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
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
|
/*
This file is part of GNU Taler
(C) 2019 GNUnet e.V.
GNU Taler is free software; you can redistribute it and/or modify it under the
terms of the GNU General Public License as published by the Free Software
Foundation; either version 3, or (at your option) any later version.
GNU Taler is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with
GNU Taler; see the file COPYING. If not, see <http://www.gnu.org/licenses/>
*/
/**
* Native implementation of GNU Taler crypto.
*/
/**
* Imports.
*/
import * as nacl from "./nacl-fast.js";
import { kdf, kdfKw } from "./kdf.js";
import bigint from "big-integer";
import {
Base32String,
CoinEnvelope,
CoinPublicKeyString,
DenominationPubKey,
DenomKeyType,
HashCodeString,
} from "./talerTypes.js";
import { Logger } from "./logging.js";
export function getRandomBytes(n: number): Uint8Array {
return nacl.randomBytes(n);
}
const encTable = "0123456789ABCDEFGHJKMNPQRSTVWXYZ";
class EncodingError extends Error {
constructor() {
super("Encoding error");
Object.setPrototypeOf(this, EncodingError.prototype);
}
}
function getValue(chr: string): number {
let a = chr;
switch (chr) {
case "O":
case "o":
a = "0;";
break;
case "i":
case "I":
case "l":
case "L":
a = "1";
break;
case "u":
case "U":
a = "V";
}
if (a >= "0" && a <= "9") {
return a.charCodeAt(0) - "0".charCodeAt(0);
}
if (a >= "a" && a <= "z") a = a.toUpperCase();
let dec = 0;
if (a >= "A" && a <= "Z") {
if ("I" < a) dec++;
if ("L" < a) dec++;
if ("O" < a) dec++;
if ("U" < a) dec++;
return a.charCodeAt(0) - "A".charCodeAt(0) + 10 - dec;
}
throw new EncodingError();
}
export function encodeCrock(data: ArrayBuffer): string {
const dataBytes = new Uint8Array(data);
let sb = "";
const size = data.byteLength;
let bitBuf = 0;
let numBits = 0;
let pos = 0;
while (pos < size || numBits > 0) {
if (pos < size && numBits < 5) {
const d = dataBytes[pos++];
bitBuf = (bitBuf << 8) | d;
numBits += 8;
}
if (numBits < 5) {
// zero-padding
bitBuf = bitBuf << (5 - numBits);
numBits = 5;
}
const v = (bitBuf >>> (numBits - 5)) & 31;
sb += encTable[v];
numBits -= 5;
}
return sb;
}
export function decodeCrock(encoded: string): Uint8Array {
const size = encoded.length;
let bitpos = 0;
let bitbuf = 0;
let readPosition = 0;
const outLen = Math.floor((size * 5) / 8);
const out = new Uint8Array(outLen);
let outPos = 0;
while (readPosition < size || bitpos > 0) {
if (readPosition < size) {
const v = getValue(encoded[readPosition++]);
bitbuf = (bitbuf << 5) | v;
bitpos += 5;
}
while (bitpos >= 8) {
const d = (bitbuf >>> (bitpos - 8)) & 0xff;
out[outPos++] = d;
bitpos -= 8;
}
if (readPosition == size && bitpos > 0) {
bitbuf = (bitbuf << (8 - bitpos)) & 0xff;
bitpos = bitbuf == 0 ? 0 : 8;
}
}
return out;
}
export function eddsaGetPublic(eddsaPriv: Uint8Array): Uint8Array {
const pair = nacl.crypto_sign_keyPair_fromSeed(eddsaPriv);
return pair.publicKey;
}
export function ecdheGetPublic(ecdhePriv: Uint8Array): Uint8Array {
return nacl.scalarMult_base(ecdhePriv);
}
export function keyExchangeEddsaEcdhe(
eddsaPriv: Uint8Array,
ecdhePub: Uint8Array,
): Uint8Array {
const ph = nacl.hash(eddsaPriv);
const a = new Uint8Array(32);
for (let i = 0; i < 32; i++) {
a[i] = ph[i];
}
const x = nacl.scalarMult(a, ecdhePub);
return nacl.hash(x);
}
export function keyExchangeEcdheEddsa(
ecdhePriv: Uint8Array,
eddsaPub: Uint8Array,
): Uint8Array {
const curve25519Pub = nacl.sign_ed25519_pk_to_curve25519(eddsaPub);
const x = nacl.scalarMult(ecdhePriv, curve25519Pub);
return nacl.hash(x);
}
interface RsaPub {
N: bigint.BigInteger;
e: bigint.BigInteger;
}
/**
* KDF modulo a big integer.
