]> git.ipfire.org Git - thirdparty/openssl.git/blob - crypto/ec/ecp_nistz256.c
projects / thirdparty / openssl.git / blob
? search:
summary | shortlog | log | commit | commitdiff | tree
blame | history | raw | HEAD
Copyright consolidation 05/10
[thirdparty/openssl.git] / crypto / ec / ecp_nistz256.c
1 /*
2 * Copyright 2014-2016 The OpenSSL Project Authors. All Rights Reserved.
3 *
4 * Licensed under the OpenSSL license (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
8 */
9
10 /******************************************************************************
11 * *
12 * Copyright 2014 Intel Corporation *
13 * *
14 * Licensed under the Apache License, Version 2.0 (the "License"); *
15 * you may not use this file except in compliance with the License. *
16 * You may obtain a copy of the License at *
17 * *
18 * http://www.apache.org/licenses/LICENSE-2.0 *
19 * *
20 * Unless required by applicable law or agreed to in writing, software *
21 * distributed under the License is distributed on an "AS IS" BASIS, *
22 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. *
23 * See the License for the specific language governing permissions and *
24 * limitations under the License. *
25 * *
26 ******************************************************************************
27 * *
28 * Developers and authors: *
29 * Shay Gueron (1, 2), and Vlad Krasnov (1) *
30 * (1) Intel Corporation, Israel Development Center *
31 * (2) University of Haifa *
32 * Reference: *
33 * S.Gueron and V.Krasnov, "Fast Prime Field Elliptic Curve Cryptography with *
34 * 256 Bit Primes" *
35 * *
36 ******************************************************************************/
37
38 #include <string.h>
39
40 #include "internal/cryptlib.h"
41 #include "internal/bn_int.h"
42 #include "ec_lcl.h"
43
44 #if BN_BITS2 != 64
45 # define TOBN(hi,lo) lo,hi
46 #else
47 # define TOBN(hi,lo) ((BN_ULONG)hi<<32|lo)
48 #endif
49
50 #if defined(__GNUC__)
51 # define ALIGN32 __attribute((aligned(32)))
52 #elif defined(_MSC_VER)
53 # define ALIGN32 __declspec(align(32))
54 #else
55 # define ALIGN32
56 #endif
57
58 #define ALIGNPTR(p,N) ((unsigned char *)p+N-(size_t)p%N)
59 #define P256_LIMBS (256/BN_BITS2)
60
61 typedef unsigned short u16;
62
63 typedef struct {
64 BN_ULONG X[P256_LIMBS];
65 BN_ULONG Y[P256_LIMBS];
66 BN_ULONG Z[P256_LIMBS];
67 } P256_POINT;
68
69 typedef struct {
70 BN_ULONG X[P256_LIMBS];
71 BN_ULONG Y[P256_LIMBS];
72 } P256_POINT_AFFINE;
73
74 typedef P256_POINT_AFFINE PRECOMP256_ROW[64];
75
76 /* structure for precomputed multiples of the generator */
77 struct nistz256_pre_comp_st {
78 const EC_GROUP *group; /* Parent EC_GROUP object */
79 size_t w; /* Window size */
80 /*
81 * Constant time access to the X and Y coordinates of the pre-computed,
82 * generator multiplies, in the Montgomery domain. Pre-calculated
83 * multiplies are stored in affine form.
84 */
85 PRECOMP256_ROW *precomp;
86 void *precomp_storage;
87 int references;
88 CRYPTO_RWLOCK *lock;
89 };
90
91 /* Functions implemented in assembly */
92 /* Modular mul by 2: res = 2*a mod P */
93 void ecp_nistz256_mul_by_2(BN_ULONG res[P256_LIMBS],
94 const BN_ULONG a[P256_LIMBS]);
95 /* Modular div by 2: res = a/2 mod P */
96 void ecp_nistz256_div_by_2(BN_ULONG res[P256_LIMBS],
97 const BN_ULONG a[P256_LIMBS]);
98 /* Modular mul by 3: res = 3*a mod P */
99 void ecp_nistz256_mul_by_3(BN_ULONG res[P256_LIMBS],
100 const BN_ULONG a[P256_LIMBS]);
101 /* Modular add: res = a+b mod P */
102 void ecp_nistz256_add(BN_ULONG res[P256_LIMBS],
103 const BN_ULONG a[P256_LIMBS],
104 const BN_ULONG b[P256_LIMBS]);
105 /* Modular sub: res = a-b mod P */
106 void ecp_nistz256_sub(BN_ULONG res[P256_LIMBS],
107 const BN_ULONG a[P256_LIMBS],
108 const BN_ULONG b[P256_LIMBS]);
109 /* Modular neg: res = -a mod P */
110 void ecp_nistz256_neg(BN_ULONG res[P256_LIMBS], const BN_ULONG a[P256_LIMBS]);
111 /* Montgomery mul: res = a*b*2^-256 mod P */
112 void ecp_nistz256_mul_mont(BN_ULONG res[P256_LIMBS],
113 const BN_ULONG a[P256_LIMBS],
114 const BN_ULONG b[P256_LIMBS]);
115 /* Montgomery sqr: res = a*a*2^-256 mod P */
116 void ecp_nistz256_sqr_mont(BN_ULONG res[P256_LIMBS],
117 const BN_ULONG a[P256_LIMBS]);
118 /* Convert a number from Montgomery domain, by multiplying with 1 */
119 void ecp_nistz256_from_mont(BN_ULONG res[P256_LIMBS],
120 const BN_ULONG in[P256_LIMBS]);
121 /* Convert a number to Montgomery domain, by multiplying with 2^512 mod P*/
122 void ecp_nistz256_to_mont(BN_ULONG res[P256_LIMBS],
123 const BN_ULONG in[P256_LIMBS]);
124 /* Functions that perform constant time access to the precomputed tables */
125 void ecp_nistz256_scatter_w5(P256_POINT *val,
126 const P256_POINT *in_t, int idx);
127 void ecp_nistz256_gather_w5(P256_POINT *val,
128 const P256_POINT *in_t, int idx);
129 void ecp_nistz256_scatter_w7(P256_POINT_AFFINE *val,
130 const P256_POINT_AFFINE *in_t, int idx);
131 void ecp_nistz256_gather_w7(P256_POINT_AFFINE *val,
132 const P256_POINT_AFFINE *in_t, int idx);
133
134 /* One converted into the Montgomery domain */
135 static const BN_ULONG ONE[P256_LIMBS] = {
