phantom-zone/src/shortint/mod.rs
src/shortint/mod.rsRaw
1use itertools::Itertools;
2
3use crate::{
4 bool::keys::{ClientKey, PublicKey},
5 Decryptor, Encryptor, MultiPartyDecryptor,
6};
7
8mod ops;
9mod types;
10
11pub type FheUint8 = types::FheUint8<Vec<u64>>;
12
13impl Encryptor<u8, FheUint8> for ClientKey {
14 fn encrypt(&self, m: &u8) -> FheUint8 {
15 let cts = (0..8)
16 .into_iter()
17 .map(|i| {
18 let bit = ((m >> i) & 1) == 1;
19 Encryptor::<bool, Vec<u64>>::encrypt(self, &bit)
20 })
21 .collect_vec();
22 FheUint8 { data: cts }
23 }
24}
25
26impl Decryptor<u8, FheUint8> for ClientKey {
27 fn decrypt(&self, c: &FheUint8) -> u8 {
28 assert!(c.data.len() == 8);
29 let mut out = 0u8;
30 c.data().iter().enumerate().for_each(|(index, bit_c)| {
31 let bool = Decryptor::<bool, Vec<u64>>::decrypt(self, bit_c);
32 if bool {
33 out += 1 << index;
34 }
35 });
36 out
37 }
38}
39
40impl<M, R, Mo> Encryptor<u8, FheUint8> for PublicKey<M, R, Mo>
41where
42 PublicKey<M, R, Mo>: Encryptor<bool, Vec<u64>>,
43{
44 fn encrypt(&self, m: &u8) -> FheUint8 {
45 let cts = (0..8)
46 .into_iter()
47 .map(|i| {
48 let bit = ((m >> i) & 1) == 1;
49 Encryptor::<bool, Vec<u64>>::encrypt(self, &bit)
50 })
51 .collect_vec();
52 FheUint8 { data: cts }
53 }
54}
55
56impl MultiPartyDecryptor<u8, FheUint8> for ClientKey
57where
58 ClientKey: MultiPartyDecryptor<bool, Vec<u64>>,
59{
60 type DecryptionShare = Vec<<Self as MultiPartyDecryptor<bool, Vec<u64>>>::DecryptionShare>;
61 fn gen_decryption_share(&self, c: &FheUint8) -> Self::DecryptionShare {
62 assert!(c.data().len() == 8);
63 c.data()
64 .iter()
65 .map(|bit_c| {
66 let decryption_share =
67 MultiPartyDecryptor::<bool, Vec<u64>>::gen_decryption_share(self, bit_c);
68 decryption_share
69 })
70 .collect_vec()
71 }
72
73 fn aggregate_decryption_shares(&self, c: &FheUint8, shares: &[Self::DecryptionShare]) -> u8 {
74 let mut out = 0u8;
75
76 (0..8).into_iter().for_each(|i| {
77 // Collect bit i^th decryption share of each party
78 let bit_i_decryption_shares = shares.iter().map(|s| s[i]).collect_vec();
79 let bit_i = MultiPartyDecryptor::<bool, Vec<u64>>::aggregate_decryption_shares(
80 self,
81 &c.data()[i],
82 &bit_i_decryption_shares,
83 );
84
85 if bit_i {
86 out += 1 << i;
87 }
88 });
89
90 out
91 }
92}
93
94mod frontend {
95 use super::ops::{
96 arbitrary_bit_adder, arbitrary_bit_division_for_quotient_and_rem, arbitrary_bit_subtractor,
97 eight_bit_mul,
98 };
99 use crate::{
100 bool::{
101 evaluator::{self, BoolEvaluator, BooleanGates},
102 keys::{ServerKeyEvaluationDomain, ShoupServerKeyEvaluationDomain},
103 },
104 utils::{Global, WithLocal},
105 };
106
107 use super::FheUint8;
108
109 mod arithetic {
110 use crate::bool::{FheBool, RuntimeServerKey};
111
112 use super::*;
113 use std::ops::{Add, AddAssign, Div, Mul, Rem, Sub};
114
115 impl AddAssign<&FheUint8> for FheUint8 {
116 fn add_assign(&mut self, rhs: &FheUint8) {
117 BoolEvaluator::with_local_mut_mut(&mut |e| {
118 let key = RuntimeServerKey::global();
119 arbitrary_bit_adder(e, self.data_mut(), rhs.data(), false, key);
120 });
121 }
122 }
123
124 impl Add<&FheUint8> for &FheUint8 {
125 type Output = FheUint8;
126 fn add(self, rhs: &FheUint8) -> Self::Output {