*/
function kdfMod(
n: bigint.BigInteger,
ikm: Uint8Array,
salt: Uint8Array,
info: Uint8Array,
): bigint.BigInteger {
const nbits = n.bitLength().toJSNumber();
const buflen = Math.floor((nbits - 1) / 8 + 1);
const mask = (1 << (8 - (buflen * 8 - nbits))) - 1;
let counter = 0;
while (true) {
const ctx = new Uint8Array(info.byteLength + 2);
ctx.set(info, 0);
ctx[ctx.length - 2] = (counter >>> 8) & 0xff;
ctx[ctx.length - 1] = counter & 0xff;
const buf = kdf(buflen, ikm, salt, ctx);
const arr = Array.from(buf);
arr[0] = arr[0] & mask;
const r = bigint.fromArray(arr, 256, false);
if (r.lt(n)) {
return r;
}
counter++;
}
}
function csKdfMod(
n: bigint.BigInteger,
ikm: Uint8Array,
salt: Uint8Array,
info: Uint8Array,
): Uint8Array {
const nbits = n.bitLength().toJSNumber();
const buflen = Math.floor((nbits - 1) / 8 + 1);
const mask = (1 << (8 - (buflen * 8 - nbits))) - 1;
let counter = 0;
while (true) {
const ctx = new Uint8Array(info.byteLength + 2);
ctx.set(info, 0);
ctx[ctx.length - 2] = (counter >>> 8) & 0xff;
ctx[ctx.length - 1] = counter & 0xff;
const buf = kdf(buflen, ikm, salt, ctx);
const arr = Array.from(buf);
arr[0] = arr[0] & mask;
const r = bigint.fromArray(arr, 256, false);
if (r.lt(n)) {
return new Uint8Array(arr);
}
counter++;
}
}
// Newer versions of node have TextEncoder and TextDecoder as a global,
// just like modern browsers.
// In older versions of node or environments that do not have these
// globals, they must be polyfilled (by adding them to globa/globalThis)
// before stringToBytes or bytesToString is called the first time.
let encoder: any;
let decoder: any;
export function stringToBytes(s: string): Uint8Array {
if (!encoder) {
// @ts-ignore
encoder = new TextEncoder();
}
return encoder.encode(s);
}
export function bytesToString(b: Uint8Array): string {
if (!decoder) {
// @ts-ignore
decoder = new TextDecoder();
}
return decoder.decode(b);
}
function loadBigInt(arr: Uint8Array): bigint.BigInteger {
return bigint.fromArray(Array.from(arr), 256, false);
}
function rsaBlindingKeyDerive(
rsaPub: RsaPub,
bks: Uint8Array,
): bigint.BigInteger {
const salt = stringToBytes("Blinding KDF extractor HMAC key");
const info = stringToBytes("Blinding KDF");
return kdfMod(rsaPub.N, bks, salt, info);
}
/*
* Test for malicious RSA key.
*
* Assuming n is an RSA modulous and r is generated using a call to
* GNUNET_CRYPTO_kdf_mod_mpi, if gcd(r,n) != 1 then n must be a
* malicious RSA key designed to deanomize the user.
