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
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
// Copyright (c) Facebook, Inc. and its affiliates.
//
// This source code is licensed under the MIT license found in the
// LICENSE file in the root directory of this source tree.

use super::{exp_acc, Digest, ElementHasher, Hasher};
use core::convert::TryInto;
use math::{fields::f62::BaseElement, FieldElement, StarkField};

mod digest;
pub use digest::ElementDigest;

#[cfg(test)]
mod tests;

// CONSTANTS
// ================================================================================================

/// Sponge state is set to 12 field elements or 744 bytes; 8 elements are reserved for rate and
/// the remaining 4 elements are reserved for capacity.
const STATE_WIDTH: usize = 12;
const RATE_WIDTH: usize = 8;

/// The output of the hash function is a digest which consists of 4 field elements or 31 bytes.
const DIGEST_SIZE: usize = 4;

/// The number of rounds is set to 7 to target 124-bit security level with 40% security margin;
/// computed using algorithm 7 from <https://eprint.iacr.org/2020/1143.pdf>
const NUM_ROUNDS: usize = 7;

/// S-Box and Inverse S-Box powers;
/// computed using algorithm 6 from <https://eprint.iacr.org/2020/1143.pdf>
///
/// The constants are defined for tests only because the exponentiations in the code are unrolled
/// for efficiency reasons.
#[cfg(test)]
const ALPHA: u32 = 3;
#[cfg(test)]
const INV_ALPHA: u64 = 3074416663688030891;

// HASHER IMPLEMENTATION
// ================================================================================================

/// Implementation of [Hasher] trait for Rescue Prime hash function with 248-bit output.
///
/// The hash function is implemented according to the Rescue Prime
/// [specifications](https://eprint.iacr.org/2020/1143.pdf) with the following exception:
/// * We set the number of rounds to 7, which implies a 40% security margin instead of the 50%
///   margin used in the specifications (a 50% margin rounds up to 8 rounds). The primary
///   motivation for this is that having the number of rounds be one less than a power of two
///   simplifies AIR design for computations involving the hash function.
/// * When hashing a sequence of elements, we do not append Fp(1) followed by Fp(0) elements
///   to the end of the sequence as padding. Instead, we initialize one of the capacity elements
///   to the number of elements to be hashed, and pad the sequence with Fp(0) elements only. This
///   ensures consistency of hash outputs between different hashing methods (see section below).
///   However, it also means that our instantiation of Rescue Prime cannot be used in a stream
///   mode as the number of elements to be hashed must be known upfront.
///
/// The parameters used to instantiate the function are:
/// * Field: 62-bit prime field with modulus 2^62 - 111 * 2^39 + 1.
/// * State width: 12 field elements.
/// * Capacity size: 4 field elements.
/// * Number of founds: 7.
/// * S-Box degree: 3.
///
/// The above parameters target 124-bit security level. The digest consists of four field elements
/// and it can be serialized into 31 bytes (248 bits).
///
/// ## Hash output consistency
/// Functions [hash_elements()](Rp62_248::hash_elements), [merge()](Rp62_248::merge), and
/// [merge_with_int()](Rp62_248::merge_with_int) are internally consistent. That is, computing
/// a hash for the same set of elements using these functions will always produce the same
/// result. For example, merging two digests using [merge()](Rp62_248::merge) will produce the
/// same result as hashing 8 elements which make up these digests using
/// [hash_elements()](Rp62_248::hash_elements) function.
///
/// However, [hash()](Rp62_248::hash) function is not consistent with functions mentioned above.
/// For example, if we take two field elements, serialize them to bytes and hash them using
/// [hash()](Rp62_248::hash), the result will differ from the result obtained by hashing these
/// elements directly using [hash_elements()](Rp62_248::hash_elements) function. The reason for
/// this difference is that [hash()](Rp62_248::hash) function needs to be able to handle
/// arbitrary binary strings, which may or may not encode valid field elements - and thus,
/// deserialization procedure used by this function is different from the procedure used to
/// deserialize valid field elements.
///
/// Thus, if the underlying data consists of valid field elements, it might make more sense
/// to deserialize them into field elements and then hash them using
/// [hash_elements()](Rp62_248::hash_elements) function rather then hashing the serialized bytes
/// using [hash()](Rp62_248::hash) function.
pub struct Rp62_248();