136 TOBN(0x00000000, 0x00000001), TOBN(0xffffffff, 0x00000000),
137 TOBN(0xffffffff, 0xffffffff), TOBN(0x00000000, 0xfffffffe)
138 };
139
140 static NISTZ256_PRE_COMP *ecp_nistz256_pre_comp_new(const EC_GROUP *group);
141
142 /* Precomputed tables for the default generator */
143 extern const PRECOMP256_ROW ecp_nistz256_precomputed[37];
144
145 /* Recode window to a signed digit, see ecp_nistputil.c for details */
146 static unsigned int _booth_recode_w5(unsigned int in)
147 {
148 unsigned int s, d;
149
150 s = ~((in >> 5) - 1);
151 d = (1 << 6) - in - 1;
152 d = (d & s) | (in & ~s);
153 d = (d >> 1) + (d & 1);
154
155 return (d << 1) + (s & 1);
156 }
157
158 static unsigned int _booth_recode_w7(unsigned int in)
159 {
160 unsigned int s, d;
161
162 s = ~((in >> 7) - 1);
163 d = (1 << 8) - in - 1;
164 d = (d & s) | (in & ~s);
165 d = (d >> 1) + (d & 1);
166
167 return (d << 1) + (s & 1);
168 }
169
170 static void copy_conditional(BN_ULONG dst[P256_LIMBS],
171 const BN_ULONG src[P256_LIMBS], BN_ULONG move)
172 {
173 BN_ULONG mask1 = 0-move;
174 BN_ULONG mask2 = ~mask1;
175
176 dst[0] = (src[0] & mask1) ^ (dst[0] & mask2);
177 dst[1] = (src[1] & mask1) ^ (dst[1] & mask2);
178 dst[2] = (src[2] & mask1) ^ (dst[2] & mask2);
179 dst[3] = (src[3] & mask1) ^ (dst[3] & mask2);
180 if (P256_LIMBS == 8) {
181 dst[4] = (src[4] & mask1) ^ (dst[4] & mask2);
182 dst[5] = (src[5] & mask1) ^ (dst[5] & mask2);
183 dst[6] = (src[6] & mask1) ^ (dst[6] & mask2);
184 dst[7] = (src[7] & mask1) ^ (dst[7] & mask2);
185 }
186 }
187
188 static BN_ULONG is_zero(BN_ULONG in)
189 {
190 in |= (0 - in);
191 in = ~in;
192 in >>= BN_BITS2 - 1;
193 return in;
194 }
195
196 static BN_ULONG is_equal(const BN_ULONG a[P256_LIMBS],
197 const BN_ULONG b[P256_LIMBS])
198 {
199 BN_ULONG res;
200
201 res = a[0] ^ b[0];
202 res |= a[1] ^ b[1];
203 res |= a[2] ^ b[2];
204 res |= a[3] ^ b[3];
205 if (P256_LIMBS == 8) {
206 res |= a[4] ^ b[4];
207 res |= a[5] ^ b[5];
208 res |= a[6] ^ b[6];
209 res |= a[7] ^ b[7];
210 }
211
212 return is_zero(res);
213 }
214
215 static BN_ULONG is_one(const BN_ULONG a[P256_LIMBS])
216 {
217 BN_ULONG res;
218
219 res = a[0] ^ ONE[0];
220 res |= a[1] ^ ONE[1];
221 res |= a[2] ^ ONE[2];
222 res |= a[3] ^ ONE[3];
223 if (P256_LIMBS == 8) {
224 res |= a[4] ^ ONE[4];
225 res |= a[5] ^ ONE[5];
226 res |= a[6] ^ ONE[6];
227 }
228
229 return is_zero(res);
230 }
231
232 #ifndef ECP_NISTZ256_REFERENCE_IMPLEMENTATION
233 void ecp_nistz256_point_double(P256_POINT *r, const P256_POINT *a);
234 void ecp_nistz256_point_add(P256_POINT *r,
235 const P256_POINT *a, const P256_POINT *b);
236 void ecp_nistz256_point_add_affine(P256_POINT *r,
237 const P256_POINT *a,
238 const P256_POINT_AFFINE *b);
239 #else
240 /* Point double: r = 2*a */
241 static void ecp_nistz256_point_double(P256_POINT *r, const P256_POINT *a)
242 {
243 BN_ULONG S[P256_LIMBS];
244 BN_ULONG M[P256_LIMBS];
245 BN_ULONG Zsqr[P256_LIMBS];
246 BN_ULONG tmp0[P256_LIMBS];
247
248 const BN_ULONG *in_x = a->X;
249 const BN_ULONG *in_y = a->Y;
250 const BN_ULONG *in_z = a->Z;
251
252 BN_ULONG *res_x = r->X;
253 BN_ULONG *res_y = r->Y;
254 BN_ULONG *res_z = r->Z;
255
256 ecp_nistz256_mul_by_2(S, in_y);
257
258 ecp_nistz256_sqr_mont(Zsqr, in_z);
259
260 ecp_nistz256_sqr_mont(S, S);
261
262 ecp_nistz256_mul_mont(res_z, in_z, in_y);
263 ecp_nistz256_mul_by_2(res_z, res_z);
264
265 ecp_nistz256_add(M, in_x, Zsqr);
266 ecp_nistz256_sub(Zsqr, in_x, Zsqr);
267
268 ecp_nistz256_sqr_mont(res_y, S);
269 ecp_nistz256_div_by_2(res_y, res_y);
270
271 ecp_nistz256_mul_mont(M, M, Zsqr);
272 ecp_nistz256_mul_by_3(M, M);
273
274 ecp_nistz256_mul_mont(S, S, in_x);
275 ecp_nistz256_mul_by_2(tmp0, S);
276
277 ecp_nistz256_sqr_mont(res_x, M);
278
279 ecp_nistz256_sub(res_x, res_x, tmp0);
280 ecp_nistz256_sub(S, S, res_x);
281
282 ecp_nistz256_mul_mont(S, S, M);
283 ecp_nistz256_sub(res_y, S, res_y);
284 }
285
286 /* Point addition: r = a+b */
287 static void ecp_nistz256_point_add(P256_POINT *r,
288 const P256_POINT *a, const P256_POINT *b)
289 {
290 BN_ULONG U2[P256_LIMBS], S2[P256_LIMBS];
291 BN_ULONG U1[P256_LIMBS], S1[P256_LIMBS];
292 BN_ULONG Z1sqr[P256_LIMBS];
293 BN_ULONG Z2sqr[P256_LIMBS];
294 BN_ULONG H[P256_LIMBS], R[P256_LIMBS];
295 BN_ULONG Hsqr[P256_LIMBS];
296 BN_ULONG Rsqr[P256_LIMBS];
297 BN_ULONG Hcub[P256_LIMBS];
298
299 BN_ULONG res_x[P256_LIMBS];
300 BN_ULONG res_y[P256_LIMBS];
301 BN_ULONG res_z[P256_LIMBS];
302
303 BN_ULONG in1infty, in2infty;
304
305 const BN_ULONG *in1_x = a->X;
306 const BN_ULONG *in1_y = a->Y;
307 const BN_ULONG *in1_z = a->Z;
308
309 const BN_ULONG *in2_x = b->X;
310 const BN_ULONG *in2_y = b->Y;
311 const BN_ULONG *in2_z = b->Z;
312
313 /* We encode infinity as (0,0), which is not on the curve,
314 * so it is OK. */
315 in1infty = (in1_x[0] | in1_x[1] | in1_x[2] | in1_x[3] |
316 in1_y[0] | in1_y[1] | in1_y[2] | in1_y[3]);
317 if (P256_LIMBS == 8)
318 in1infty |= (in1_x[4] | in1_x[5] | in1_x[6] | in1_x[7] |
319 in1_y[4] | in1_y[5] | in1_y[6] | in1_y[7]);
320
321 in2infty = (in2_x[0] | in2_x[1] | in2_x[2] | in2_x[3] |
322 in2_y[0] | in2_y[1] | in2_y[2] | in2_y[3]);