*
* @param r KDF result
* @param n RSA modulus of the public key
*/
function rsaGcdValidate(r: bigint.BigInteger, n: bigint.BigInteger): void {
const t = bigint.gcd(r, n);
if (!t.equals(bigint.one)) {
throw Error("malicious RSA public key");
}
}
function rsaFullDomainHash(hm: Uint8Array, rsaPub: RsaPub): bigint.BigInteger {
const info = stringToBytes("RSA-FDA FTpsW!");
const salt = rsaPubEncode(rsaPub);
const r = kdfMod(rsaPub.N, hm, salt, info);
rsaGcdValidate(r, rsaPub.N);
return r;
}
function rsaPubDecode(rsaPub: Uint8Array): RsaPub {
const modulusLength = (rsaPub[0] << 8) | rsaPub[1];
const exponentLength = (rsaPub[2] << 8) | rsaPub[3];
if (4 + exponentLength + modulusLength != rsaPub.length) {
throw Error("invalid RSA public key (format wrong)");
}
const modulus = rsaPub.slice(4, 4 + modulusLength);
const exponent = rsaPub.slice(
4 + modulusLength,
4 + modulusLength + exponentLength,
);
const res = {
N: loadBigInt(modulus),
e: loadBigInt(exponent),
};
return res;
}
function rsaPubEncode(rsaPub: RsaPub): Uint8Array {
const mb = rsaPub.N.toArray(256).value;
const eb = rsaPub.e.toArray(256).value;
const out = new Uint8Array(4 + mb.length + eb.length);
out[0] = (mb.length >>> 8) & 0xff;
out[1] = mb.length & 0xff;
out[2] = (eb.length >>> 8) & 0xff;
out[3] = eb.length & 0xff;
out.set(mb, 4);
out.set(eb, 4 + mb.length);
return out;
}
export function rsaBlind(
hm: Uint8Array,
bks: Uint8Array,
rsaPubEnc: Uint8Array,
): Uint8Array {
const rsaPub = rsaPubDecode(rsaPubEnc);
const data = rsaFullDomainHash(hm, rsaPub);
const r = rsaBlindingKeyDerive(rsaPub, bks);
const r_e = r.modPow(rsaPub.e, rsaPub.N);
const bm = r_e.multiply(data).mod(rsaPub.N);
return new Uint8Array(bm.toArray(256).value);
}
export function rsaUnblind(
sig: Uint8Array,
rsaPubEnc: Uint8Array,
bks: Uint8Array,
): Uint8Array {
const rsaPub = rsaPubDecode(rsaPubEnc);
const blinded_s = loadBigInt(sig);
const r = rsaBlindingKeyDerive(rsaPub, bks);
const r_inv = r.modInv(rsaPub.N);
const s = blinded_s.multiply(r_inv).mod(rsaPub.N);
return new Uint8Array(s.toArray(256).value);
}
export function rsaVerify(
hm: Uint8Array,
rsaSig: Uint8Array,
rsaPubEnc: Uint8Array,
): boolean {
const rsaPub = rsaPubDecode(rsaPubEnc);
const d = rsaFullDomainHash(hm, rsaPub);
const sig = loadBigInt(rsaSig);
const sig_e = sig.modPow(rsaPub.e, rsaPub.N);
return sig_e.equals(d);
}
export type CsSignature = {
s: Uint8Array;
rPub: Uint8Array;
};
export type CsBlindSignature = {
sBlind: Uint8Array;
rPubBlind: Uint8Array;
};
export type CsBlindingSecrets = {
alpha: [Uint8Array, Uint8Array];
beta: [Uint8Array, Uint8Array];
};
export function typedArrayConcat(chunks: Uint8Array[]): Uint8Array {
let payloadLen = 0;
for (const c of chunks) {
payloadLen += c.byteLength;
}
const buf = new ArrayBuffer(payloadLen);
const u8buf = new Uint8Array(buf);
let p = 0;
for (const c of chunks) {
u8buf.set(c, p);
p += c.byteLength;
}
return u8buf;
}
/**
* Map to scalar subgroup function
* perform clamping as described in RFC7748
* @param scalar
*/
function mtoSS(scalar: Uint8Array): Uint8Array {
scalar[0] &= 248;
scalar[31] &= 127;
scalar[31] |= 64;
return scalar;
}
/**
* The function returns the CS blinding secrets from a seed
* @param bseed seed to derive blinding secrets
* @returns blinding secrets
*/
export function deriveSecrets(bseed: Uint8Array): CsBlindingSecrets {
const outLen = 130;
