert_eq!(self.rank(), res.rank());
89 assert_eq!(self.basek(), res.basek())
90 }
91
92 (0..self.rank() + 1).for_each(|i| {
93 module.vec_znx_dft(res, i, self, i);
94 })
95 }
96}
97
98impl GLWECiphertext<Vec<u8>> {
99 pub fn encrypt_sk_scratch_space(module: &Module<FFT64>, ct_size: usize) -> usize {
100 module.vec_znx_big_normalize_tmp_bytes()
101 + module.bytes_of_vec_znx_dft(1, ct_size)
102 + module.bytes_of_vec_znx_big(1, ct_size)
103 }
104 pub fn encrypt_pk_scratch_space(module: &Module<FFT64>, pk_size: usize) -> usize {
105 ((module.bytes_of_vec_znx_dft(1, pk_size) + module.bytes_of_vec_znx_big(1, pk_size)) | module.bytes_of_scalar_znx(1))
106 + module.bytes_of_scalar_znx_dft(1)
107 + module.vec_znx_big_normalize_tmp_bytes()
108 }
109
110 pub fn decrypt_scratch_space(module: &Module<FFT64>, ct_size: usize) -> usize {
111 (module.vec_znx_big_normalize_tmp_bytes() | module.bytes_of_vec_znx_dft(1, ct_size))
112 + module.bytes_of_vec_znx_big(1, ct_size)
113 }
114
115 pub fn keyswitch_scratch_space(
116 module: &Module<FFT64>,
117 out_size: usize,
118 out_rank: usize,
119 in_size: usize,
120 in_rank: usize,
121 ksk_size: usize,
122 ) -> usize {
123 let res_dft: usize = module.bytes_of_vec_znx_dft(out_rank + 1, ksk_size);
124 let vmp: usize = module.vmp_apply_tmp_bytes(out_size, in_size, in_size, in_rank, out_rank + 1, ksk_size)
125 + module.bytes_of_vec_znx_dft(in_rank, in_size);
126 let normalize: usize = module.vec_znx_big_normalize_tmp_bytes();
127
128 return res_dft + (vmp | normalize);
129 }
130
131 pub fn keyswitch_from_fourier_scratch_space(
132 module: &Module<FFT64>,
133 out_size: usize,
134 out_rank: usize,
135 in_size: usize,
136 in_rank: usize,
137 ksk_size: usize,
138 ) -> usize {
139 let res_dft = module.bytes_of_vec_znx_dft(out_rank + 1, ksk_size);
140
141 let vmp: usize = module.vmp_apply_tmp_bytes(out_size, in_size, in_size, in_rank, out_rank + 1, ksk_size)
142 + module.bytes_of_vec_znx_dft(in_rank, in_size);
143
144 let norm: usize = module.vec_znx_big_normalize_tmp_bytes();
145
146 res_dft + (vmp | norm)
147 }
148
149 pub fn keyswitch_inplace_scratch_space(module: &Module<FFT64>, out_size: usize, out_rank: usize, ksk_size: usize) -> usize {
150 GLWECiphertext::keyswitch_scratch_space(module, out_size, out_rank, out_size, out_rank, ksk_size)
151 }
152
153 pub fn automorphism_scratch_space(
154 module: &Module<FFT64>,
155 out_size: usize,
156 out_rank: usize,
157 in_size: usize,
158 autokey_size: usize,
159 ) -> usize {
160 GLWECiphertext::keyswitch_scratch_space(module, out_size, out_rank, in_size, out_rank, autokey_size)
161 }
162
163 pub fn automorphism_inplace_scratch_space(
164 module: &Module<FFT64>,
165 out_size: usize,
166 out_rank: usize,
167 autokey_size: usize,
168 ) -> usize {
