1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
use super::*;
use snarkvm_curves::traits::PairingEngine;
use snarkvm_utilities::{
CanonicalDeserialize,
CanonicalSerialize,
Compress,
FromBytes,
Read,
SerializationError,
ToBytes,
Valid,
Validate,
Write,
};
use anyhow::{anyhow, bail, ensure, Result};
use std::{collections::BTreeMap, ops::Range, sync::Arc};
const NUM_POWERS_15: usize = 1 << 15;
const NUM_POWERS_16: usize = 1 << 16;
const NUM_POWERS_17: usize = 1 << 17;
const NUM_POWERS_18: usize = 1 << 18;
const NUM_POWERS_19: usize = 1 << 19;
const NUM_POWERS_20: usize = 1 << 20;
const NUM_POWERS_21: usize = 1 << 21;
const NUM_POWERS_22: usize = 1 << 22;
const NUM_POWERS_23: usize = 1 << 23;
const NUM_POWERS_24: usize = 1 << 24;
const NUM_POWERS_25: usize = 1 << 25;
const NUM_POWERS_26: usize = 1 << 26;
const NUM_POWERS_27: usize = 1 << 27;
const NUM_POWERS_28: usize = 1 << 28;
const MAX_NUM_POWERS: usize = NUM_POWERS_28;
lazy_static::lazy_static! {
static ref POWERS_OF_BETA_G_15: Vec<u8> = Degree15::load_bytes().expect("Failed to load powers of beta in universal SRS");
static ref SHIFTED_POWERS_OF_BETA_G_15: Vec<u8> = ShiftedDegree15::load_bytes().expect("Failed to load powers of beta in universal SRS");
static ref POWERS_OF_BETA_GAMMA_G: Vec<u8> = Gamma::load_bytes().expect("Failed to load powers of beta wrt gamma * G in universal SRS");
static ref NEG_POWERS_OF_BETA_H: Vec<u8> = NegBeta::load_bytes().expect("Failed to load negative powers of beta in universal SRS");
static ref BETA_H: Vec<u8> = BetaH::load_bytes().expect("Failed to load negative powers of beta in universal SRS");
}
#[derive(Debug, Clone)]
pub struct PowersOfG<E: PairingEngine> {
powers_of_beta_g: PowersOfBetaG<E>,
powers_of_beta_times_gamma_g: Arc<BTreeMap<usize, E::G1Affine>>,
negative_powers_of_beta_h: Arc<BTreeMap<usize, E::G2Affine>>,
beta_h: E::G2Affine,
}
impl<E: PairingEngine> PowersOfG<E> {
pub fn load() -> Result<Self> {
let powers_of_beta_g = PowersOfBetaG::load()?;
let powers_of_beta_times_gamma_g =
Arc::new(BTreeMap::deserialize_uncompressed_unchecked(&**POWERS_OF_BETA_GAMMA_G)?);
let negative_powers_of_beta_h =
Arc::new(BTreeMap::deserialize_uncompressed_unchecked(&**NEG_POWERS_OF_BETA_H)?);
let beta_h = E::G2Affine::deserialize_uncompressed_unchecked(&**BETA_H)?;
let powers = Self { powers_of_beta_g, powers_of_beta_times_gamma_g, negative_powers_of_beta_h, beta_h };
Ok(powers)
}
pub fn download_powers_for(&mut self, range: Range<usize>) -> Result<()> {
self.powers_of_beta_g.download_powers_for(&range)
}
pub fn num_powers(&self) -> usize {
self.powers_of_beta_g.num_powers()
}
pub fn max_num_powers(&self) -> usize {
MAX_NUM_POWERS
}
pub fn powers_of_beta_gamma_g(&self) -> Arc<BTreeMap<usize, E::G1Affine>> {
self.powers_of_beta_times_gamma_g.clone()
}
pub fn power_of_beta_g(&mut self, index: usize) -> Result<E::G1Affine> {
self.powers_of_beta_g.power(index)
}
pub fn powers_of_beta_g(&mut self, range: Range<usize>) -> Result<&[E::G1Affine]> {
self.powers_of_beta_g.powers(range)
}
pub fn negative_powers_of_beta_h(&self) -> Arc<BTreeMap<usize, E::G2Affine>> {
self.negative_powers_of_beta_h.clone()
}
pub fn beta_h(&self) -> E::G2Affine {
self.beta_h
}
}
impl<E: PairingEngine> CanonicalSerialize for PowersOfG<E> {
fn serialize_with_mode<W: Write>(&self, mut writer: W, mode: Compress) -> Result<(), SerializationError> {
self.powers_of_beta_g.serialize_with_mode(&mut writer, mode)?;