127 let mut a = self.clone();
128 a += rhs;
129 a
130 }
131 }
132
133 impl Sub<&FheUint8> for &FheUint8 {
134 type Output = FheUint8;
135 fn sub(self, rhs: &FheUint8) -> Self::Output {
136 BoolEvaluator::with_local_mut(|e| {
137 let key = RuntimeServerKey::global();
138 let (out, _, _) = arbitrary_bit_subtractor(e, self.data(), rhs.data(), key);
139 FheUint8 { data: out }
140 })
141 }
142 }
143
144 impl Mul<&FheUint8> for &FheUint8 {
145 type Output = FheUint8;
146 fn mul(self, rhs: &FheUint8) -> Self::Output {
147 BoolEvaluator::with_local_mut(|e| {
148 let key = RuntimeServerKey::global();
149 let out = eight_bit_mul(e, self.data(), rhs.data(), key);
150 FheUint8 { data: out }
151 })
152 }
153 }
154
155 impl Div<&FheUint8> for &FheUint8 {
156 type Output = FheUint8;
157 fn div(self, rhs: &FheUint8) -> Self::Output {
158 // TODO(Jay:) Figure out how to set zero error flag
159 BoolEvaluator::with_local_mut(|e| {
160 let key = RuntimeServerKey::global();
161 let (quotient, _) = arbitrary_bit_division_for_quotient_and_rem(
162 e,
163 self.data(),
164 rhs.data(),
165 key,
166 );
167 FheUint8 { data: quotient }
168 })
169 }
170 }
171
172 impl Rem<&FheUint8> for &FheUint8 {
173 type Output = FheUint8;
174 fn rem(self, rhs: &FheUint8) -> Self::Output {
175 BoolEvaluator::with_local_mut(|e| {
176 let key = RuntimeServerKey::global();
177 let (_, remainder) = arbitrary_bit_division_for_quotient_and_rem(
178 e,
179 self.data(),
180 rhs.data(),
181 key,
182 );
183 FheUint8 { data: remainder }
184 })
185 }
186 }
187
188 impl FheUint8 {
189 pub fn overflowing_add_assign(&mut self, rhs: &FheUint8) -> FheBool {
190 BoolEvaluator::with_local_mut_mut(&mut |e| {
191 let key = RuntimeServerKey::global();
192 let (overflow, _) =
193 arbitrary_bit_adder(e, self.data_mut(), rhs.data(), false, key);
194 overflow
195 })
196 }
197
198 pub fn overflowing_add(self, rhs: &FheUint8) -> (FheUint8, FheBool) {
199 BoolEvaluator::with_local_mut(|e| {
200 let mut lhs = self.clone();
201 let key = RuntimeServerKey::global();
202 let (overflow, _) =
203 arbitrary_bit_adder(e, lhs.data_mut(), rhs.data(), false, key);
204 (lhs, overflow)
205 })
206 }
207
208 pub fn overflowing_sub(&self, rhs: &FheUint8) -> (FheUint8, FheBool) {
209 BoolEvaluator::with_local_mut(|e| {
210 let key = RuntimeServerKey::global();
211 let (out, mut overflow, _) =
212 arbitrary_bit_subtractor(e, self.data(), rhs.data(), key);
213 e.not_inplace(&mut overflow);
214 (FheUint8 { data: out }, overflow)
215 })
216 }
217
218 pub fn div_rem(&self, rhs: &FheUint8) -> (FheUint8, FheUint8) {
219 // TODO(Jay:) Figure out how to set zero error flag
220 BoolEvaluator::with_local_mut(|e| {
221 let key = RuntimeServerKey::global();
222 let (quotient, remainder) = arbitrary_bit_division_for_quotient_and_rem(
223 e,
224 self.data(),
225 rhs.data(),
226 key,
227 );
228 (FheUint8 { data: quotient }, FheUint8 { data: remainder })
229 })
230 }
231 }
232 }
233
234 mod booleans {
235 use crate::{
236 bool::{evaluator::BooleanGates, FheBool, RuntimeServerKey},
237 shortint::ops::{
238 arbitrary_bit_comparator, arbitrary_bit_equality, arbitrary_signed_bit_comparator,
239 },
240 };
241
242 use super::*;
243