const salt = stringToBytes("alphabeta");
const rndout = kdf(outLen, bseed, salt);
const secrets: CsBlindingSecrets = {
alpha: [mtoSS(rndout.slice(0, 32)), mtoSS(rndout.slice(64, 96))],
beta: [mtoSS(rndout.slice(32, 64)), mtoSS(rndout.slice(96, 128))],
};
return secrets;
}
/**
* Used for testing, simple scalar multiplication with base point of Ed25519
* @param s scalar
* @returns new point sG
*/
export async function scalarMultBase25519(s: Uint8Array): Promise<Uint8Array> {
return nacl.crypto_scalarmult_ed25519_base_noclamp(s);
}
/**
* calculation of the blinded public point R in CS
* @param csPub denomination publik key
* @param secrets client blinding secrets
* @param rPub public R received from /csr API
*/
export async function calcRBlind(
csPub: Uint8Array,
secrets: CsBlindingSecrets,
rPub: [Uint8Array, Uint8Array],
): Promise<[Uint8Array, Uint8Array]> {
const aG0 = nacl.crypto_scalarmult_ed25519_base_noclamp(secrets.alpha[0]);
const aG1 = nacl.crypto_scalarmult_ed25519_base_noclamp(secrets.alpha[1]);
const bDp0 = nacl.crypto_scalarmult_ed25519_noclamp(secrets.beta[0], csPub);
const bDp1 = nacl.crypto_scalarmult_ed25519_noclamp(secrets.beta[1], csPub);
const res0 = nacl.crypto_core_ed25519_add(aG0, bDp0);
const res1 = nacl.crypto_core_ed25519_add(aG1, bDp1);
return [
nacl.crypto_core_ed25519_add(rPub[0], res0),
nacl.crypto_core_ed25519_add(rPub[1], res1),
];
}
/**
* FDH function used in CS
* @param hm message hash
* @param rPub public R included in FDH
* @param csPub denomination public key as context
* @returns mapped Curve25519 scalar
*/
function csFDH(
hm: Uint8Array,
rPub: Uint8Array,
csPub: Uint8Array,
): Uint8Array {
const lMod = Array.from(
new Uint8Array([
0x10, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x14, 0xde, 0xf9, 0xde, 0xa2, 0xf7, 0x9c, 0xd6,
0x58, 0x12, 0x63, 0x1a, 0x5c, 0xf5, 0xd3, 0xed,
]),
);
const L = bigint.fromArray(lMod, 256, false);
const info = stringToBytes("Curve25519FDH");
const preshash = nacl.hash(typedArrayConcat([rPub, hm]));
return csKdfMod(L, preshash, csPub, info).reverse();
}
/**
* blinding seed derived from coin private key
* @param coinPriv private key of the corresponding coin
* @param rPub public R received from /csr API
* @returns blinding seed
*/
export function deriveBSeed(
coinPriv: Uint8Array,
rPub: [Uint8Array, Uint8Array],
): Uint8Array {
const outLen = 32;
const salt = stringToBytes("b-seed");
const ikm = typedArrayConcat([coinPriv, rPub[0], rPub[1]]);
return kdf(outLen, ikm, salt);
}
/**
* Derive withdraw nonce, used in /csr request
* Note: In withdraw protocol, the nonce is chosen randomly
* @param coinPriv coin private key
* @returns nonce
*/
export function deriveWithdrawNonce(coinPriv: Uint8Array): Uint8Array {
const outLen = 32;
const salt = stringToBytes("n");
return kdf(outLen, coinPriv, salt);
}
/**
* Blind operation for CS signatures, used after /csr call
* @param bseed blinding seed to derive blinding secrets
* @param rPub public R received from /csr
* @param csPub denomination public key
* @param hm message to blind
* @returns two blinded c
*/
export async function csBlind(
bseed: Uint8Array,
rPub: [Uint8Array, Uint8Array],
csPub: Uint8Array,
hm: Uint8Array,
): Promise<[Uint8Array, Uint8Array]> {
const secrets = deriveSecrets(bseed);
const rPubBlind = await calcRBlind(csPub, secrets, rPub);
const c_0 = csFDH(hm, rPubBlind[0], csPub);