323 if (P256_LIMBS == 8)
324 in2infty |= (in2_x[4] | in2_x[5] | in2_x[6] | in2_x[7] |
325 in2_y[4] | in2_y[5] | in2_y[6] | in2_y[7]);
326
327 in1infty = is_zero(in1infty);
328 in2infty = is_zero(in2infty);
329
330 ecp_nistz256_sqr_mont(Z2sqr, in2_z); /* Z2^2 */
331 ecp_nistz256_sqr_mont(Z1sqr, in1_z); /* Z1^2 */
332
333 ecp_nistz256_mul_mont(S1, Z2sqr, in2_z); /* S1 = Z2^3 */
334 ecp_nistz256_mul_mont(S2, Z1sqr, in1_z); /* S2 = Z1^3 */
335
336 ecp_nistz256_mul_mont(S1, S1, in1_y); /* S1 = Y1*Z2^3 */
337 ecp_nistz256_mul_mont(S2, S2, in2_y); /* S2 = Y2*Z1^3 */
338 ecp_nistz256_sub(R, S2, S1); /* R = S2 - S1 */
339
340 ecp_nistz256_mul_mont(U1, in1_x, Z2sqr); /* U1 = X1*Z2^2 */
341 ecp_nistz256_mul_mont(U2, in2_x, Z1sqr); /* U2 = X2*Z1^2 */
342 ecp_nistz256_sub(H, U2, U1); /* H = U2 - U1 */
343
344 /*
345 * This should not happen during sign/ecdh, so no constant time violation
346 */
347 if (is_equal(U1, U2) && !in1infty && !in2infty) {
348 if (is_equal(S1, S2)) {
349 ecp_nistz256_point_double(r, a);
350 return;
351 } else {
352 memset(r, 0, sizeof(*r));
353 return;
354 }
355 }
356
357 ecp_nistz256_sqr_mont(Rsqr, R); /* R^2 */
358 ecp_nistz256_mul_mont(res_z, H, in1_z); /* Z3 = H*Z1*Z2 */
359 ecp_nistz256_sqr_mont(Hsqr, H); /* H^2 */
360 ecp_nistz256_mul_mont(res_z, res_z, in2_z); /* Z3 = H*Z1*Z2 */
361 ecp_nistz256_mul_mont(Hcub, Hsqr, H); /* H^3 */
362
363 ecp_nistz256_mul_mont(U2, U1, Hsqr); /* U1*H^2 */
364 ecp_nistz256_mul_by_2(Hsqr, U2); /* 2*U1*H^2 */
365
366 ecp_nistz256_sub(res_x, Rsqr, Hsqr);
367 ecp_nistz256_sub(res_x, res_x, Hcub);
368
369 ecp_nistz256_sub(res_y, U2, res_x);
370
371 ecp_nistz256_mul_mont(S2, S1, Hcub);
372 ecp_nistz256_mul_mont(res_y, R, res_y);
373 ecp_nistz256_sub(res_y, res_y, S2);
374
375 copy_conditional(res_x, in2_x, in1infty);
376 copy_conditional(res_y, in2_y, in1infty);
377 copy_conditional(res_z, in2_z, in1infty);
378
379 copy_conditional(res_x, in1_x, in2infty);
380 copy_conditional(res_y, in1_y, in2infty);
381 copy_conditional(res_z, in1_z, in2infty);
382
383 memcpy(r->X, res_x, sizeof(res_x));
384 memcpy(r->Y, res_y, sizeof(res_y));
385 memcpy(r->Z, res_z, sizeof(res_z));
386 }
387
388 /* Point addition when b is known to be affine: r = a+b */
389 static void ecp_nistz256_point_add_affine(P256_POINT *r,
390 const P256_POINT *a,
391 const P256_POINT_AFFINE *b)
392 {
393 BN_ULONG U2[P256_LIMBS], S2[P256_LIMBS];
394 BN_ULONG Z1sqr[P256_LIMBS];
395 BN_ULONG H[P256_LIMBS], R[P256_LIMBS];
396 BN_ULONG Hsqr[P256_LIMBS];
397 BN_ULONG Rsqr[P256_LIMBS];
398 BN_ULONG Hcub[P256_LIMBS];
399
400 BN_ULONG res_x[P256_LIMBS];
401 BN_ULONG res_y[P256_LIMBS];
402 BN_ULONG res_z[P256_LIMBS];
403
404 BN_ULONG in1infty, in2infty;
405
406 const BN_ULONG *in1_x = a->X;
407 const BN_ULONG *in1_y = a->Y;
408 const BN_ULONG *in1_z = a->Z;
409
410 const BN_ULONG *in2_x = b->X;
411 const BN_ULONG *in2_y = b->Y;
412
413 /*
414 * In affine representation we encode infty as (0,0), which is not on the
415 * curve, so it is OK
416 */
417 in1infty = (in1_x[0] | in1_x[1] | in1_x[2] | in1_x[3] |
418 in1_y[0] | in1_y[1] | in1_y[2] | in1_y[3]);
419 if (P256_LIMBS == 8)
420 in1infty |= (in1_x[4] | in1_x[5] | in1_x[6] | in1_x[7] |
421 in1_y[4] | in1_y[5] | in1_y[6] | in1_y[7]);
422
423 in2infty = (in2_x[0] | in2_x[1] | in2_x[2] | in2_x[3] |
424 in2_y[0] | in2_y[1] | in2_y[2] | in2_y[3]);
425 if (P256_LIMBS == 8)
426 in2infty |= (in2_x[4] | in2_x[5] | in2_x[6] | in2_x[7] |
427 in2_y[4] | in2_y[5] | in2_y[6] | in2_y[7]);
428
429 in1infty = is_zero(in1infty);
430 in2infty = is_zero(in2infty);
431
432 ecp_nistz256_sqr_mont(Z1sqr, in1_z); /* Z1^2 */
433
434 ecp_nistz256_mul_mont(U2, in2_x, Z1sqr); /* U2 = X2*Z1^2 */
435 ecp_nistz256_sub(H, U2, in1_x); /* H = U2 - U1 */
436
437 ecp_nistz256_mul_mont(S2, Z1sqr, in1_z); /* S2 = Z1^3 */
438
439 ecp_nistz256_mul_mont(res_z, H, in1_z); /* Z3 = H*Z1*Z2 */
440
441 ecp_nistz256_mul_mont(S2, S2, in2_y); /* S2 = Y2*Z1^3 */
442 ecp_nistz256_sub(R, S2, in1_y); /* R = S2 - S1 */
443
444 ecp_nistz256_sqr_mont(Hsqr, H); /* H^2 */
445 ecp_nistz256_sqr_mont(Rsqr, R); /* R^2 */
446 ecp_nistz256_mul_mont(Hcub, Hsqr, H); /* H^3 */
447
448 ecp_nistz256_mul_mont(U2, in1_x, Hsqr); /* U1*H^2 */
449 ecp_nistz256_mul_by_2(Hsqr, U2); /* 2*U1*H^2 */
450
451 ecp_nistz256_sub(res_x, Rsqr, Hsqr);
452 ecp_nistz256_sub(res_x, res_x, Hcub);
453 ecp_nistz256_sub(H, U2, res_x);
454
455 ecp_nistz256_mul_mont(S2, in1_y, Hcub);
456 ecp_nistz256_mul_mont(H, H, R);
457 ecp_nistz256_sub(res_y, H, S2);
458
459 copy_conditional(res_x, in2_x, in1infty);
460 copy_conditional(res_x, in1_x, in2infty);
461
462 copy_conditional(res_y, in2_y, in1infty);
463 copy_conditional(res_y, in1_y, in2infty);
464
465 copy_conditional(res_z, ONE, in1infty);
466 copy_conditional(res_z, in1_z, in2infty);
467
468 memcpy(r->X, res_x, sizeof(res_x));
469 memcpy(r->Y, res_y, sizeof(res_y));
470 memcpy(r->Z, res_z, sizeof(res_z));
471 }
472 #endif
473
474 /* r = in^-1 mod p */
475 static void ecp_nistz256_mod_inverse(BN_ULONG r[P256_LIMBS],
476 const BN_ULONG in[P256_LIMBS])
477 {
478 /*