impl Hasher for Rp62_248 {
    type Digest = ElementDigest;

    fn hash(bytes: &[u8]) -> Self::Digest {
        // compute the number of elements required to represent the string; we will be processing
        // the string in 7-byte chunks, thus the number of elements will be equal to the number
        // of such chunks (including a potential partial chunk at the end).
        let num_elements = if bytes.len() % 7 == 0 {
            bytes.len() / 7
        } else {
            bytes.len() / 7 + 1
        };

        // initialize state to all zeros, except for the last element of the capacity part, which
        // is set to the number of elements to be hashed. this is done so that adding zero elements
        // at the end of the list always results in a different hash.
        let mut state = [BaseElement::ZERO; STATE_WIDTH];
        state[STATE_WIDTH - 1] = BaseElement::new(num_elements as u64);

        // break the string into 7-byte chunks, convert each chunk into a field element, and
        // absorb the element into the rate portion of the state. we use 7-byte chunks because
        // every 7-byte chunk is guaranteed to map to some field element.
        let mut i = 0;
        let mut buf = [0_u8; 8];
        for chunk in bytes.chunks(7) {
            if i < num_elements - 1 {
                buf[..7].copy_from_slice(chunk);
            } else {
                // if we are dealing with the last chunk, it may be smaller than 7 bytes long, so
                // we need to handle it slightly differently. we also append a byte with value 1
                // to the end of the string; this pads the string in such a way that adding
                // trailing zeros results in different hash
                let chunk_len = chunk.len();
                buf = [0_u8; 8];
                buf[..chunk_len].copy_from_slice(chunk);
                buf[chunk_len] = 1;
            }

            // convert the bytes into a filed element and absorb it into the rate portion of the
            // state; if the rate is filled up, apply the Rescue permutation and start absorbing
            // again from zero index.
            state[i] += BaseElement::new(u64::from_le_bytes(buf));
            i += 1;
            if i % RATE_WIDTH == 0 {
                apply_permutation(&mut state);
                i = 0;
            }
        }

        // if we absorbed some elements but didn't apply a permutation to them (would happen when
        // the number of elements is not a multiple of RATE_WIDTH), apply the Rescue permutation.
        // we don't need to apply any extra padding because we injected total number of elements
        // in the input list into the capacity portion of the state during initialization.
        if i > 0 {
            apply_permutation(&mut state);
        }

        // return the first 4 elements of the state as hash result
        ElementDigest::new(state[..DIGEST_SIZE].try_into().unwrap())
    }

    fn merge(values: &[Self::Digest; 2]) -> Self::Digest {
        // initialize the state by copying the digest elements into the rate portion of the state
        // (8 total elements), and set the last capacity element to 8 (the number of elements to
        // be hashed).
        let mut state = [BaseElement::ZERO; STATE_WIDTH];
        state[..RATE_WIDTH].copy_from_slice(Self::Digest::digests_as_elements(values));
        state[STATE_WIDTH - 1] = BaseElement::new(RATE_WIDTH as u64);

        // apply the Rescue permutation and return the first four elements of the state
        apply_permutation(&mut state);
        ElementDigest::new(state[..DIGEST_SIZE].try_into().unwrap())
    }

    fn merge_with_int(seed: Self::Digest, value: u64) -> Self::Digest {
        // initialize the state as follows:
        // - seed is copied into the first 4 elements of the state.
        // - if the value fits into a single field element, copy it into the fifth state element
        //   and set the last capacity element to 5 (the number of elements to be hashed).
        // - if the value doesn't fit into a single field element, split it into two field
        //   elements, copy them into state elements 5 and 6, and set the last capacity element
        //   to 6.
        let mut state = [BaseElement::ZERO; STATE_WIDTH];
        state[..DIGEST_SIZE].copy_from_slice(seed.as_elements());
        state[DIGEST_SIZE] = BaseElement::new(value);
        if value < BaseElement::MODULUS {
            state[STATE_WIDTH - 1] = BaseElement::new(DIGEST_SIZE as u64 + 1);
        } else {
            state[DIGEST_SIZE + 1] = BaseElement::new(value / BaseElement::MODULUS);
            state[STATE_WIDTH - 1] = BaseElement::new(DIGEST_SIZE as u64 + 2);
        }