self.powers_of_beta_times_gamma_g.serialize_with_mode(&mut writer, mode)?;
self.negative_powers_of_beta_h.serialize_with_mode(&mut writer, mode)?;
self.beta_h.serialize_with_mode(&mut writer, mode)?;
Ok(())
}
fn serialized_size(&self, mode: Compress) -> usize {
self.powers_of_beta_g.serialized_size(mode)
+ self.powers_of_beta_times_gamma_g.serialized_size(mode)
+ self.negative_powers_of_beta_h.serialized_size(mode)
+ self.beta_h.serialized_size(mode)
}
}
impl<E: PairingEngine> CanonicalDeserialize for PowersOfG<E> {
fn deserialize_with_mode<R: Read>(
mut reader: R,
compress: Compress,
validate: Validate,
) -> Result<Self, SerializationError> {
let powers_of_beta_g = PowersOfBetaG::deserialize_with_mode(&mut reader, compress, Validate::No)?;
let powers_of_beta_times_gamma_g =
Arc::new(BTreeMap::deserialize_with_mode(&mut reader, compress, Validate::No)?);
let negative_powers_of_beta_h = Arc::new(BTreeMap::deserialize_with_mode(&mut reader, compress, Validate::No)?);
let beta_h = E::G2Affine::deserialize_with_mode(&mut reader, compress, Validate::No)?;
let powers = Self { powers_of_beta_g, powers_of_beta_times_gamma_g, negative_powers_of_beta_h, beta_h };
if let Validate::Yes = validate {
powers.check()?;
}
Ok(powers)
}
}
impl<E: PairingEngine> Valid for PowersOfG<E> {
fn check(&self) -> Result<(), SerializationError> {
self.powers_of_beta_g.check()?;
self.powers_of_beta_times_gamma_g.check()?;
self.negative_powers_of_beta_h.check()?;
self.beta_h.check()
}
}
impl<E: PairingEngine> FromBytes for PowersOfG<E> {
fn read_le<R: Read>(reader: R) -> std::io::Result<Self> {
Self::deserialize_with_mode(reader, Compress::No, Validate::No).map_err(|e| e.into())
}
}
impl<E: PairingEngine> ToBytes for PowersOfG<E> {
fn write_le<W: Write>(&self, writer: W) -> std::io::Result<()> {
self.serialize_with_mode(writer, Compress::No).map_err(|e| e.into())
}
}
#[derive(Debug, Clone, CanonicalSerialize, CanonicalDeserialize)]
pub struct PowersOfBetaG<E: PairingEngine> {
powers_of_beta_g: Vec<E::G1Affine>,
shifted_powers_of_beta_g: Vec<E::G1Affine>,
}
impl<E: PairingEngine> PowersOfBetaG<E> {
pub fn num_powers(&self) -> usize {
self.powers_of_beta_g.len()
}
fn load() -> Result<Self> {
let powers_of_beta_g = Vec::deserialize_uncompressed_unchecked(&**POWERS_OF_BETA_G_15)?;
ensure!(powers_of_beta_g.len() == NUM_POWERS_15, "Incorrect number of powers in the recovered SRS");
let shifted_powers_of_beta_g = Vec::deserialize_uncompressed_unchecked(&**SHIFTED_POWERS_OF_BETA_G_15)?;
ensure!(shifted_powers_of_beta_g.len() == NUM_POWERS_15, "Incorrect number of powers in the recovered SRS");
Ok(PowersOfBetaG { powers_of_beta_g, shifted_powers_of_beta_g })
}
pub fn available_powers(&self) -> (Range<usize>, Range<usize>) {
if !self.shifted_powers_of_beta_g.is_empty() {
let lower_shifted_bound = MAX_NUM_POWERS - self.shifted_powers_of_beta_g.len();
((0..self.powers_of_beta_g.len()), (lower_shifted_bound..MAX_NUM_POWERS))
} else {
assert_eq!(self.powers_of_beta_g.len(), MAX_NUM_POWERS, "Incorrect number of powers in the recovered SRS");
((0..MAX_NUM_POWERS), (0..MAX_NUM_POWERS))
}
}
fn contains_in_normal_powers(&self, range: &Range<usize>) -> bool {
let (normal, _) = self.available_powers();
normal.contains(&range.start) && (normal.end >= range.end)
}
fn contains_in_shifted_powers(&self, range: &Range<usize>) -> bool {
let (_, shifted) = self.available_powers();
shifted.contains(&range.start) && (shifted.end >= range.end)
}