479 * The poly is ffffffff 00000001 00000000 00000000 00000000 ffffffff
480 * ffffffff ffffffff We use FLT and used poly-2 as exponent
481 */
482 BN_ULONG p2[P256_LIMBS];
483 BN_ULONG p4[P256_LIMBS];
484 BN_ULONG p8[P256_LIMBS];
485 BN_ULONG p16[P256_LIMBS];
486 BN_ULONG p32[P256_LIMBS];
487 BN_ULONG res[P256_LIMBS];
488 int i;
489
490 ecp_nistz256_sqr_mont(res, in);
491 ecp_nistz256_mul_mont(p2, res, in); /* 3*p */
492
493 ecp_nistz256_sqr_mont(res, p2);
494 ecp_nistz256_sqr_mont(res, res);
495 ecp_nistz256_mul_mont(p4, res, p2); /* f*p */
496
497 ecp_nistz256_sqr_mont(res, p4);
498 ecp_nistz256_sqr_mont(res, res);
499 ecp_nistz256_sqr_mont(res, res);
500 ecp_nistz256_sqr_mont(res, res);
501 ecp_nistz256_mul_mont(p8, res, p4); /* ff*p */
502
503 ecp_nistz256_sqr_mont(res, p8);
504 for (i = 0; i < 7; i++)
505 ecp_nistz256_sqr_mont(res, res);
506 ecp_nistz256_mul_mont(p16, res, p8); /* ffff*p */
507
508 ecp_nistz256_sqr_mont(res, p16);
509 for (i = 0; i < 15; i++)
510 ecp_nistz256_sqr_mont(res, res);
511 ecp_nistz256_mul_mont(p32, res, p16); /* ffffffff*p */
512
513 ecp_nistz256_sqr_mont(res, p32);
514 for (i = 0; i < 31; i++)
515 ecp_nistz256_sqr_mont(res, res);
516 ecp_nistz256_mul_mont(res, res, in);
517
518 for (i = 0; i < 32 * 4; i++)
519 ecp_nistz256_sqr_mont(res, res);
520 ecp_nistz256_mul_mont(res, res, p32);
521
522 for (i = 0; i < 32; i++)
523 ecp_nistz256_sqr_mont(res, res);
524 ecp_nistz256_mul_mont(res, res, p32);
525
526 for (i = 0; i < 16; i++)
527 ecp_nistz256_sqr_mont(res, res);
528 ecp_nistz256_mul_mont(res, res, p16);
529
530 for (i = 0; i < 8; i++)
531 ecp_nistz256_sqr_mont(res, res);
532 ecp_nistz256_mul_mont(res, res, p8);
533
534 ecp_nistz256_sqr_mont(res, res);
535 ecp_nistz256_sqr_mont(res, res);
536 ecp_nistz256_sqr_mont(res, res);
537 ecp_nistz256_sqr_mont(res, res);
538 ecp_nistz256_mul_mont(res, res, p4);
539
540 ecp_nistz256_sqr_mont(res, res);
541 ecp_nistz256_sqr_mont(res, res);
542 ecp_nistz256_mul_mont(res, res, p2);
543
544 ecp_nistz256_sqr_mont(res, res);
545 ecp_nistz256_sqr_mont(res, res);
546 ecp_nistz256_mul_mont(res, res, in);
547
548 memcpy(r, res, sizeof(res));
549 }
550
551 /*
552 * ecp_nistz256_bignum_to_field_elem copies the contents of |in| to |out| and
553 * returns one if it fits. Otherwise it returns zero.
554 */
555 __owur static int ecp_nistz256_bignum_to_field_elem(BN_ULONG out[P256_LIMBS],
556 const BIGNUM *in)
557 {
558 return bn_copy_words(out, in, P256_LIMBS);
559 }
560
561 /* r = sum(scalar[i]*point[i]) */
562 __owur static int ecp_nistz256_windowed_mul(const EC_GROUP *group,
563 P256_POINT *r,
564 const BIGNUM **scalar,
565 const EC_POINT **point,
566 size_t num, BN_CTX *ctx)
567 {
568 size_t i;
569 int j, ret = 0;
570 unsigned int idx;
571 unsigned char (*p_str)[33] = NULL;
572 const unsigned int window_size = 5;
573 const unsigned int mask = (1 << (window_size + 1)) - 1;
574 unsigned int wvalue;
575 P256_POINT *temp; /* place for 5 temporary points */
576 const BIGNUM **scalars = NULL;
577 P256_POINT (*table)[16] = NULL;
578 void *table_storage = NULL;
579
580 if ((num * 16 + 6) > OPENSSL_MALLOC_MAX_NELEMS(P256_POINT)
581 || (table_storage =
582 OPENSSL_malloc((num * 16 + 5) * sizeof(P256_POINT) + 64)) == NULL
583 || (p_str =
584 OPENSSL_malloc(num * 33 * sizeof(unsigned char))) == NULL
585 || (scalars = OPENSSL_malloc(num * sizeof(BIGNUM *))) == NULL) {
586 ECerr(EC_F_ECP_NISTZ256_WINDOWED_MUL, ERR_R_MALLOC_FAILURE);
587 goto err;
588 }
589
590 table = (void *)ALIGNPTR(table_storage, 64);
591 temp = (P256_POINT *)(table + num);
592
593 for (i = 0; i < num; i++) {
594 P256_POINT *row = table[i];
595
596 /* This is an unusual input, we don't guarantee constant-timeness. */
597 if ((BN_num_bits(scalar[i]) > 256) || BN_is_negative(scalar[i])) {
598 BIGNUM *mod;
599
600 if ((mod = BN_CTX_get(ctx)) == NULL)
601 goto err;
602 if (!BN_nnmod(mod, scalar[i], group->order, ctx)) {
603 ECerr(EC_F_ECP_NISTZ256_WINDOWED_MUL, ERR_R_BN_LIB);
604 goto err;
605 }
606 scalars[i] = mod;
607 } else
608 scalars[i] = scalar[i];
609
610 for (j = 0; j < bn_get_top(scalars[i]) * BN_BYTES; j += BN_BYTES) {
611 BN_ULONG d = bn_get_words(scalars[i])[j / BN_BYTES];
612
613 p_str[i][j + 0] = (unsigned char)d;
614 p_str[i][j + 1] = (unsigned char)(d >> 8);
615 p_str[i][j + 2] = (unsigned char)(d >> 16);
616 p_str[i][j + 3] = (unsigned char)(d >>= 24);
617 if (BN_BYTES == 8) {
618 d >>= 8;
619 p_str[i][j + 4] = (unsigned char)d;
620 p_str[i][j + 5] = (unsigned char)(d >> 8);
621 p_str[i][j + 6] = (unsigned char)(d >> 16);
622 p_str[i][j + 7] = (unsigned char)(d >> 24);
623 }
624 }
625 for (; j < 33; j++)
626 p_str[i][j] = 0;
627
628 if (!ecp_nistz256_bignum_to_field_elem(temp[0].X, point[i]->X)
629 || !ecp_nistz256_bignum_to_field_elem(temp[0].Y, point[i]->Y)
630 || !ecp_nistz256_bignum_to_field_elem(temp[0].Z, point[i]->Z)) {
631 ECerr(EC_F_ECP_NISTZ256_WINDOWED_MUL,
632 EC_R_COORDINATES_OUT_OF_RANGE);
633 goto err;
634 }
635
636 /*
637 * row[0] is implicitly (0,0,0) (the point at infinity), therefore it
638 * is not stored. All other values are actually stored with an offset
639 * of -1 in table.