        // apply the Rescue permutation and return the first four elements of the state
        apply_permutation(&mut state);
        ElementDigest::new(state[..DIGEST_SIZE].try_into().unwrap())
    }
}

impl ElementHasher for Rp62_248 {
    type BaseField = BaseElement;

    fn hash_elements<E: FieldElement<BaseField = Self::BaseField>>(elements: &[E]) -> Self::Digest {
        // convert the elements into a list of base field elements
        let elements = E::as_base_elements(elements);

        // initialize state to all zeros, except for the last element of the capacity part, which
        // is set to the number of elements to be hashed. this is done so that adding zero elements
        // at the end of the list always results in a different hash.
        let mut state = [BaseElement::ZERO; STATE_WIDTH];
        state[STATE_WIDTH - 1] = BaseElement::new(elements.len() as u64);

        // absorb elements into the state one by one until the rate portion of the state is filled
        // up; then apply the Rescue permutation and start absorbing again; repeat until all
        // elements have been absorbed
        let mut i = 0;
        for &element in elements.iter() {
            state[i] += element;
            i += 1;
            if i % RATE_WIDTH == 0 {
                apply_permutation(&mut state);
                i = 0;
            }
        }

        // if we absorbed some elements but didn't apply a permutation to them (would happen when
        // the number of elements is not a multiple of RATE_WIDTH), apply the Rescue permutation.
        // we don't need to apply any extra padding because we injected total number of elements
        // in the input list into the capacity portion of the state during initialization.
        if i > 0 {
            apply_permutation(&mut state);
        }

        // return the first 4 elements of the state as hash result
        ElementDigest::new(state[..DIGEST_SIZE].try_into().unwrap())
    }
}

// RESCUE PERMUTATION
// ================================================================================================

/// Applies Rescue-XLIX permutation to the provided state.
///
/// Implementation is based on algorithm 3 from <https://eprint.iacr.org/2020/1143.pdf>
fn apply_permutation(state: &mut [BaseElement; STATE_WIDTH]) {
    // apply round function 7 times; this provides 128-bit security with 40% security margin
    for i in 0..NUM_ROUNDS {
        apply_round(state, i);
    }
}

/// Rescue-XLIX round function.
#[inline(always)]
fn apply_round(state: &mut [BaseElement; STATE_WIDTH], round: usize) {
    // apply first half of Rescue round
    apply_sbox(state);
    apply_mds(state);
    add_constants(state, &ARK1[round]);

    // apply second half of Rescue round
    apply_inv_sbox(state);
    apply_mds(state);
    add_constants(state, &ARK2[round]);
}

// HELPER FUNCTIONS
// ================================================================================================

#[inline(always)]
fn apply_mds(state: &mut [BaseElement; STATE_WIDTH]) {
    let mut result = [BaseElement::ZERO; STATE_WIDTH];
    result.iter_mut().zip(MDS).for_each(|(r, mds_row)| {
        state.iter().zip(mds_row).for_each(|(&s, m)| {
            *r += m * s;
        });
    });
    *state = result
}

#[inline(always)]
fn add_constants(state: &mut [BaseElement; STATE_WIDTH], ark: &[BaseElement; STATE_WIDTH]) {
    state.iter_mut().zip(ark).for_each(|(s, &k)| *s += k);
}

#[inline(always)]
fn apply_sbox(state: &mut [BaseElement; STATE_WIDTH]) {
    state.iter_mut().for_each(|v| *v = v.cube())
}

#[inline(always)]
fn apply_inv_sbox(state: &mut [BaseElement; STATE_WIDTH]) {
    // compute base^3074416663688030891 using 69 multiplications per array element
    // 3074416663688030891 = b10101010101010100001011010101010101010101010101010101010101011

    // compute base^10
    let mut t1 = *state;
    t1.iter_mut().for_each(|t1| *t1 = t1.square());