169 GLWECiphertext::keyswitch_scratch_space(module, out_size, out_rank, out_size, out_rank, autokey_size)
170 }
171
172 pub fn external_product_scratch_space(
173 module: &Module<FFT64>,
174 out_size: usize,
175 out_rank: usize,
176 in_size: usize,
177 ggsw_size: usize,
178 ) -> usize {
179 let res_dft: usize = module.bytes_of_vec_znx_dft(out_rank + 1, ggsw_size);
180 let vmp: usize = module.bytes_of_vec_znx_dft(out_rank + 1, in_size)
181 + module.vmp_apply_tmp_bytes(
182 out_size,
183 in_size,
184 in_size, // rows
185 out_rank + 1, // cols in
186 out_rank + 1, // cols out
187 ggsw_size,
188 );
189 let normalize: usize = module.vec_znx_big_normalize_tmp_bytes();
190
191 res_dft + (vmp | normalize)
192 }
193
194 pub fn external_product_inplace_scratch_space(
195 module: &Module<FFT64>,
196 out_size: usize,
197 out_rank: usize,
198 ggsw_size: usize,
199 ) -> usize {
200 GLWECiphertext::external_product_scratch_space(module, out_size, out_rank, out_size, ggsw_size)
201 }
202}
203
204impl<DataSelf> SetMetaData for GLWECiphertext<DataSelf>
205where
206 VecZnx<DataSelf>: VecZnxToMut,
207{
208 fn set_k(&mut self, k: usize) {
209 self.k = k
210 }
211
212 fn set_basek(&mut self, basek: usize) {
213 self.basek = basek
214 }
215}
216
217impl<DataSelf> GLWECiphertext<DataSelf>
218where
219 VecZnx<DataSelf>: VecZnxToMut,
220{
221 pub fn encrypt_sk<DataPt, DataSk>(
222 &mut self,
223 module: &Module<FFT64>,
224 pt: &GLWEPlaintext<DataPt>,
225 sk_dft: &SecretKeyFourier<DataSk, FFT64>,
226 source_xa: &mut Source,
227 source_xe: &mut Source,
228 sigma: f64,
229 scratch: &mut Scratch,
230 ) where
231 VecZnx<DataPt>: VecZnxToRef,
232 ScalarZnxDft<DataSk, FFT64>: ScalarZnxDftToRef<FFT64>,
233 {
234 self.encrypt_sk_private(
235 module,
236 Some((pt, 0)),
237 sk_dft,
238 source_xa,
239 source_xe,
240 sigma,
241 scratch,
242 );
243 }
244
245 pub fn encrypt_zero_sk<DataSk>(
246 &mut self,
247 module: &Module<FFT64>,
248 sk_dft: &SecretKeyFourier<DataSk, FFT64>,
249 source_xa: &mut Source,
250 source_xe: &mut Source,
251 sigma: f64,
252 scratch: &mut Scratch,
253 ) where
254 ScalarZnxDft<DataSk, FFT64>: ScalarZnxDftToRef<FFT64>,
255 {
256 self.encrypt_sk_private(module, None, sk_dft, source_xa, source_xe, sigma, scratch);
257 }
258
259 pub fn encrypt_pk<DataPt, DataPk>(
260 &mut self,
261 module: &Module<FFT64>,
262 pt: &GLWEPlaintext<DataPt>,
263 pk: &GLWEPublicKey<DataPk, FFT64>,
264 source_xu: &mut Source,
265 source_xe: &mut Source,
266 sigma: f64,
267 scratch: &mut Scratch,
268 ) where
269 VecZnx<DataPt>: VecZnxToRef,
270 VecZnxDft<DataPk, FFT64>: VecZnxDftToRef<FFT64>,
271 {
272 self.encrypt_pk_private(
273 module,
274 Some((pt, 0)),
275 pk,
276 source_xu,
277 source_xe,
278 sigma,
279 scratch,
280 );
281 }
282
283 pub fn encrypt_zero_pk<DataPk>(
284 &mut self,
285 module: &Module<FFT64>,
286 pk: &GLWEPublicKey<DataPk, FFT64>,