640 */
641
642 ecp_nistz256_scatter_w5 (row, &temp[0], 1);
643 ecp_nistz256_point_double(&temp[1], &temp[0]); /*1+1=2 */
644 ecp_nistz256_scatter_w5 (row, &temp[1], 2);
645 ecp_nistz256_point_add (&temp[2], &temp[1], &temp[0]); /*2+1=3 */
646 ecp_nistz256_scatter_w5 (row, &temp[2], 3);
647 ecp_nistz256_point_double(&temp[1], &temp[1]); /*2*2=4 */
648 ecp_nistz256_scatter_w5 (row, &temp[1], 4);
649 ecp_nistz256_point_double(&temp[2], &temp[2]); /*2*3=6 */
650 ecp_nistz256_scatter_w5 (row, &temp[2], 6);
651 ecp_nistz256_point_add (&temp[3], &temp[1], &temp[0]); /*4+1=5 */
652 ecp_nistz256_scatter_w5 (row, &temp[3], 5);
653 ecp_nistz256_point_add (&temp[4], &temp[2], &temp[0]); /*6+1=7 */
654 ecp_nistz256_scatter_w5 (row, &temp[4], 7);
655 ecp_nistz256_point_double(&temp[1], &temp[1]); /*2*4=8 */
656 ecp_nistz256_scatter_w5 (row, &temp[1], 8);
657 ecp_nistz256_point_double(&temp[2], &temp[2]); /*2*6=12 */
658 ecp_nistz256_scatter_w5 (row, &temp[2], 12);
659 ecp_nistz256_point_double(&temp[3], &temp[3]); /*2*5=10 */
660 ecp_nistz256_scatter_w5 (row, &temp[3], 10);
661 ecp_nistz256_point_double(&temp[4], &temp[4]); /*2*7=14 */
662 ecp_nistz256_scatter_w5 (row, &temp[4], 14);
663 ecp_nistz256_point_add (&temp[2], &temp[2], &temp[0]); /*12+1=13*/
664 ecp_nistz256_scatter_w5 (row, &temp[2], 13);
665 ecp_nistz256_point_add (&temp[3], &temp[3], &temp[0]); /*10+1=11*/
666 ecp_nistz256_scatter_w5 (row, &temp[3], 11);
667 ecp_nistz256_point_add (&temp[4], &temp[4], &temp[0]); /*14+1=15*/
668 ecp_nistz256_scatter_w5 (row, &temp[4], 15);
669 ecp_nistz256_point_add (&temp[2], &temp[1], &temp[0]); /*8+1=9 */
670 ecp_nistz256_scatter_w5 (row, &temp[2], 9);
671 ecp_nistz256_point_double(&temp[1], &temp[1]); /*2*8=16 */
672 ecp_nistz256_scatter_w5 (row, &temp[1], 16);
673 }
674
675 idx = 255;
676
677 wvalue = p_str[0][(idx - 1) / 8];
678 wvalue = (wvalue >> ((idx - 1) % 8)) & mask;
679
680 /*
681 * We gather to temp[0], because we know it's position relative
682 * to table
683 */
684 ecp_nistz256_gather_w5(&temp[0], table[0], _booth_recode_w5(wvalue) >> 1);
685 memcpy(r, &temp[0], sizeof(temp[0]));
686
687 while (idx >= 5) {
688 for (i = (idx == 255 ? 1 : 0); i < num; i++) {
689 unsigned int off = (idx - 1) / 8;
690
691 wvalue = p_str[i][off] | p_str[i][off + 1] << 8;
692 wvalue = (wvalue >> ((idx - 1) % 8)) & mask;
693
694 wvalue = _booth_recode_w5(wvalue);
695
696 ecp_nistz256_gather_w5(&temp[0], table[i], wvalue >> 1);
697
698 ecp_nistz256_neg(temp[1].Y, temp[0].Y);
699 copy_conditional(temp[0].Y, temp[1].Y, (wvalue & 1));
700
701 ecp_nistz256_point_add(r, r, &temp[0]);
702 }
703
704 idx -= window_size;
705
706 ecp_nistz256_point_double(r, r);
707 ecp_nistz256_point_double(r, r);
708 ecp_nistz256_point_double(r, r);
709 ecp_nistz256_point_double(r, r);
710 ecp_nistz256_point_double(r, r);
711 }
712
713 /* Final window */
714 for (i = 0; i < num; i++) {
715 wvalue = p_str[i][0];
716 wvalue = (wvalue << 1) & mask;
717
718 wvalue = _booth_recode_w5(wvalue);
719
720 ecp_nistz256_gather_w5(&temp[0], table[i], wvalue >> 1);
721
722 ecp_nistz256_neg(temp[1].Y, temp[0].Y);
723 copy_conditional(temp[0].Y, temp[1].Y, wvalue & 1);
724
725 ecp_nistz256_point_add(r, r, &temp[0]);
726 }
727
728 ret = 1;
729 err:
730 OPENSSL_free(table_storage);
731 OPENSSL_free(p_str);
732 OPENSSL_free(scalars);
733 return ret;
734 }
735
736 /* Coordinates of G, for which we have precomputed tables */
737 const static BN_ULONG def_xG[P256_LIMBS] = {
738 TOBN(0x79e730d4, 0x18a9143c), TOBN(0x75ba95fc, 0x5fedb601),
739 TOBN(0x79fb732b, 0x77622510), TOBN(0x18905f76, 0xa53755c6)
740 };
741
742 const static BN_ULONG def_yG[P256_LIMBS] = {
743 TOBN(0xddf25357, 0xce95560a), TOBN(0x8b4ab8e4, 0xba19e45c),
744 TOBN(0xd2e88688, 0xdd21f325), TOBN(0x8571ff18, 0x25885d85)
745 };
746
747 /*
748 * ecp_nistz256_is_affine_G returns one if |generator| is the standard, P-256
749 * generator.
750 */
751 static int ecp_nistz256_is_affine_G(const EC_POINT *generator)
752 {
753 return (bn_get_top(generator->X) == P256_LIMBS) &&
754 (bn_get_top(generator->Y) == P256_LIMBS) &&
755 (bn_get_top(generator->Z) == (P256_LIMBS - P256_LIMBS / 8)) &&
756 is_equal(bn_get_words(generator->X), def_xG) &&
757 is_equal(bn_get_words(generator->Y), def_yG) &&
758 is_one(bn_get_words(generator->Z));
759 }
760
761 __owur static int ecp_nistz256_mult_precompute(EC_GROUP *group, BN_CTX *ctx)
762 {
763 /*
764 * We precompute a table for a Booth encoded exponent (wNAF) based
765 * computation. Each table holds 64 values for safe access, with an
766 * implicit value of infinity at index zero. We use window of size 7, and
767 * therefore require ceil(256/7) = 37 tables.