    // compute base^1010
    let t2 = exp_acc::<BaseElement, STATE_WIDTH, 2>(t1, t1);

    // compute base^10101010
    let t4 = exp_acc::<BaseElement, STATE_WIDTH, 4>(t2, t2);

    // compute base^1010101010101010
    let t8 = exp_acc::<BaseElement, STATE_WIDTH, 8>(t4, t4);

    // compute base^10101010101010100001010
    let acc = exp_acc::<BaseElement, STATE_WIDTH, 7>(t8, t2);

    // compute base^10101010101010100001011010101010101010
    let acc = exp_acc::<BaseElement, STATE_WIDTH, 15>(acc, t8);

    // compute base^101010101010101000010110101010101010101010101010101010
    let acc = exp_acc::<BaseElement, STATE_WIDTH, 16>(acc, t8);

    // compute base^10101010101010100001011010101010101010101010101010101010101010
    let acc = exp_acc::<BaseElement, STATE_WIDTH, 8>(acc, t4);

    // compute base^10101010101010100001011010101010101010101010101010101010101011
    state.iter_mut().zip(acc).for_each(|(s, a)| *s *= a);
}

// MDS
// ================================================================================================
/// Rescue MDS matrix
/// Computed using algorithm 4 from <https://eprint.iacr.org/2020/1143.pdf>
const MDS: [[BaseElement; STATE_WIDTH]; STATE_WIDTH] = [
    [
        BaseElement::new(3950144678237376122),
        BaseElement::new(2690153189131774333),
        BaseElement::new(936645784682382348),
        BaseElement::new(3107191214132265415),
        BaseElement::new(2603209838230440664),
        BaseElement::new(1199396433148647196),
        BaseElement::new(1282983482067326228),
        BaseElement::new(461437407589395643),
        BaseElement::new(2214977176974126410),
        BaseElement::new(360795585898440),
        BaseElement::new(4611624977880333167),
        BaseElement::new(265720),
    ],
    [
        BaseElement::new(3536793164176604955),
        BaseElement::new(1911503332938627860),
        BaseElement::new(3418675122760523340),
        BaseElement::new(1504989930332511353),
        BaseElement::new(2722575982003138843),
        BaseElement::new(1431609872573058051),
        BaseElement::new(1192456656548488631),
        BaseElement::new(545546930229576032),
        BaseElement::new(945223199513254881),
        BaseElement::new(1241455355734630133),
        BaseElement::new(4607295377894412377),
        BaseElement::new(52955405230),
    ],
    [
        BaseElement::new(4170851182034451356),
        BaseElement::new(4049722115827050441),
        BaseElement::new(2592958603203603955),
        BaseElement::new(1591126261909367400),
        BaseElement::new(1258275846807863107),
        BaseElement::new(1998950167196902314),
        BaseElement::new(3042201191319512244),
        BaseElement::new(543039388605157758),
        BaseElement::new(1398996793391337371),
        BaseElement::new(4366181202594792993),
        BaseElement::new(2647705527662157444),
        BaseElement::new(9741692640081640),
    ],
    [
        BaseElement::new(2734904247639408359),
        BaseElement::new(4279587509601476247),
        BaseElement::new(4485482368008952587),
        BaseElement::new(3891839128198288856),
        BaseElement::new(3605615068318190226),
        BaseElement::new(4481033712623965820),
        BaseElement::new(4511906145686918697),
        BaseElement::new(3379942354449020806),
        BaseElement::new(3990599459674901680),
        BaseElement::new(3930378924631282611),
        BaseElement::new(2736309679810514295),
        BaseElement::new(4088651356677543187),
    ],
    [
        BaseElement::new(842258110397353220),
        BaseElement::new(3379876823114508085),
        BaseElement::new(1075495666387844288),
        BaseElement::new(2308322198399190449),
        BaseElement::new(535073101119307124),
        BaseElement::new(2549013922555968548),
        BaseElement::new(2089967165864721761),
        BaseElement::new(1833259538539094178),
        BaseElement::new(1286299364399671252),
        BaseElement::new(3116429868056012525),
        BaseElement::new(3765145590440791140),
        BaseElement::new(276983628385769116),