287 source_xu: &mut Source,
288 source_xe: &mut Source,
289 sigma: f64,
290 scratch: &mut Scratch,
291 ) where
292 VecZnxDft<DataPk, FFT64>: VecZnxDftToRef<FFT64>,
293 {
294 self.encrypt_pk_private(module, None, pk, source_xu, source_xe, sigma, scratch);
295 }
296
297 pub fn automorphism<DataLhs, DataRhs>(
298 &mut self,
299 module: &Module<FFT64>,
300 lhs: &GLWECiphertext<DataLhs>,
301 rhs: &AutomorphismKey<DataRhs, FFT64>,
302 scratch: &mut Scratch,
303 ) where
304 VecZnx<DataLhs>: VecZnxToRef,
305 MatZnxDft<DataRhs, FFT64>: MatZnxDftToRef<FFT64>,
306 {
307 self.keyswitch(module, lhs, &rhs.key, scratch);
308 (0..self.rank() + 1).for_each(|i| {
309 module.vec_znx_automorphism_inplace(rhs.p(), self, i);
310 })
311 }
312
313 pub fn automorphism_inplace<DataRhs>(
314 &mut self,
315 module: &Module<FFT64>,
316 rhs: &AutomorphismKey<DataRhs, FFT64>,
317 scratch: &mut Scratch,
318 ) where
319 MatZnxDft<DataRhs, FFT64>: MatZnxDftToRef<FFT64>,
320 {
321 self.keyswitch_inplace(module, &rhs.key, scratch);
322 (0..self.rank() + 1).for_each(|i| {
323 module.vec_znx_automorphism_inplace(rhs.p(), self, i);
324 })
325 }
326
327 pub fn automorphism_add<DataLhs, DataRhs>(
328 &mut self,
329 module: &Module<FFT64>,
330 lhs: &GLWECiphertext<DataLhs>,
331 rhs: &AutomorphismKey<DataRhs, FFT64>,
332 scratch: &mut Scratch,
333 ) where
334 VecZnx<DataLhs>: VecZnxToRef,
335 MatZnxDft<DataRhs, FFT64>: MatZnxDftToRef<FFT64>,
336 {
337 Self::keyswitch_private(self, true, rhs.p(), module, lhs, &rhs.key, scratch);
338 }
339
340 pub fn automorphism_add_inplace<DataRhs>(
341 &mut self,
342 module: &Module<FFT64>,
343 rhs: &AutomorphismKey<DataRhs, FFT64>,
344 scratch: &mut Scratch,
345 ) where
346 MatZnxDft<DataRhs, FFT64>: MatZnxDftToRef<FFT64>,
347 {
348 unsafe {
349 let self_ptr: *mut GLWECiphertext<DataSelf> = self as *mut GLWECiphertext<DataSelf>;
350 Self::keyswitch_private(self, true, rhs.p(), module, &*self_ptr, &rhs.key, scratch);
351 }
352 }
353
354 pub(crate) fn keyswitch_from_fourier<DataLhs, DataRhs>(
355 &mut self,
356 module: &Module<FFT64>,
357 lhs: &GLWECiphertextFourier<DataLhs, FFT64>,
358 rhs: &GLWESwitchingKey<DataRhs, FFT64>,
359 scratch: &mut Scratch,
360 ) where
361 VecZnxDft<DataLhs, FFT64>: VecZnxDftToRef<FFT64>,
362 MatZnxDft<DataRhs, FFT64>: MatZnxDftToRef<FFT64>,
363 {
364 let basek: usize = self.basek();
365
366 #[cfg(debug_assertions)]
367 {
368 assert_eq!(lhs.rank(), rhs.rank_in());
369 assert_eq!(self.rank(), rhs.rank_out());
370 assert_eq!(self.basek(), basek);
371 assert_eq!(lhs.basek(), basek);
372 assert_eq!(rhs.n(), module.n());
373 assert_eq!(self.n(), module.n());
374 assert_eq!(lhs.n(), module.n());
375 assert!(
376 scratch.available()
377 >= GLWECiphertext::keyswitch_from_fourier_scratch_space(
378 module,
379 self.size(),