768 */
769 const BIGNUM *order;
770 EC_POINT *P = NULL, *T = NULL;
771 const EC_POINT *generator;
772 NISTZ256_PRE_COMP *pre_comp;
773 BN_CTX *new_ctx = NULL;
774 int i, j, k, ret = 0;
775 size_t w;
776
777 PRECOMP256_ROW *preComputedTable = NULL;
778 unsigned char *precomp_storage = NULL;
779
780 /* if there is an old NISTZ256_PRE_COMP object, throw it away */
781 EC_pre_comp_free(group);
782 generator = EC_GROUP_get0_generator(group);
783 if (generator == NULL) {
784 ECerr(EC_F_ECP_NISTZ256_MULT_PRECOMPUTE, EC_R_UNDEFINED_GENERATOR);
785 return 0;
786 }
787
788 if (ecp_nistz256_is_affine_G(generator)) {
789 /*
790 * No need to calculate tables for the standard generator because we
791 * have them statically.
792 */
793 return 1;
794 }
795
796 if ((pre_comp = ecp_nistz256_pre_comp_new(group)) == NULL)
797 return 0;
798
799 if (ctx == NULL) {
800 ctx = new_ctx = BN_CTX_new();
801 if (ctx == NULL)
802 goto err;
803 }
804
805 BN_CTX_start(ctx);
806
807 order = EC_GROUP_get0_order(group);
808 if (order == NULL)
809 goto err;
810
811 if (BN_is_zero(order)) {
812 ECerr(EC_F_ECP_NISTZ256_MULT_PRECOMPUTE, EC_R_UNKNOWN_ORDER);
813 goto err;
814 }
815
816 w = 7;
817
818 if ((precomp_storage =
819 OPENSSL_malloc(37 * 64 * sizeof(P256_POINT_AFFINE) + 64)) == NULL) {
820 ECerr(EC_F_ECP_NISTZ256_MULT_PRECOMPUTE, ERR_R_MALLOC_FAILURE);
821 goto err;
822 }
823
824 preComputedTable = (void *)ALIGNPTR(precomp_storage, 64);
825
826 P = EC_POINT_new(group);
827 T = EC_POINT_new(group);
828 if (P == NULL || T == NULL)
829 goto err;
830
831 /*
832 * The zero entry is implicitly infinity, and we skip it, storing other
833 * values with -1 offset.
834 */
835 if (!EC_POINT_copy(T, generator))
836 goto err;
837
838 for (k = 0; k < 64; k++) {
839 if (!EC_POINT_copy(P, T))
840 goto err;
841 for (j = 0; j < 37; j++) {
842 P256_POINT_AFFINE temp;
843 /*
844 * It would be faster to use EC_POINTs_make_affine and
845 * make multiple points affine at the same time.
846 */
847 if (!EC_POINT_make_affine(group, P, ctx))
848 goto err;
849 if (!ecp_nistz256_bignum_to_field_elem(temp.X, P->X) ||
850 !ecp_nistz256_bignum_to_field_elem(temp.Y, P->Y)) {
851 ECerr(EC_F_ECP_NISTZ256_MULT_PRECOMPUTE,
852 EC_R_COORDINATES_OUT_OF_RANGE);
853 goto err;
854 }
855 ecp_nistz256_scatter_w7(preComputedTable[j], &temp, k);
856 for (i = 0; i < 7; i++) {
857 if (!EC_POINT_dbl(group, P, P, ctx))
858 goto err;
859 }
860 }
861 if (!EC_POINT_add(group, T, T, generator, ctx))
862 goto err;
863 }
864
865 pre_comp->group = group;
866 pre_comp->w = w;
867 pre_comp->precomp = preComputedTable;
868 pre_comp->precomp_storage = precomp_storage;
869 precomp_storage = NULL;
870 SETPRECOMP(group, nistz256, pre_comp);
871 pre_comp = NULL;
872 ret = 1;
873
874 err:
875 if (ctx != NULL)
876 BN_CTX_end(ctx);
877 BN_CTX_free(new_ctx);
878
879 EC_nistz256_pre_comp_free(pre_comp);
880 OPENSSL_free(precomp_storage);
881 EC_POINT_free(P);
882 EC_POINT_free(T);
883 return ret;
884 }
885
886 /*
887 * Note that by default ECP_NISTZ256_AVX2 is undefined. While it's great
888 * code processing 4 points in parallel, corresponding serial operation
889 * is several times slower, because it uses 29x29=58-bit multiplication
890 * as opposite to 64x64=128-bit in integer-only scalar case. As result
891 * it doesn't provide *significant* performance improvement. Note that
892 * just defining ECP_NISTZ256_AVX2 is not sufficient to make it work,
893 * you'd need to compile even asm/ecp_nistz256-avx.pl module.
894 */
895 #if defined(ECP_NISTZ256_AVX2)
896 # if !(defined(__x86_64) || defined(__x86_64__) || \
897 defined(_M_AMD64) || defined(_MX64)) || \
898 !(defined(__GNUC__) || defined(_MSC_VER)) /* this is for ALIGN32 */
899 # undef ECP_NISTZ256_AVX2
900 # else
901 /* Constant time access, loading four values, from four consecutive tables */
902 void ecp_nistz256_avx2_multi_gather_w7(void *result, const void *in,
903 int index0, int index1, int index2,
904 int index3);
905 void ecp_nistz256_avx2_transpose_convert(void *RESULTx4, const void *in);
906 void ecp_nistz256_avx2_convert_transpose_back(void *result, const void *Ax4);
907 void ecp_nistz256_avx2_point_add_affine_x4(void *RESULTx4, const void *Ax4,
908 const void *Bx4);
909 void ecp_nistz256_avx2_point_add_affines_x4(void *RESULTx4, const void *Ax4,
910 const void *Bx4);
911 void ecp_nistz256_avx2_to_mont(void *RESULTx4, const void *Ax4);
912 void ecp_nistz256_avx2_from_mont(void *RESULTx4, const void *Ax4);
913 void ecp_nistz256_avx2_set1(void *RESULTx4);
914 int ecp_nistz_avx2_eligible(void);
915
916 static void booth_recode_w7(unsigned char *sign,
917 unsigned char *digit, unsigned char in)
918 {
919 unsigned char s, d;
920
921 s = ~((in >> 7) - 1);
922 d = (1 << 8) - in - 1;
923 d = (d & s) | (in & ~s);
924 d = (d >> 1) + (d & 1);
925
926 *sign = s & 1;
927 *digit = d;
928 }
929
930 /*
931 * ecp_nistz256_avx2_mul_g performs multiplication by G, using only the
932 * precomputed table. It does 4 affine point additions in parallel,
933 * significantly speeding up point multiplication for a fixed value.