const c_1 = csFDH(hm, rPubBlind[1], csPub);
return [
nacl.crypto_core_ed25519_scalar_add(c_0, secrets.beta[0]),
nacl.crypto_core_ed25519_scalar_add(c_1, secrets.beta[1]),
];
}
/**
* Unblind operation to unblind the signature
* @param bseed seed to derive secrets
* @param rPub public R received from /csr
* @param csPub denomination publick key
* @param b returned from exchange to select c
* @param csSig blinded signature
* @returns unblinded signature
*/
export async function csUnblind(
bseed: Uint8Array,
rPub: [Uint8Array, Uint8Array],
csPub: Uint8Array,
b: number,
csSig: CsBlindSignature,
): Promise<CsSignature> {
if (b != 0 && b != 1) {
throw new Error();
}
const secrets = deriveSecrets(bseed);
const rPubDash = (await calcRBlind(csPub, secrets, rPub))[b];
const sig: CsSignature = {
s: nacl.crypto_core_ed25519_scalar_add(csSig.sBlind, secrets.alpha[b]),
rPub: rPubDash,
};
return sig;
}
/**
* Verification algorithm for CS signatures
* @param hm message signed
* @param csSig unblinded signature
* @param csPub denomination publick key
* @returns true if valid, false if invalid
*/
export async function csVerify(
hm: Uint8Array,
csSig: CsSignature,
csPub: Uint8Array,
): Promise<boolean> {
const cDash = csFDH(hm, csSig.rPub, csPub);
const sG = nacl.crypto_scalarmult_ed25519_base_noclamp(csSig.s);
const cbDp = nacl.crypto_scalarmult_ed25519_noclamp(cDash, csPub);
const sGeq = nacl.crypto_core_ed25519_add(csSig.rPub, cbDp);
return nacl.verify(sG, sGeq);
}
export interface EddsaKeyPair {
eddsaPub: Uint8Array;
eddsaPriv: Uint8Array;
}
export interface EcdheKeyPair {
ecdhePub: Uint8Array;
ecdhePriv: Uint8Array;
}
export interface Edx25519Keypair {
edxPub: string;
edxPriv: string;
}
export function createEddsaKeyPair(): EddsaKeyPair {
const eddsaPriv = nacl.randomBytes(32);
const eddsaPub = eddsaGetPublic(eddsaPriv);
return { eddsaPriv, eddsaPub };
}
export function createEcdheKeyPair(): EcdheKeyPair {
const ecdhePriv = nacl.randomBytes(32);
const ecdhePub = ecdheGetPublic(ecdhePriv);
return { ecdhePriv, ecdhePub };
}
export function hash(d: Uint8Array): Uint8Array {
return nacl.hash(d);
}
/**
* Hash the input with SHA-512 and truncate the result
* to 32 bytes.
*/
export function hashTruncate32(d: Uint8Array): Uint8Array {
const sha512HashCode = nacl.hash(d);
return sha512HashCode.subarray(0, 32);
}
export function hashCoinEv(
coinEv: CoinEnvelope,
denomPubHash: HashCodeString,
): Uint8Array {
const hashContext = createHashContext();
hashContext.update(decodeCrock(denomPubHash));
hashCoinEvInner(coinEv, hashContext);
return hashContext.finish();
}
const logger = new Logger("talerCrypto.ts");
export function hashCoinEvInner(
coinEv: CoinEnvelope,
hashState: nacl.HashState,
): void {
const hashInputBuf = new ArrayBuffer(4);
const uint8ArrayBuf = new Uint8Array(hashInputBuf);
const dv = new DataView(hashInputBuf);
dv.setUint32(0, DenomKeyType.toIntTag(coinEv.cipher));
hashState.update(uint8ArrayBuf);
switch (coinEv.cipher) {
case DenomKeyType.Rsa:
hashState.update(decodeCrock(coinEv.rsa_blinded_planchet));
return;
default:
throw new Error();
}
}
export function hashCoinPub(
coinPub: CoinPublicKeyString,
ach?: HashCodeString,
): Uint8Array {
if (!ach) {
return hash(decodeCrock(coinPub));
}
return hash(typedArrayConcat([decodeCrock(coinPub), decodeCrock(ach)]));
}
/**
* Hash a denomination public key.