380 self.rank(),
381 lhs.size(),
382 lhs.rank(),
383 rhs.size(),
384 )
385 );
386 }
387
388 let cols_in: usize = rhs.rank_in();
389 let cols_out: usize = rhs.rank_out() + 1;
390
391 // Buffer of the result of VMP in DFT
392 let (mut res_dft, scratch1) = scratch.tmp_vec_znx_dft(module, cols_out, rhs.size()); // Todo optimise
393
394 {
395 // Applies VMP
396 let (mut ai_dft, scratch2) = scratch1.tmp_vec_znx_dft(module, cols_in, lhs.size());
397 (0..cols_in).for_each(|col_i| {
398 module.vec_znx_dft_copy(&mut ai_dft, col_i, lhs, col_i + 1);
399 });
400 module.vmp_apply(&mut res_dft, &ai_dft, rhs, scratch2);
401 }
402
403 module.vec_znx_dft_add_inplace(&mut res_dft, 0, lhs, 0);
404
405 // Switches result of VMP outside of DFT
406 let res_big: VecZnxBig<&mut [u8], FFT64> = module.vec_znx_idft_consume::<&mut [u8]>(res_dft);
407
408 (0..cols_out).for_each(|i| {
409 module.vec_znx_big_normalize(basek, self, i, &res_big, i, scratch1);
410 });
411 }
412
413 pub fn keyswitch<DataLhs, DataRhs>(
414 &mut self,
415 module: &Module<FFT64>,
416 lhs: &GLWECiphertext<DataLhs>,
417 rhs: &GLWESwitchingKey<DataRhs, FFT64>,
418 scratch: &mut Scratch,
419 ) where
420 VecZnx<DataLhs>: VecZnxToRef,
421 MatZnxDft<DataRhs, FFT64>: MatZnxDftToRef<FFT64>,
422 {
423 Self::keyswitch_private(self, false, 0, module, lhs, rhs, scratch);
424 }
425
426 pub(crate) fn keyswitch_private<DataLhs, DataRhs>(
427 &mut self,
428 add_self: bool,
429 apply_auto: i64,
430 module: &Module<FFT64>,
431 lhs: &GLWECiphertext<DataLhs>,
432 rhs: &GLWESwitchingKey<DataRhs, FFT64>,
433 scratch: &mut Scratch,
434 ) where
435 VecZnx<DataLhs>: VecZnxToRef,
436 MatZnxDft<DataRhs, FFT64>: MatZnxDftToRef<FFT64>,
437 {
438 let basek: usize = self.basek();
439
440 #[cfg(debug_assertions)]
441 {
442 assert_eq!(lhs.rank(), rhs.rank_in());
443 assert_eq!(self.rank(), rhs.rank_out());
444 assert_eq!(self.basek(), basek);
445 assert_eq!(lhs.basek(), basek);
446 assert_eq!(rhs.n(), module.n());
447 assert_eq!(self.n(), module.n());
448 assert_eq!(lhs.n(), module.n());
449 assert!(
450 scratch.available()
451 >= GLWECiphertext::keyswitch_scratch_space(
452 module,
453 self.size(),
454 self.rank(),
455 lhs.size(),
456 lhs.rank(),
457 rhs.size(),
458 )
459 );
460 }
461
462 let cols_in: usize = rhs.rank_in();
463 let cols_out: usize = rhs.rank_out() + 1;
464
465 let (mut res_dft, scratch1) = scratch.tmp_vec_znx_dft(module, cols_out, rhs.size()); // Todo optimise
466
467 {
468 let (mut ai_dft, scratch2) = scratch1.tmp_vec_znx_dft(module, cols_in, lhs.size());
469 (0..cols_in).for_each(|col_i| {
470 module.vec_znx_dft(&mut ai_dft, col_i, lhs, col_i + 1);
471 });
472 module.vmp_apply(&mut res_dft, &ai_dft, rhs, scratch2);
473 }
474
475 let mut res_big: VecZnxBig<&mut [u8], FFT64> = module.vec_znx_idft_consume(res_dft);
476