244 impl FheUint8 {
245 /// a == b
246 pub fn eq(&self, other: &FheUint8) -> FheBool {
247 BoolEvaluator::with_local_mut(|e| {
248 let key = RuntimeServerKey::global();
249 arbitrary_bit_equality(e, self.data(), other.data(), key)
250 })
251 }
252
253 /// a != b
254 pub fn neq(&self, other: &FheUint8) -> FheBool {
255 BoolEvaluator::with_local_mut(|e| {
256 let key = RuntimeServerKey::global();
257 let mut is_equal = arbitrary_bit_equality(e, self.data(), other.data(), key);
258 e.not_inplace(&mut is_equal);
259 is_equal
260 })
261 }
262
263 /// a < b
264 pub fn lt(&self, other: &FheUint8) -> FheBool {
265 BoolEvaluator::with_local_mut(|e| {
266 let key = RuntimeServerKey::global();
267 arbitrary_bit_comparator(e, other.data(), self.data(), key)
268 })
269 }
270
271 /// a > b
272 pub fn gt(&self, other: &FheUint8) -> FheBool {
273 BoolEvaluator::with_local_mut(|e| {
274 let key = RuntimeServerKey::global();
275 arbitrary_bit_comparator(e, self.data(), other.data(), key)
276 })
277 }
278
279 /// a <= b
280 pub fn le(&self, other: &FheUint8) -> FheBool {
281 BoolEvaluator::with_local_mut(|e| {
282 let key = RuntimeServerKey::global();
283 let mut a_greater_b =
284 arbitrary_bit_comparator(e, self.data(), other.data(), key);
285 e.not_inplace(&mut a_greater_b);
286 a_greater_b
287 })
288 }
289
290 /// a >= b
291 pub fn ge(&self, other: &FheUint8) -> FheBool {
292 BoolEvaluator::with_local_mut(|e| {
293 let key = RuntimeServerKey::global();
294 let mut a_less_b = arbitrary_bit_comparator(e, other.data(), self.data(), key);
295 e.not_inplace(&mut a_less_b);
296 a_less_b
297 })
298 }
299 }
300 }
301}
302
303#[cfg(test)]
304mod tests {
305 use itertools::Itertools;
306 use num_traits::Euclid;
307
308 use crate::{
309 bool::{
310 aggregate_public_key_shares, aggregate_server_key_shares, gen_client_key, gen_keys,
311 gen_mp_keys_phase1, gen_mp_keys_phase2, set_mp_seed, set_parameter_set,
312 },
313 shortint::types::FheUint8,
314 Decryptor, Encryptor, MultiPartyDecryptor,
315 };
316
317 #[test]
318 fn all_uint8_apis() {
319 set_parameter_set(crate::ParameterSelector::MultiPartyLessThan16);
320
321 let (ck, sk) = gen_keys();
322 sk.set_server_key();
323
324 for i in 144..=255 {
325 for j in 100..=255 {
326 let m0 = i;
327 let m1 = j;
328 let c0 = ck.encrypt(&m0);
329 let c1 = ck.encrypt(&m1);
330
331 assert!(ck.decrypt(&c0) == m0);
332 assert!(ck.decrypt(&c1) == m1);
333
334 // Arithmetic
335 {
336 {
337 // Add
338 let mut c_m0_plus_m1 = FheUint8 {
339 data: c0.data().to_vec(),
340 };
341 c_m0_plus_m1 += &c1;
342 let m0_plus_m1 = ck.decrypt(&c_m0_plus_m1);
343 assert_eq!(
344 m0_plus_m1,
345 m0.wrapping_add(m1),
346 "Expected {} but got {m0_plus_m1} for {i}+{j}",
347 m0.wrapping_add(m1)
348 );
349 }
350 {
351 // Sub
352 let c_sub = &c0 - &c1;
353 let m0_sub_m1 = ck.decrypt(&c_sub);
354 assert_eq!(
355 m0_sub_m1,
356 m0.wrapping_sub(m1),
357 "Expected {} but got {m0_sub_m1} for {i}-{j}",
358 m0.wrapping_sub(m1)
359 );
360 }
361
362 {
363 // Mul
364 let c_m0m1 = &c0 * &c1;
365 let m0m1 = ck.decrypt(&c_m0m1);
366 assert_eq!(
367 m0m1,
368 m0.wrapping_mul(m1),
369 "Expected {} but got {m0m1} for {i}x{j}",
370 m0.wrapping_mul(m1)
371 );
372 }
373