*/
export function hashDenomPub(pub: DenominationPubKey): Uint8Array {
if (pub.cipher === DenomKeyType.Rsa) {
const pubBuf = decodeCrock(pub.rsa_public_key);
const hashInputBuf = new ArrayBuffer(pubBuf.length + 4 + 4);
const uint8ArrayBuf = new Uint8Array(hashInputBuf);
const dv = new DataView(hashInputBuf);
dv.setUint32(0, pub.age_mask ?? 0);
dv.setUint32(4, DenomKeyType.toIntTag(pub.cipher));
uint8ArrayBuf.set(pubBuf, 8);
return nacl.hash(uint8ArrayBuf);
} else if (pub.cipher === DenomKeyType.ClauseSchnorr) {
const pubBuf = decodeCrock(pub.cs_public_key);
const hashInputBuf = new ArrayBuffer(pubBuf.length + 4 + 4);
const uint8ArrayBuf = new Uint8Array(hashInputBuf);
const dv = new DataView(hashInputBuf);
dv.setUint32(0, pub.age_mask ?? 0);
dv.setUint32(4, DenomKeyType.toIntTag(pub.cipher));
uint8ArrayBuf.set(pubBuf, 8);
return nacl.hash(uint8ArrayBuf);
} else {
throw Error(
`unsupported cipher (${(pub as DenominationPubKey).cipher
}), unable to hash`,
);
}
}
export function eddsaSign(msg: Uint8Array, eddsaPriv: Uint8Array): Uint8Array {
const pair = nacl.crypto_sign_keyPair_fromSeed(eddsaPriv);
return nacl.sign_detached(msg, pair.secretKey);
}
export function eddsaVerify(
msg: Uint8Array,
sig: Uint8Array,
eddsaPub: Uint8Array,
): boolean {
return nacl.sign_detached_verify(msg, sig, eddsaPub);
}
export function createHashContext(): nacl.HashState {
return new nacl.HashState();
}
export interface FreshCoin {
coinPub: Uint8Array;
coinPriv: Uint8Array;
bks: Uint8Array;
}
export function bufferForUint32(n: number): Uint8Array {
const arrBuf = new ArrayBuffer(4);
const buf = new Uint8Array(arrBuf);
const dv = new DataView(arrBuf);
dv.setUint32(0, n);
return buf;
}
export function bufferForUint8(n: number): Uint8Array {
const arrBuf = new ArrayBuffer(1);
const buf = new Uint8Array(arrBuf);
const dv = new DataView(arrBuf);
dv.setUint8(0, n);
return buf;
}
export function setupTipPlanchet(
secretSeed: Uint8Array,
coinNumber: number,
): FreshCoin {
const info = stringToBytes("taler-tip-coin-derivation");
const saltArrBuf = new ArrayBuffer(4);
const salt = new Uint8Array(saltArrBuf);
const saltDataView = new DataView(saltArrBuf);
saltDataView.setUint32(0, coinNumber);
const out = kdf(64, secretSeed, salt, info);
const coinPriv = out.slice(0, 32);
const bks = out.slice(32, 64);
return {
bks,
coinPriv,
coinPub: eddsaGetPublic(coinPriv),
};
}
/**
*
* @param paytoUri
* @param salt 16-byte salt
* @returns
*/
export function hashWire(paytoUri: string, salt: string): string {
const r = kdf(
64,
stringToBytes(paytoUri + "\0"),
decodeCrock(salt),
stringToBytes("merchant-wire-signature"),
);
return encodeCrock(r);
}
export enum TalerSignaturePurpose {
MERCHANT_TRACK_TRANSACTION = 1103,
WALLET_RESERVE_WITHDRAW = 1200,
WALLET_COIN_DEPOSIT = 1201,
MASTER_DENOMINATION_KEY_VALIDITY = 1025,
MASTER_WIRE_FEES = 1028,
MASTER_WIRE_DETAILS = 1030,
WALLET_COIN_MELT = 1202,
TEST = 4242,
MERCHANT_PAYMENT_OK = 1104,
MERCHANT_CONTRACT = 1101,
WALLET_COIN_RECOUP = 1203,
WALLET_COIN_LINK = 1204,
WALLET_COIN_RECOUP_REFRESH = 1206,
WALLET_AGE_ATTESTATION = 1207,
EXCHANGE_CONFIRM_RECOUP = 1039,
EXCHANGE_CONFIRM_RECOUP_REFRESH = 1041,
ANASTASIS_POLICY_UPLOAD = 1400,
ANASTASIS_POLICY_DOWNLOAD = 1401,
SYNC_BACKUP_UPLOAD = 1450,
}
export class SignaturePurposeBuilder {
private chunks: Uint8Array[] = [];
constructor(private purposeNum: number) { }
put(bytes: Uint8Array): SignaturePurposeBuilder {
this.chunks.push(Uint8Array.from(bytes));
return this;
}
build(): Uint8Array {
let payloadLen = 0;
for (const c of this.chunks) {
payloadLen += c.byteLength;
}
const buf = new ArrayBuffer(4 + 4 + payloadLen);
const u8buf = new Uint8Array(buf);
let p = 8;
for (const c of this.chunks) {
u8buf.set(c, p);
p += c.byteLength;
}
const dvbuf = new DataView(buf);
dvbuf.setUint32(0, payloadLen + 4 + 4);
dvbuf.setUint32(4, this.purposeNum);
return u8buf;
}
}
export function buildSigPS(purposeNum: number): SignaturePurposeBuilder {
return new SignaturePurposeBuilder(purposeNum);
}
export type Flavor<T, FlavorT extends string> = T & {
_flavor?: `taler.${FlavorT}`;
};
export type FlavorP<T, FlavorT extends string, S extends number> = T & {
_flavor?: `taler.${FlavorT}`;
_size?: S;
};
export type OpaqueData = Flavor<string, "OpaqueData">;
export type Edx25519PublicKey = FlavorP<string, "Edx25519PublicKey", 32>;
export type Edx25519PrivateKey = FlavorP<string, "Edx25519PrivateKey", 64>;
export type Edx25519Signature = FlavorP<string, "Edx25519Signature", 64>;
/**
* Convert a big integer to a fixed-size, little-endian array.