477 module.vec_znx_big_add_small_inplace(&mut res_big, 0, lhs, 0);
478
479 (0..cols_out).for_each(|i| {
480 if apply_auto != 0 {
481 module.vec_znx_big_automorphism_inplace(apply_auto, &mut res_big, i);
482 }
483
484 if add_self {
485 module.vec_znx_big_add_small_inplace(&mut res_big, i, lhs, i);
486 }
487 module.vec_znx_big_normalize(basek, self, i, &res_big, i, scratch1);
488 });
489 }
490
491 pub fn keyswitch_inplace<DataRhs>(
492 &mut self,
493 module: &Module<FFT64>,
494 rhs: &GLWESwitchingKey<DataRhs, FFT64>,
495 scratch: &mut Scratch,
496 ) where
497 MatZnxDft<DataRhs, FFT64>: MatZnxDftToRef<FFT64>,
498 {
499 unsafe {
500 let self_ptr: *mut GLWECiphertext<DataSelf> = self as *mut GLWECiphertext<DataSelf>;
501 self.keyswitch(&module, &*self_ptr, rhs, scratch);
502 }
503 }
504
505 pub fn external_product<DataLhs, DataRhs>(
506 &mut self,
507 module: &Module<FFT64>,
508 lhs: &GLWECiphertext<DataLhs>,
509 rhs: &GGSWCiphertext<DataRhs, FFT64>,
510 scratch: &mut Scratch,
511 ) where
512 VecZnx<DataLhs>: VecZnxToRef,
513 MatZnxDft<DataRhs, FFT64>: MatZnxDftToRef<FFT64>,
514 {
515 let basek: usize = self.basek();
516
517 #[cfg(debug_assertions)]
518 {
519 assert_eq!(rhs.rank(), lhs.rank());
520 assert_eq!(rhs.rank(), self.rank());
521 assert_eq!(self.basek(), basek);
522 assert_eq!(lhs.basek(), basek);
523 assert_eq!(rhs.n(), module.n());
524 assert_eq!(self.n(), module.n());
525 assert_eq!(lhs.n(), module.n());
526 }
527
528 let cols: usize = rhs.rank() + 1;
529
530 let (mut res_dft, scratch1) = scratch.tmp_vec_znx_dft(module, cols, rhs.size()); // Todo optimise
531
532 {
533 let (mut a_dft, scratch2) = scratch1.tmp_vec_znx_dft(module, cols, lhs.size());
534 (0..cols).for_each(|col_i| {
535 module.vec_znx_dft(&mut a_dft, col_i, lhs, col_i);
536 });
537 module.vmp_apply(&mut res_dft, &a_dft, rhs, scratch2);
538 }
539
540 let res_big: VecZnxBig<&mut [u8], FFT64> = module.vec_znx_idft_consume(res_dft);
541
542 (0..cols).for_each(|i| {
543 module.vec_znx_big_normalize(basek, self, i, &res_big, i, scratch1);
544 });
545 }
546
547 pub fn external_product_inplace<DataRhs>(
548 &mut self,
549 module: &Module<FFT64>,
550 rhs: &GGSWCiphertext<DataRhs, FFT64>,
551 scratch: &mut Scratch,
552 ) where
553 MatZnxDft<DataRhs, FFT64>: MatZnxDftToRef<FFT64>,
554 {
555 unsafe {
556 let self_ptr: *mut GLWECiphertext<DataSelf> = self as *mut GLWECiphertext<DataSelf>;
557 self.external_product(&module, &*self_ptr, rhs, scratch);
558 }
559 }
560
561 pub(crate) fn encrypt_sk_private<DataPt, DataSk>(
562 &mut self,
563 module: &Module<FFT64>,
564 pt: Option<(&GLWEPlaintext<DataPt>, usize)>,
565 sk_dft: &SecretKeyFourier<DataSk, FFT64>,
566 source_xa: &mut Source,
567 source_xe: &mut Source,
568 sigma: f64,
569 scratch: &mut Scratch,
570 ) where
571 VecZnx<DataPt>: VecZnxToRef,