934 */
935 static void ecp_nistz256_avx2_mul_g(P256_POINT *r,
936 unsigned char p_str[33],
937 const P256_POINT_AFFINE(*preComputedTable)[64])
938 {
939 const unsigned int window_size = 7;
940 const unsigned int mask = (1 << (window_size + 1)) - 1;
941 unsigned int wvalue;
942 /* Using 4 windows at a time */
943 unsigned char sign0, digit0;
944 unsigned char sign1, digit1;
945 unsigned char sign2, digit2;
946 unsigned char sign3, digit3;
947 unsigned int idx = 0;
948 BN_ULONG tmp[P256_LIMBS];
949 int i;
950
951 ALIGN32 BN_ULONG aX4[4 * 9 * 3] = { 0 };
952 ALIGN32 BN_ULONG bX4[4 * 9 * 2] = { 0 };
953 ALIGN32 P256_POINT_AFFINE point_arr[4];
954 ALIGN32 P256_POINT res_point_arr[4];
955
956 /* Initial four windows */
957 wvalue = *((u16 *) & p_str[0]);
958 wvalue = (wvalue << 1) & mask;
959 idx += window_size;
960 booth_recode_w7(&sign0, &digit0, wvalue);
961 wvalue = *((u16 *) & p_str[(idx - 1) / 8]);
962 wvalue = (wvalue >> ((idx - 1) % 8)) & mask;
963 idx += window_size;
964 booth_recode_w7(&sign1, &digit1, wvalue);
965 wvalue = *((u16 *) & p_str[(idx - 1) / 8]);
966 wvalue = (wvalue >> ((idx - 1) % 8)) & mask;
967 idx += window_size;
968 booth_recode_w7(&sign2, &digit2, wvalue);
969 wvalue = *((u16 *) & p_str[(idx - 1) / 8]);
970 wvalue = (wvalue >> ((idx - 1) % 8)) & mask;
971 idx += window_size;
972 booth_recode_w7(&sign3, &digit3, wvalue);
973
974 ecp_nistz256_avx2_multi_gather_w7(point_arr, preComputedTable[0],
975 digit0, digit1, digit2, digit3);
976
977 ecp_nistz256_neg(tmp, point_arr[0].Y);
978 copy_conditional(point_arr[0].Y, tmp, sign0);
979 ecp_nistz256_neg(tmp, point_arr[1].Y);
980 copy_conditional(point_arr[1].Y, tmp, sign1);
981 ecp_nistz256_neg(tmp, point_arr[2].Y);
982 copy_conditional(point_arr[2].Y, tmp, sign2);
983 ecp_nistz256_neg(tmp, point_arr[3].Y);
984 copy_conditional(point_arr[3].Y, tmp, sign3);
985
986 ecp_nistz256_avx2_transpose_convert(aX4, point_arr);
987 ecp_nistz256_avx2_to_mont(aX4, aX4);
988 ecp_nistz256_avx2_to_mont(&aX4[4 * 9], &aX4[4 * 9]);
989 ecp_nistz256_avx2_set1(&aX4[4 * 9 * 2]);
990
991 wvalue = *((u16 *) & p_str[(idx - 1) / 8]);
992 wvalue = (wvalue >> ((idx - 1) % 8)) & mask;
993 idx += window_size;
994 booth_recode_w7(&sign0, &digit0, wvalue);
995 wvalue = *((u16 *) & p_str[(idx - 1) / 8]);
996 wvalue = (wvalue >> ((idx - 1) % 8)) & mask;
997 idx += window_size;
998 booth_recode_w7(&sign1, &digit1, wvalue);
999 wvalue = *((u16 *) & p_str[(idx - 1) / 8]);
1000 wvalue = (wvalue >> ((idx - 1) % 8)) & mask;
1001 idx += window_size;
1002 booth_recode_w7(&sign2, &digit2, wvalue);
1003 wvalue = *((u16 *) & p_str[(idx - 1) / 8]);
1004 wvalue = (wvalue >> ((idx - 1) % 8)) & mask;
1005 idx += window_size;
1006 booth_recode_w7(&sign3, &digit3, wvalue);
1007
1008 ecp_nistz256_avx2_multi_gather_w7(point_arr, preComputedTable[4 * 1],
1009 digit0, digit1, digit2, digit3);
1010
1011 ecp_nistz256_neg(tmp, point_arr[0].Y);
1012 copy_conditional(point_arr[0].Y, tmp, sign0);
1013 ecp_nistz256_neg(tmp, point_arr[1].Y);
1014 copy_conditional(point_arr[1].Y, tmp, sign1);
1015 ecp_nistz256_neg(tmp, point_arr[2].Y);
1016 copy_conditional(point_arr[2].Y, tmp, sign2);
1017 ecp_nistz256_neg(tmp, point_arr[3].Y);
1018 copy_conditional(point_arr[3].Y, tmp, sign3);
1019
1020 ecp_nistz256_avx2_transpose_convert(bX4, point_arr);
1021 ecp_nistz256_avx2_to_mont(bX4, bX4);
1022 ecp_nistz256_avx2_to_mont(&bX4[4 * 9], &bX4[4 * 9]);
1023 /* Optimized when both inputs are affine */
1024 ecp_nistz256_avx2_point_add_affines_x4(aX4, aX4, bX4);
1025
1026 for (i = 2; i < 9; i++) {
1027 wvalue = *((u16 *) & p_str[(idx - 1) / 8]);
1028 wvalue = (wvalue >> ((idx - 1) % 8)) & mask;
1029 idx += window_size;
1030 booth_recode_w7(&sign0, &digit0, wvalue);
1031 wvalue = *((u16 *) & p_str[(idx - 1) / 8]);
1032 wvalue = (wvalue >> ((idx - 1) % 8)) & mask;
1033 idx += window_size;
1034 booth_recode_w7(&sign1, &digit1, wvalue);
1035 wvalue = *((u16 *) & p_str[(idx - 1) / 8]);
1036 wvalue = (wvalue >> ((idx - 1) % 8)) & mask;
1037 idx += window_size;
1038 booth_recode_w7(&sign2, &digit2, wvalue);
1039 wvalue = *((u16 *) & p_str[(idx - 1) / 8]);
1040 wvalue = (wvalue >> ((idx - 1) % 8)) & mask;
1041 idx += window_size;
1042 booth_recode_w7(&sign3, &digit3, wvalue);
1043
1044 ecp_nistz256_avx2_multi_gather_w7(point_arr,
1045 preComputedTable[4 * i],
1046 digit0, digit1, digit2, digit3);
1047
1048 ecp_nistz256_neg(tmp, point_arr[0].Y);
1049 copy_conditional(point_arr[0].Y, tmp, sign0);
1050 ecp_nistz256_neg(tmp, point_arr[1].Y);
1051 copy_conditional(point_arr[1].Y, tmp, sign1);
1052 ecp_nistz256_neg(tmp, point_arr[2].Y);
1053 copy_conditional(point_arr[2].Y, tmp, sign2);
1054 ecp_nistz256_neg(tmp, point_arr[3].Y);
1055 copy_conditional(point_arr[3].Y, tmp, sign3);
1056
1057 ecp_nistz256_avx2_transpose_convert(bX4, point_arr);
1058 ecp_nistz256_avx2_to_mont(bX4, bX4);
1059 ecp_nistz256_avx2_to_mont(&bX4[4 * 9], &bX4[4 * 9]);
1060
1061 ecp_nistz256_avx2_point_add_affine_x4(aX4, aX4, bX4);
1062 }
1063
1064 ecp_nistz256_avx2_from_mont(&aX4[4 * 9 * 0], &aX4[4 * 9 * 0]);
1065 ecp_nistz256_avx2_from_mont(&aX4[4 * 9 * 1], &aX4[4 * 9 * 1]);
1066 ecp_nistz256_avx2_from_mont(&aX4[4 * 9 * 2], &aX4[4 * 9 * 2]);
1067
1068 ecp_nistz256_avx2_convert_transpose_back(res_point_arr, aX4);
1069 /* Last window is performed serially */
1070 wvalue = *((u16 *) & p_str[(idx - 1) / 8]);
1071 wvalue = (wvalue >> ((idx - 1) % 8)) & mask;
1072 booth_recode_w7(&sign0, &digit0, wvalue);