*/
export function bigintToNaclArr(
x: bigint.BigInteger,
size: number,
): Uint8Array {
const byteArr = new Uint8Array(size);
const arr = x.toArray(256).value.reverse();
byteArr.set(arr, 0);
return byteArr;
}
export function bigintFromNaclArr(arr: Uint8Array): bigint.BigInteger {
let rev = new Uint8Array(arr);
rev = rev.reverse();
return bigint.fromArray(Array.from(rev), 256, false);
}
export namespace Edx25519 {
const revL = [
0xed, 0xd3, 0xf5, 0x5c, 0x1a, 0x63, 0x12, 0x58, 0xd6, 0x9c, 0xf7, 0xa2,
0xde, 0xf9, 0xde, 0x14, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x10,
];
const L = bigint.fromArray(revL.reverse(), 256, false);
export async function keyCreateFromSeed(
seed: OpaqueData,
): Promise<Edx25519PrivateKey> {
return encodeCrock(
nacl.crypto_edx25519_private_key_create_from_seed(decodeCrock(seed)),
);
}
export async function keyCreate(): Promise<Edx25519PrivateKey> {
return encodeCrock(nacl.crypto_edx25519_private_key_create());
}
export async function getPublic(
priv: Edx25519PrivateKey,
): Promise<Edx25519PublicKey> {
return encodeCrock(nacl.crypto_edx25519_get_public(decodeCrock(priv)));
}
export function sign(
msg: OpaqueData,
key: Edx25519PrivateKey,
): Promise<Edx25519Signature> {
throw Error("not implemented");
}
async function deriveFactor(
pub: Edx25519PublicKey,
seed: OpaqueData,
): Promise<OpaqueData> {
const res = kdfKw({
outputLength: 64,
salt: decodeCrock(seed),
ikm: decodeCrock(pub),
info: stringToBytes("edx25519-derivation"),
});
return encodeCrock(res);
}
export async function privateKeyDerive(
priv: Edx25519PrivateKey,
seed: OpaqueData,
): Promise<Edx25519PrivateKey> {
const pub = await getPublic(priv);
const privDec = decodeCrock(priv);
const a = bigintFromNaclArr(privDec.subarray(0, 32));
const factorEnc = await deriveFactor(pub, seed);
const factorModL = bigintFromNaclArr(decodeCrock(factorEnc)).mod(L);
const aPrime = a.divide(8).multiply(factorModL).mod(L).multiply(8).mod(L);
const bPrime = nacl
.hash(
typedArrayConcat([privDec.subarray(32, 64), decodeCrock(factorEnc)]),
)
.subarray(0, 32);
const newPriv = encodeCrock(
typedArrayConcat([bigintToNaclArr(aPrime, 32), bPrime]),
);
return newPriv;
}
export async function publicKeyDerive(
pub: Edx25519PublicKey,
seed: OpaqueData,
): Promise<Edx25519PublicKey> {
const factorEnc = await deriveFactor(pub, seed);
const factorReduced = nacl.crypto_core_ed25519_scalar_reduce(
decodeCrock(factorEnc),
);
const res = nacl.crypto_scalarmult_ed25519_noclamp(
factorReduced,
decodeCrock(pub),
);
return encodeCrock(res);
}
}
export interface AgeCommitment {
mask: number;
/**
* Public keys, one for each age group specified in the age mask.
*/
publicKeys: Edx25519PublicKey[];
}
export interface AgeProof {
/**
* Private keys. Typically smaller than the number of public keys,
* because we drop private keys from age groups that are restricted.