572 ScalarZnxDft<DataSk, FFT64>: ScalarZnxDftToRef<FFT64>,
573 {
574 #[cfg(debug_assertions)]
575 {
576 assert_eq!(self.rank(), sk_dft.rank());
577 assert_eq!(sk_dft.n(), module.n());
578 assert_eq!(self.n(), module.n());
579 if let Some((pt, col)) = pt {
580 assert_eq!(pt.n(), module.n());
581 assert!(col < self.rank() + 1);
582 }
583 }
584
585 let basek: usize = self.basek();
586 let k: usize = self.k();
587 let size: usize = self.size();
588 let cols: usize = self.rank() + 1;
589
590 let (mut c0_big, scratch_1) = scratch.tmp_vec_znx(module, 1, size);
591 c0_big.zero();
592
593 {
594 // c[i] = uniform
595 // c[0] -= c[i] * s[i],
596 (1..cols).for_each(|i| {
597 let (mut ci_dft, scratch_2) = scratch_1.tmp_vec_znx_dft(module, 1, size);
598
599 // c[i] = uniform
600 self.data.fill_uniform(basek, i, size, source_xa);
601
602 // c[i] = norm(IDFT(DFT(c[i]) * DFT(s[i])))
603 module.vec_znx_dft(&mut ci_dft, 0, self, i);
604 module.svp_apply_inplace(&mut ci_dft, 0, sk_dft, i - 1);
605 let ci_big: VecZnxBig<&mut [u8], FFT64> = module.vec_znx_idft_consume(ci_dft);
606
607 // use c[0] as buffer, which is overwritten later by the normalization step
608 module.vec_znx_big_normalize(basek, self, 0, &ci_big, 0, scratch_2);
609
610 // c0_tmp = -c[i] * s[i] (use c[0] as buffer)
611 module.vec_znx_sub_ab_inplace(&mut c0_big, 0, self, 0);
612
613 // c[i] += m if col = i
614 if let Some((pt, col)) = pt {
615 if i == col {
616 module.vec_znx_add_inplace(self, i, pt, 0);
617 module.vec_znx_normalize_inplace(basek, self, i, scratch_2);
618 }
619 }
620 });
621 }
622
623 // c[0] += e
624 c0_big.add_normal(basek, 0, k, source_xe, sigma, sigma * SIX_SIGMA);
625
626 // c[0] += m if col = 0
627 if let Some((pt, col)) = pt {
628 if col == 0 {
629 module.vec_znx_add_inplace(&mut c0_big, 0, pt, 0);
630 }
631 }
632
633 // c[0] = norm(c[0])
634 module.vec_znx_normalize(basek, self, 0, &c0_big, 0, scratch_1);
635 }
636
637 pub(crate) fn encrypt_pk_private<DataPt, DataPk>(
638 &mut self,
639 module: &Module<FFT64>,
640 pt: Option<(&GLWEPlaintext<DataPt>, usize)>,
641 pk: &GLWEPublicKey<DataPk, FFT64>,
642 source_xu: &mut Source,
643 source_xe: &mut Source,
644 sigma: f64,
645 scratch: &mut Scratch,
646 ) where
647 VecZnx<DataPt>: VecZnxToRef,
648 VecZnxDft<DataPk, FFT64>: VecZnxDftToRef<FFT64>,
649 {
650 #[cfg(debug_assertions)]
651 {
652 assert_eq!(self.basek(), pk.basek());
653 assert_eq!(self.n(), module.n());
654 assert_eq!(pk.n(), module.n());
655 assert_eq!(self.rank(), pk.rank());
656 if let Some((pt, _)) = pt {
657 assert_eq!(pt.basek(), pk.basek());
658 assert_eq!(pt.n(), module.n());
659 }
660 }
661
662 let basek: usize = pk.basek();
663 let size_pk: usize = pk.size();
664 let cols: usize = self.rank() + 1;
665
666 // Generates u according to the underlying secret distribution.