374 // Div & Rem
375 {
376 let (c_quotient, c_rem) = c0.div_rem(&c1);
377 let m_quotient = ck.decrypt(&c_quotient);
378 let m_remainder = ck.decrypt(&c_rem);
379 if j != 0 {
380 let (q, r) = i.div_rem_euclid(&j);
381 assert_eq!(
382 m_quotient, q,
383 "Expected {} but got {m_quotient} for {i}/{j}",
384 q
385 );
386 assert_eq!(
387 m_remainder, r,
388 "Expected {} but got {m_quotient} for {i}%{j}",
389 r
390 );
391 } else {
392 assert_eq!(
393 m_quotient, 255,
394 "Expected 255 but got {m_quotient}. Case div by zero"
395 );
396 assert_eq!(
397 m_remainder, i,
398 "Expected {i} but got {m_quotient}. Case div by zero"
399 )
400 }
401 }
402 }
403
404 // Comparisons
405 {
406 {
407 let c_eq = c0.eq(&c1);
408 let is_eq = ck.decrypt(&c_eq);
409 assert_eq!(
410 is_eq,
411 i == j,
412 "Expected {} but got {is_eq} for {i}=={j}",
413 i == j
414 );
415 }
416
417 {
418 let c_gt = c0.gt(&c1);
419 let is_gt = ck.decrypt(&c_gt);
420 assert_eq!(
421 is_gt,
422 i > j,
423 "Expected {} but got {is_gt} for {i}>{j}",
424 i > j
425 );
426 }
427
428 {
429 let c_lt = c0.lt(&c1);
430 let is_lt = ck.decrypt(&c_lt);
431 assert_eq!(
432 is_lt,
433 i < j,
434 "Expected {} but got {is_lt} for {i}<{j}",
435 i < j
436 );
437 }
438
439 {
440 let c_ge = c0.ge(&c1);
441 let is_ge = ck.decrypt(&c_ge);
442 assert_eq!(
443 is_ge,
444 i >= j,
445 "Expected {} but got {is_ge} for {i}>={j}",
446 i >= j
447 );
448 }
449
450 {
451 let c_le = c0.le(&c1);
452 let is_le = ck.decrypt(&c_le);
453 assert_eq!(
454 is_le,
455 i <= j,
456 "Expected {} but got {is_le} for {i}<={j}",
457 i <= j
458 );
459 }
460 }
461 }
462 }
463 }
464
465 #[test]
466 fn fheuint8_test_multi_party() {
467 set_parameter_set(crate::ParameterSelector::MultiPartyLessThan16);
468 set_mp_seed([0; 32]);
469
470 let parties = 8;
471
472 // client keys and public key share
473 let cks = (0..parties)
474 .into_iter()
475 .map(|i| gen_client_key())
476 .collect_vec();
477
478 // round 1: generate pulic key shares
479 let pk_shares = cks.iter().map(|key| gen_mp_keys_phase1(key)).collect_vec();
480
481 let public_key = aggregate_public_key_shares(&pk_shares);
482
483 // round 2: generate server key shares
484 let server_key_shares = cks
485 .iter()
486 .map(|key| gen_mp_keys_phase2(key, &public_key))
487 .collect_vec();
488
489 // server aggregates the server key
490 let server_key = aggregate_server_key_shares(&server_key_shares);
491 server_key.set_server_key();
492
493 // Clients use Pk to encrypt private inputs
494 let a = 8u8;
495 let b = 10u8;
496 let c = 155u8;
497 let ct_a = public_key.encrypt(&a);
498 let ct_b = public_key.encrypt(&b);
499 let ct_c = public_key.encrypt(&c);
500
501 let now = std::time::Instant::now();
502 // server computes
503 // a*b + c
504 let mut ct_ab = &ct_a * &ct_b;
505 ct_ab += &ct_c;
506 println!("Circuit time: {:?}", now.elapsed());
507
508 // decrypt ab and check
509 // generate decryption shares
510 let decryption_shares = cks
511 .iter()
512 .map(|k| k.gen_decryption_share(&ct_ab))
513 .collect_vec();
514
515 // aggregate and decryption ab
516 let ab_add_c = cks[0].aggregate_decryption_shares(&ct_ab, &decryption_shares);
517 assert!(ab_add_c == (a.wrapping_mul(b)).wrapping_add(c));
518 }
519}