fn contains_powers(&self, range: &Range<usize>) -> bool {
self.contains_in_normal_powers(range) || self.contains_in_shifted_powers(range)
}
fn distance_from_normal_of(&self, range: &Range<usize>) -> usize {
(range.end as isize - self.available_powers().0.end as isize).unsigned_abs()
}
fn distance_from_shifted_of(&self, range: &Range<usize>) -> usize {
(range.start as isize - self.available_powers().1.start as isize).unsigned_abs()
}
fn shifted_powers(&self, range: Range<usize>) -> Result<&[E::G1Affine]> {
ensure!(
self.contains_in_shifted_powers(&range),
"Requested range is not contained in the available shifted powers"
);
if range.start < MAX_NUM_POWERS / 2 {
ensure!(self.shifted_powers_of_beta_g.is_empty());
Ok(&self.powers_of_beta_g[range])
} else {
let lower = self.shifted_powers_of_beta_g.len() - (MAX_NUM_POWERS - range.start);
let upper = self.shifted_powers_of_beta_g.len() - (MAX_NUM_POWERS - range.end);
Ok(&self.shifted_powers_of_beta_g[lower..upper])
}
}
fn normal_powers(&self, range: Range<usize>) -> Result<&[E::G1Affine]> {
ensure!(self.contains_in_normal_powers(&range), "Requested range is not contained in the available powers");
Ok(&self.powers_of_beta_g[range])
}
fn power(&mut self, target: usize) -> Result<E::G1Affine> {
self.powers(target..(target + 1)).map(|s| s[0])
}
fn powers(&mut self, range: Range<usize>) -> Result<&[E::G1Affine]> {
if range.is_empty() {
return Ok(&self.powers_of_beta_g[0..0]);
}
ensure!(range.start < range.end, "Lower power must be less than upper power");
ensure!(range.end <= MAX_NUM_POWERS, "Upper bound must be less than the maximum number of powers");
if !self.contains_powers(&range) {
self.download_powers_for(&range)?;
}
match self.contains_in_normal_powers(&range) {
true => self.normal_powers(range),
false => self.shifted_powers(range),
}
}
pub fn download_powers_for(&mut self, range: &Range<usize>) -> Result<()> {
if self.contains_in_normal_powers(range) || self.contains_in_shifted_powers(range) {
return Ok(());
}
let half_max = MAX_NUM_POWERS / 2;
if (range.start <= half_max) && (range.end > half_max) {
self.download_powers_up_to(range.end)?;
self.shifted_powers_of_beta_g = Vec::new();
} else if self.distance_from_shifted_of(range) < self.distance_from_normal_of(range) {
self.download_shifted_powers_from(range.start)?;
} else {
self.download_powers_up_to(range.end)?;
}
Ok(())
}
fn download_powers_up_to(&mut self, end: usize) -> Result<()> {
let final_power_of_two =
end.checked_next_power_of_two().ok_or_else(|| anyhow!("Requesting too many powers"))?;
ensure!(final_power_of_two <= MAX_NUM_POWERS, "Requesting more powers than exist in the SRS");
let current_power_of_two = self
.powers_of_beta_g
.len()
.checked_next_power_of_two()
.ok_or_else(|| anyhow!("The current degree is too large"))?;
let mut download_queue = Vec::with_capacity(14);
let mut accumulator = current_power_of_two * 2;
while accumulator <= final_power_of_two {
download_queue.push(accumulator);
accumulator =
accumulator.checked_mul(2).ok_or_else(|| anyhow!("Overflowed while requesting a larger degree"))?;
}
ensure!(final_power_of_two * 2 == accumulator, "Ensure the loop terminates at the right power of two");
let additional_size = final_power_of_two
.checked_sub(self.powers_of_beta_g.len())
.ok_or_else(|| anyhow!("final_power_of_two is smaller than existing powers"))?;
self.powers_of_beta_g.reserve(additional_size);
for num_powers in &download_queue {
#[cfg(debug_assertions)]