667 let (mut u_dft, scratch_1) = scratch.tmp_scalar_znx_dft(module, 1);
668
669 {
670 let (mut u, _) = scratch_1.tmp_scalar_znx(module, 1);
671 match pk.dist {
672 SecretDistribution::NONE => panic!(
673 "invalid public key: SecretDistribution::NONE, ensure it has been correctly intialized through \
674 Self::generate"
675 ),
676 SecretDistribution::TernaryFixed(hw) => u.fill_ternary_hw(0, hw, source_xu),
677 SecretDistribution::TernaryProb(prob) => u.fill_ternary_prob(0, prob, source_xu),
678 SecretDistribution::ZERO => {}
679 }
680
681 module.svp_prepare(&mut u_dft, 0, &u, 0);
682 }
683
684 // ct[i] = pk[i] * u + ei (+ m if col = i)
685 (0..cols).for_each(|i| {
686 let (mut ci_dft, scratch_2) = scratch_1.tmp_vec_znx_dft(module, 1, size_pk);
687 // ci_dft = DFT(u) * DFT(pk[i])
688 module.svp_apply(&mut ci_dft, 0, &u_dft, 0, pk, i);
689
690 // ci_big = u * p[i]
691 let mut ci_big = module.vec_znx_idft_consume(ci_dft);
692
693 // ci_big = u * pk[i] + e
694 ci_big.add_normal(basek, 0, pk.k(), source_xe, sigma, sigma * SIX_SIGMA);
695
696 // ci_big = u * pk[i] + e + m (if col = i)
697 if let Some((pt, col)) = pt {
698 if col == i {
699 module.vec_znx_big_add_small_inplace(&mut ci_big, 0, pt, 0);
700 }
701 }
702
703 // ct[i] = norm(ci_big)
704 module.vec_znx_big_normalize(basek, self, i, &ci_big, 0, scratch_2);
705 });
706 }
707}
708
709impl<DataSelf> GLWECiphertext<DataSelf>
710where
711 VecZnx<DataSelf>: VecZnxToRef,
712{
713 pub fn clone(&self) -> GLWECiphertext<Vec<u8>> {
714 GLWECiphertext {
715 data: self.data.clone(),
716 basek: self.basek(),
717 k: self.k(),
718 }
719 }
720
721 pub fn decrypt<DataPt, DataSk>(
722 &self,
723 module: &Module<FFT64>,
724 pt: &mut GLWEPlaintext<DataPt>,
725 sk_dft: &SecretKeyFourier<DataSk, FFT64>,
726 scratch: &mut Scratch,
727 ) where
728 VecZnx<DataPt>: VecZnxToMut,
729 ScalarZnxDft<DataSk, FFT64>: ScalarZnxDftToRef<FFT64>,
730 {
731 #[cfg(debug_assertions)]
732 {
733 assert_eq!(self.rank(), sk_dft.rank());
734 assert_eq!(self.n(), module.n());
735 assert_eq!(pt.n(), module.n());
736 assert_eq!(sk_dft.n(), module.n());
737 }
738
739 let cols: usize = self.rank() + 1;
740
741 let (mut c0_big, scratch_1) = scratch.tmp_vec_znx_big(module, 1, self.size()); // TODO optimize size when pt << ct
742 c0_big.zero();
743
744 {
745 (1..cols).for_each(|i| {
746 // ci_dft = DFT(a[i]) * DFT(s[i])
747 let (mut ci_dft, _) = scratch_1.tmp_vec_znx_dft(module, 1, self.size()); // TODO optimize size when pt << ct
748 module.vec_znx_dft(&mut ci_dft, 0, self, i);
749 module.svp_apply_inplace(&mut ci_dft, 0, sk_dft, i - 1);
750 let ci_big = module.vec_znx_idft_consume(ci_dft);
751
752 // c0_big += a[i] * s[i]
753 module.vec_znx_big_add_inplace(&mut c0_big, 0, &ci_big, 0);
754 });
755 }
756
757 // c0_big = (a * s) + (-a * s + m + e) = BIG(m + e)
758 module.vec_znx_big_add_small_inplace(&mut c0_big, 0, self, 0);
759
760 // pt = norm(BIG(m + e))
761 module.vec_znx_big_normalize(self.basek(), pt, 0, &mut c0_big, 0, scratch_1);
762
763 pt.basek = self.basek();
764 pt.k = pt.k().min(self.k());
765 }
766}