    ],
    [
        BaseElement::new(1299560456850023050),
        BaseElement::new(4414989737001639740),
        BaseElement::new(627780834867342283),
        BaseElement::new(1711770898052004155),
        BaseElement::new(1979604523493335895),
        BaseElement::new(33488920757262988),
        BaseElement::new(3296083413419576217),
        BaseElement::new(716111559512999319),
        BaseElement::new(1748727787185165915),
        BaseElement::new(2725007460252215875),
        BaseElement::new(2185047820717910109),
        BaseElement::new(2319951565550756140),
    ],
    [
        BaseElement::new(4184625686841861769),
        BaseElement::new(1784981074793151883),
        BaseElement::new(502457291852703062),
        BaseElement::new(345570060311611630),
        BaseElement::new(2471821400707240604),
        BaseElement::new(2133038110899525730),
        BaseElement::new(939120245208093777),
        BaseElement::new(4151312447988641414),
        BaseElement::new(210626922136569504),
        BaseElement::new(2121768124528492214),
        BaseElement::new(3469035391047007665),
        BaseElement::new(743768221345332434),
    ],
    [
        BaseElement::new(2145694559473526100),
        BaseElement::new(1632268183143575659),
        BaseElement::new(440280249850363795),
        BaseElement::new(1074260737240252344),
        BaseElement::new(434235372443698697),
        BaseElement::new(4579079558834190297),
        BaseElement::new(507988595809300562),
        BaseElement::new(746255436130103157),
        BaseElement::new(1959107915115263608),
        BaseElement::new(4030330146733953284),
        BaseElement::new(3748621471482452510),
        BaseElement::new(1760002751403551673),
    ],
    [
        BaseElement::new(2299194066166806303),
        BaseElement::new(2406031288159683129),
        BaseElement::new(3724303300393675060),
        BaseElement::new(3136303930848425791),
        BaseElement::new(842217609243732235),
        BaseElement::new(2433222065782096659),
        BaseElement::new(1853915347332186193),
        BaseElement::new(3565339054535487990),
        BaseElement::new(3159752035320462032),
        BaseElement::new(1001592926358592140),
        BaseElement::new(1070575826169209928),
        BaseElement::new(2177302522881920563),
    ],
    [
        BaseElement::new(2207526749486243134),
        BaseElement::new(4032720262691072240),
        BaseElement::new(1260214313840482146),
        BaseElement::new(3621152551536391331),
        BaseElement::new(1609693674346558276),
        BaseElement::new(1076797379868177960),
        BaseElement::new(1050224695423079188),
        BaseElement::new(1679887683779537233),
        BaseElement::new(1053394941293588429),
        BaseElement::new(2176319632402176708),
        BaseElement::new(807051555764923088),
        BaseElement::new(2483141537228001953),
    ],
    [
        BaseElement::new(873986056056007361),
        BaseElement::new(2985158312969304104),
        BaseElement::new(2082576071668149043),
        BaseElement::new(1607709264834493266),
        BaseElement::new(1027130385873843589),
        BaseElement::new(3876861839368848637),
        BaseElement::new(2999813843878199730),
        BaseElement::new(3252530728916107838),
        BaseElement::new(4464640832314938694),
        BaseElement::new(1978539358398864357),
        BaseElement::new(3425590232595452442),
        BaseElement::new(3706838041850115299),
    ],
    [
        BaseElement::new(3407508207732360664),
        BaseElement::new(2899952415584588394),
        BaseElement::new(282047285293952955),
        BaseElement::new(4147714396995528527),
        BaseElement::new(1141786266584343815),
        BaseElement::new(3523991864183271024),
        BaseElement::new(1659008334442446407),
        BaseElement::new(2857663046861472404),
        BaseElement::new(1954265424153359502),
        BaseElement::new(4018750979872307732),
        BaseElement::new(494911809436924696),
        BaseElement::new(1282149942051721903),
    ],
];