println!("Loading {num_powers} powers");
let additional_bytes = match *num_powers {
NUM_POWERS_16 => Degree16::load_bytes()?,
NUM_POWERS_17 => Degree17::load_bytes()?,
NUM_POWERS_18 => Degree18::load_bytes()?,
NUM_POWERS_19 => Degree19::load_bytes()?,
NUM_POWERS_20 => Degree20::load_bytes()?,
NUM_POWERS_21 => Degree21::load_bytes()?,
NUM_POWERS_22 => Degree22::load_bytes()?,
NUM_POWERS_23 => Degree23::load_bytes()?,
NUM_POWERS_24 => Degree24::load_bytes()?,
NUM_POWERS_25 => Degree25::load_bytes()?,
NUM_POWERS_26 => Degree26::load_bytes()?,
NUM_POWERS_27 => Degree27::load_bytes()?,
NUM_POWERS_28 => Degree28::load_bytes()?,
_ => bail!("Cannot download an invalid degree of '{num_powers}'"),
};
let additional_powers = Vec::deserialize_uncompressed_unchecked(&*additional_bytes)?;
self.powers_of_beta_g.extend(&additional_powers);
}
ensure!(self.powers_of_beta_g.len() == final_power_of_two, "Loaded an incorrect number of powers");
Ok(())
}
fn download_shifted_powers_from(&mut self, start: usize) -> Result<()> {
ensure!(start <= MAX_NUM_POWERS, "Requesting more powers than exist in the SRS");
let final_num_powers = MAX_NUM_POWERS
.checked_sub(start)
.ok_or_else(|| {
anyhow!("Requesting too many powers: `start ({start}) > MAX_NUM_POWERS ({MAX_NUM_POWERS})`")
})?
.checked_next_power_of_two()
.ok_or_else(|| anyhow!("Requesting too many powers"))?; let mut download_queue = Vec::with_capacity(14);
let mut existing_num_powers = self.shifted_powers_of_beta_g.len();
while existing_num_powers < final_num_powers {
existing_num_powers = existing_num_powers
.checked_mul(2)
.ok_or_else(|| anyhow!("Overflowed while requesting additional powers"))?;
download_queue.push(existing_num_powers);
}
download_queue.reverse(); let mut final_powers = Vec::with_capacity(final_num_powers);
for num_powers in &download_queue {
#[cfg(debug_assertions)]
println!("Loading {num_powers} shifted powers");
let additional_bytes = match *num_powers {
NUM_POWERS_16 => ShiftedDegree16::load_bytes()?,
NUM_POWERS_17 => ShiftedDegree17::load_bytes()?,
NUM_POWERS_18 => ShiftedDegree18::load_bytes()?,
NUM_POWERS_19 => ShiftedDegree19::load_bytes()?,
NUM_POWERS_20 => ShiftedDegree20::load_bytes()?,
NUM_POWERS_21 => ShiftedDegree21::load_bytes()?,
NUM_POWERS_22 => ShiftedDegree22::load_bytes()?,
NUM_POWERS_23 => ShiftedDegree23::load_bytes()?,
NUM_POWERS_24 => ShiftedDegree24::load_bytes()?,
NUM_POWERS_25 => ShiftedDegree25::load_bytes()?,
NUM_POWERS_26 => ShiftedDegree26::load_bytes()?,
NUM_POWERS_27 => ShiftedDegree27::load_bytes()?,
_ => bail!("Cannot download an invalid degree of '{num_powers}'"),
};
let additional_powers = Vec::deserialize_uncompressed_unchecked(&*additional_bytes)?;
if final_powers.is_empty() {
final_powers = additional_powers;
} else {
final_powers.extend(additional_powers);
}
}
final_powers.extend(self.shifted_powers_of_beta_g.iter());
self.shifted_powers_of_beta_g = final_powers;
ensure!(
self.shifted_powers_of_beta_g.len() == final_num_powers,
"Loaded an incorrect number of shifted powers"
);
Ok(())
}
}
impl<E: PairingEngine> FromBytes for PowersOfBetaG<E> {
fn read_le<R: Read>(reader: R) -> std::io::Result<Self> {
Self::deserialize_with_mode(reader, Compress::No, Validate::No).map_err(|e| e.into())
}
}
impl<E: PairingEngine> ToBytes for PowersOfBetaG<E> {
fn write_le<W: Write>(&self, writer: W) -> std::io::Result<()> {
self.serialize_with_mode(writer, Compress::No).map_err(|e| e.into())
}
}