*/
privateKeys: Edx25519PrivateKey[];
}
export interface AgeCommitmentProof {
commitment: AgeCommitment;
proof: AgeProof;
}
function invariant(cond: boolean): asserts cond {
if (!cond) {
throw Error("invariant failed");
}
}
export namespace AgeRestriction {
export function hashCommitment(ac: AgeCommitment): HashCodeString {
const hc = new nacl.HashState();
for (const pub of ac.publicKeys) {
hc.update(decodeCrock(pub));
}
return encodeCrock(hc.finish().subarray(0, 32));
}
export function countAgeGroups(mask: number): number {
let count = 0;
let m = mask;
while (m > 0) {
count += m & 1;
m = m >> 1;
}
return count;
}
export function getAgeGroupIndex(mask: number, age: number): number {
invariant((mask & 1) === 1);
let i = 0;
let m = mask;
let a = age;
while (m > 0) {
if (a <= 0) {
break;
}
m = m >> 1;
i += m & 1;
a--;
}
return i;
}
export function ageGroupSpecToMask(ageGroupSpec: string): number {
throw Error("not implemented");
}
export async function restrictionCommit(
ageMask: number,
age: number,
): Promise<AgeCommitmentProof> {
invariant((ageMask & 1) === 1);
const numPubs = countAgeGroups(ageMask) - 1;
const numPrivs = getAgeGroupIndex(ageMask, age);
const pubs: Edx25519PublicKey[] = [];
const privs: Edx25519PrivateKey[] = [];
for (let i = 0; i < numPubs; i++) {
const priv = await Edx25519.keyCreate();
const pub = await Edx25519.getPublic(priv);
pubs.push(pub);
if (i < numPrivs) {
privs.push(priv);
}
}
return {
commitment: {
mask: ageMask,
publicKeys: pubs,
},
proof: {
privateKeys: privs,
},
};
}
/**
* Check that c1 = c2*salt
*/
export async function commitCompare(
c1: AgeCommitment,
c2: AgeCommitment,
salt: OpaqueData,
): Promise<boolean> {
if (c1.publicKeys.length != c2.publicKeys.length) {
return false;
}
for (let i = 0; i < c1.publicKeys.length; i++) {
const k1 = c1.publicKeys[i];
const k2 = await Edx25519.publicKeyDerive(c2.publicKeys[i], salt);
if (k1 != k2) {
return false;
}
}
return true;
}
export async function commitmentDerive(
commitmentProof: AgeCommitmentProof,
salt: OpaqueData,
): Promise<AgeCommitmentProof> {
const newPrivs: Edx25519PrivateKey[] = [];
const newPubs: Edx25519PublicKey[] = [];
for (const oldPub of commitmentProof.commitment.publicKeys) {
newPubs.push(await Edx25519.publicKeyDerive(oldPub, salt));
}
for (const oldPriv of commitmentProof.proof.privateKeys) {
newPrivs.push(await Edx25519.privateKeyDerive(oldPriv, salt));
}
return {
commitment: {
mask: commitmentProof.commitment.mask,
publicKeys: newPubs,
},
proof: {
privateKeys: newPrivs,
},
};
}
export function commitmentAttest(
commitmentProof: AgeCommitmentProof,
age: number,
): Edx25519Signature {
const d = buildSigPS(TalerSignaturePurpose.WALLET_AGE_ATTESTATION)
.put(bufferForUint32(commitmentProof.commitment.mask))
.put(bufferForUint32(age))
.build();
const group = getAgeGroupIndex(commitmentProof.commitment.mask, age);
if (group === 0) {
// No attestation required.
return encodeCrock(new Uint8Array(64));
}
const priv = commitmentProof.proof.privateKeys[group - 1];
const pub = commitmentProof.commitment.publicKeys[group - 1];
const sig = nacl.crypto_edx25519_sign_detached(
d,
decodeCrock(priv),
decodeCrock(pub),
);
return encodeCrock(sig);
}
export function commitmentVerify(
commitment: AgeCommitment,
sig: string,
age: number,
): boolean {
const d = buildSigPS(TalerSignaturePurpose.WALLET_AGE_ATTESTATION)
.put(bufferForUint32(commitment.mask))
.put(bufferForUint32(age))
.build();
const group = getAgeGroupIndex(commitment.mask, age);
if (group === 0) {
// No attestation required.
return true;
}
const pub = commitment.publicKeys[group - 1];
return nacl.crypto_edx25519_sign_detached_verify(
d,
decodeCrock(sig),
decodeCrock(pub),
);
}
}
|