// ROUND CONSTANTS
// ================================================================================================

/// Rescue round constants;
/// computed using algorithm 5 from <https://eprint.iacr.org/2020/1143.pdf>
///
/// The constants are broken up into two arrays ARK1 and ARK2; ARK1 contains the constants for the
/// first half of Rescue round, and ARK2 contains constants for the second half of Rescue round.
pub const ARK1: [[BaseElement; STATE_WIDTH]; NUM_ROUNDS] = [
    [
        BaseElement::new(2066114551762569441),
        BaseElement::new(3806895469920197238),
        BaseElement::new(4101271467144175579),
        BaseElement::new(597783788093439290),
        BaseElement::new(3459529549731874958),
        BaseElement::new(3361732357449281221),
        BaseElement::new(4510044102131299796),
        BaseElement::new(2674251637583411151),
        BaseElement::new(4589456981709905074),
        BaseElement::new(97204927704726530),
        BaseElement::new(3366467278170867590),
        BaseElement::new(1661995649761352250),
    ],
    [
        BaseElement::new(2552080730515318124),
        BaseElement::new(4551129269607279176),
        BaseElement::new(3896238353185798118),
        BaseElement::new(4378451547412130464),
        BaseElement::new(1120678946404787820),
        BaseElement::new(3392815550656692052),
        BaseElement::new(3397267446269039551),
        BaseElement::new(2148161493216445570),
        BaseElement::new(449851947043698998),
        BaseElement::new(2745778316253333994),
        BaseElement::new(3247100729373266485),
        BaseElement::new(1474512661374883327),
    ],
    [
        BaseElement::new(3875405236566248698),
        BaseElement::new(3509172052827303011),
        BaseElement::new(232674088014396347),
        BaseElement::new(4189609763147780999),
        BaseElement::new(3106901133683704323),
        BaseElement::new(592695797873090171),
        BaseElement::new(266738566669046215),
        BaseElement::new(2668509039085882180),
        BaseElement::new(950720373611234910),
        BaseElement::new(1192091586747406812),
        BaseElement::new(2245360993531047612),
        BaseElement::new(2031514636218081872),
    ],
    [
        BaseElement::new(2291456653144584105),
        BaseElement::new(869259464485808552),
        BaseElement::new(1154055231930493301),
        BaseElement::new(1843073679205946182),
        BaseElement::new(1748748883129851856),
        BaseElement::new(4085632850766581010),
        BaseElement::new(2907511654177734852),
        BaseElement::new(1563252740420931271),
        BaseElement::new(57166044462862224),
        BaseElement::new(3237323403752048612),
        BaseElement::new(4563484427236835576),
        BaseElement::new(2956709587309713553),
    ],
    [
        BaseElement::new(2157779262561212790),
        BaseElement::new(2452020513593893218),
        BaseElement::new(3051597722203497560),
        BaseElement::new(3131962147511514023),
        BaseElement::new(194930663253195526),
        BaseElement::new(930794074695110797),
        BaseElement::new(3616451697350340387),
        BaseElement::new(1493869649774878568),
        BaseElement::new(2790579710588613698),
        BaseElement::new(4552593272704308029),
        BaseElement::new(931863165972727433),
        BaseElement::new(2628222466499909093),
    ],
    [
        BaseElement::new(628982718083809865),
        BaseElement::new(3809487906119235546),
        BaseElement::new(1412055838972795717),
        BaseElement::new(2702758340764464061),
        BaseElement::new(643165380746471120),
        BaseElement::new(1755475976486779630),
        BaseElement::new(4322584783908582556),
        BaseElement::new(2377752666356883186),
        BaseElement::new(3806838324704149861),
        BaseElement::new(3978620600887524391),
        BaseElement::new(2546609133879704944),
        BaseElement::new(3704323050566652251),
    ],
    [
        BaseElement::new(364418616620607840),
        BaseElement::new(557500673241722848),
        BaseElement::new(2838167312179774894),
        BaseElement::new(919171238566781484),
        BaseElement::new(1810286722734245651),
        BaseElement::new(2647811277753845608),
        BaseElement::new(1083073358474695843),
        BaseElement::new(2087740333294235353),
        BaseElement::new(3237593972479805167),
        BaseElement::new(2979012086287276314),
        BaseElement::new(4247318354894968843),
        BaseElement::new(4339035876293932168),
    ],
];

pub const ARK2: [[BaseElement; STATE_WIDTH]; NUM_ROUNDS] = [
    [
        BaseElement::new(3819036781602939606),
        BaseElement::new(887046499825451011),
        BaseElement::new(2129644207518417092),
        BaseElement::new(2927054444958183703),
        BaseElement::new(3938394192009721127),
        BaseElement::new(4350492790583122386),
        BaseElement::new(3932489874389553135),
        BaseElement::new(2187735113981662094),
        BaseElement::new(2707268329521558754),
        BaseElement::new(1672475830798880457),
        BaseElement::new(577661991381759440),
        BaseElement::new(4202413457369478629),
    ],
    [
        BaseElement::new(2386138289504492057),
        BaseElement::new(3614836749985123032),
        BaseElement::new(1959364639655691456),
        BaseElement::new(3952161783467742979),
        BaseElement::new(2113797503569123694),
        BaseElement::new(2706761515468719677),
        BaseElement::new(1408899580454624727),
        BaseElement::new(1752562999883762712),
        BaseElement::new(2699036399761024947),
        BaseElement::new(2111974313315470120),
        BaseElement::new(1945634303007041433),
        BaseElement::new(603680138767490486),
    ],
    [
        BaseElement::new(216541366065294490),
        BaseElement::new(1663917238463860974),
        BaseElement::new(3681161841551456227),
        BaseElement::new(1463044976083347872),
        BaseElement::new(4293067359825676566),
        BaseElement::new(3701547299239100959),
        BaseElement::new(2198012560927400476),
        BaseElement::new(924090339017537873),
        BaseElement::new(4592565695695653575),
        BaseElement::new(2568652539159558382),
        BaseElement::new(2556673802560280889),
        BaseElement::new(2055200673419696274),
    ],
    [
        BaseElement::new(675825972975288687),
        BaseElement::new(157304917963529210),
        BaseElement::new(2874195676109427150),
        BaseElement::new(400733584567227315),
        BaseElement::new(982698402204661622),
        BaseElement::new(820183842893732317),
        BaseElement::new(301881572013037058),
        BaseElement::new(1963857632534980766),
        BaseElement::new(4091993061963419897),
        BaseElement::new(4102179200035343013),
        BaseElement::new(886874507443125118),
        BaseElement::new(1900379595653484868),
    ],
    [
        BaseElement::new(663951223276314056),
        BaseElement::new(3247862347650141921),
        BaseElement::new(2405853211128575753),
        BaseElement::new(2313821214725089833),
        BaseElement::new(892865509580640652),
        BaseElement::new(3786801988137677226),
        BaseElement::new(1708051655041482785),
        BaseElement::new(413367975786665969),
        BaseElement::new(4184177931828745920),
        BaseElement::new(1902978742415691889),
        BaseElement::new(3457684352259258126),
        BaseElement::new(2092600929857819767),
    ],
    [
        BaseElement::new(3616150808336931771),
        BaseElement::new(3206846600545625539),
        BaseElement::new(3830153390371624940),
        BaseElement::new(2654199900015314333),
        BaseElement::new(783490214003335242),
        BaseElement::new(3730076606034436027),
        BaseElement::new(3784919641869206369),
        BaseElement::new(2204748845493012644),
        BaseElement::new(448185939031874189),
        BaseElement::new(435945873799083567),
        BaseElement::new(695310862494154666),
        BaseElement::new(2112586212508747422),
    ],
    [
        BaseElement::new(1802926915815728451),
        BaseElement::new(2057340163436909216),
        BaseElement::new(982232855844273391),
        BaseElement::new(1559347186127685318),
        BaseElement::new(1420221884912541505),
        BaseElement::new(4213862187371016442),
        BaseElement::new(476828620219460093),
        BaseElement::new(4518037022029400598),
        BaseElement::new(186346377116487094),
        BaseElement::new(4479404873270208061),
        BaseElement::new(3269764362972891817),
        BaseElement::new(2929967273325723272),
    ],
];