1073 ecp_nistz256_gather_w7((P256_POINT_AFFINE *)r,
1074 preComputedTable[36], digit0);
1075 ecp_nistz256_neg(tmp, r->Y);
1076 copy_conditional(r->Y, tmp, sign0);
1077 memcpy(r->Z, ONE, sizeof(ONE));
1078 /* Sum the four windows */
1079 ecp_nistz256_point_add(r, r, &res_point_arr[0]);
1080 ecp_nistz256_point_add(r, r, &res_point_arr[1]);
1081 ecp_nistz256_point_add(r, r, &res_point_arr[2]);
1082 ecp_nistz256_point_add(r, r, &res_point_arr[3]);
1083 }
1084 # endif
1085 #endif
1086
1087 __owur static int ecp_nistz256_set_from_affine(EC_POINT *out, const EC_GROUP *group,
1088 const P256_POINT_AFFINE *in,
1089 BN_CTX *ctx)
1090 {
1091 BIGNUM *x, *y;
1092 BN_ULONG d_x[P256_LIMBS], d_y[P256_LIMBS];
1093 int ret = 0;
1094
1095 x = BN_new();
1096 if (x == NULL)
1097 return 0;
1098 y = BN_new();
1099 if (y == NULL) {
1100 BN_free(x);
1101 return 0;
1102 }
1103 memcpy(d_x, in->X, sizeof(d_x));
1104 bn_set_static_words(x, d_x, P256_LIMBS);
1105
1106 memcpy(d_y, in->Y, sizeof(d_y));
1107 bn_set_static_words(y, d_y, P256_LIMBS);
1108
1109 ret = EC_POINT_set_affine_coordinates_GFp(group, out, x, y, ctx);
1110
1111 BN_free(x);
1112 BN_free(y);
1113
1114 return ret;
1115 }
1116
1117 /* r = scalar*G + sum(scalars[i]*points[i]) */
1118 __owur static int ecp_nistz256_points_mul(const EC_GROUP *group,
1119 EC_POINT *r,
1120 const BIGNUM *scalar,
1121 size_t num,
1122 const EC_POINT *points[],
1123 const BIGNUM *scalars[], BN_CTX *ctx)
1124 {
1125 int i = 0, ret = 0, no_precomp_for_generator = 0, p_is_infinity = 0;
1126 size_t j;
1127 unsigned char p_str[33] = { 0 };
1128 const PRECOMP256_ROW *preComputedTable = NULL;
1129 const NISTZ256_PRE_COMP *pre_comp = NULL;
1130 const EC_POINT *generator = NULL;
1131 BN_CTX *new_ctx = NULL;
1132 const BIGNUM **new_scalars = NULL;
1133 const EC_POINT **new_points = NULL;
1134 unsigned int idx = 0;
1135 const unsigned int window_size = 7;
1136 const unsigned int mask = (1 << (window_size + 1)) - 1;
1137 unsigned int wvalue;
1138 ALIGN32 union {
1139 P256_POINT p;
1140 P256_POINT_AFFINE a;
1141 } t, p;
1142 BIGNUM *tmp_scalar;
1143
1144 if ((num + 1) == 0 || (num + 1) > OPENSSL_MALLOC_MAX_NELEMS(void *)) {
1145 ECerr(EC_F_ECP_NISTZ256_POINTS_MUL, ERR_R_MALLOC_FAILURE);
1146 return 0;
1147 }
1148
1149 if (group->meth != r->meth) {
1150 ECerr(EC_F_ECP_NISTZ256_POINTS_MUL, EC_R_INCOMPATIBLE_OBJECTS);
1151 return 0;
1152 }
1153
1154 if ((scalar == NULL) && (num == 0))
1155 return EC_POINT_set_to_infinity(group, r);
1156
1157 for (j = 0; j < num; j++) {
1158 if (group->meth != points[j]->meth) {
1159 ECerr(EC_F_ECP_NISTZ256_POINTS_MUL, EC_R_INCOMPATIBLE_OBJECTS);
1160 return 0;
1161 }
1162 }
1163
1164 if (ctx == NULL) {
1165 ctx = new_ctx = BN_CTX_new();
1166 if (ctx == NULL)
1167 goto err;
1168 }
1169
1170 BN_CTX_start(ctx);
1171
1172 if (scalar) {
1173 generator = EC_GROUP_get0_generator(group);
1174 if (generator == NULL) {
1175 ECerr(EC_F_ECP_NISTZ256_POINTS_MUL, EC_R_UNDEFINED_GENERATOR);
1176 goto err;
1177 }
1178
1179 /* look if we can use precomputed multiples of generator */
1180 pre_comp = group->pre_comp.nistz256;
1181
1182 if (pre_comp) {
1183 /*
1184 * If there is a precomputed table for the generator, check that
1185 * it was generated with the same generator.
1186 */
1187 EC_POINT *pre_comp_generator = EC_POINT_new(group);
1188 if (pre_comp_generator == NULL)
1189 goto err;
1190
1191 if (!ecp_nistz256_set_from_affine(pre_comp_generator,
1192 group, pre_comp->precomp[0],
1193 ctx)) {
1194 EC_POINT_free(pre_comp_generator);
1195 goto err;
1196 }
1197
1198 if (0 == EC_POINT_cmp(group, generator, pre_comp_generator, ctx))
1199 preComputedTable = (const PRECOMP256_ROW *)pre_comp->precomp;
1200
1201 EC_POINT_free(pre_comp_generator);
1202 }
1203
1204 if (preComputedTable == NULL && ecp_nistz256_is_affine_G(generator)) {
1205 /*
1206 * If there is no precomputed data, but the generator is the
1207 * default, a hardcoded table of precomputed data is used. This
1208 * is because applications, such as Apache, do not use
1209 * EC_KEY_precompute_mult.
1210 */
1211 preComputedTable = ecp_nistz256_precomputed;
1212 }
1213
1214 if (preComputedTable) {
1215 if ((BN_num_bits(scalar) > 256)
1216 || BN_is_negative(scalar)) {
1217 if ((tmp_scalar = BN_CTX_get(ctx)) == NULL)
1218 goto err;
1219
1220 if (!BN_nnmod(tmp_scalar, scalar, group->order, ctx)) {
1221 ECerr(EC_F_ECP_NISTZ256_POINTS_MUL, ERR_R_BN_LIB);
1222 goto err;
1223 }
1224 scalar = tmp_scalar;
1225 }
1226
1227 for (i = 0; i < bn_get_top(scalar) * BN_BYTES; i += BN_BYTES) {
1228 BN_ULONG d = bn_get_words(scalar)[i / BN_BYTES];
1229
1230 p_str[i + 0] = (unsigned char)d;
1231 p_str[i + 1] = (unsigned char)(d >> 8);
1232 p_str[i + 2] = (unsigned char)(d >> 16);
1233 p_str[i + 3] = (unsigned char)(d >>= 24);
1234 if (BN_BYTES == 8) {
1235 d >>= 8;
1236 p_str[i + 4] = (unsigned char)d;
1237 p_str[i + 5] = (unsigned char)(d >> 8);
1238 p_str[i + 6] = (unsigned char)(d >> 16);
1239 p_str[i + 7] = (unsigned char)(d >> 24);
1240 }
1241 }
1242
1243 for (; i < 33; i++)
1244 p_str[i] = 0;
1245
1246 #if defined(ECP_NISTZ256_AVX2)
1247 if (ecp_nistz_avx2_eligible()) {
1248 ecp_nistz256_avx2_mul_g(&p.p, p_str, preComputedTable);
1249 } else
1250 #endif
1251 {
1252 /* First window */
1253 wvalue = (p_str[0] << 1) & mask;
1254 idx += window_size;
1255
1256 wvalue = _booth_recode_w7(wvalue);
1257
1258 ecp_nistz256_gather_w7(&p.a, preComputedTable[0],
1259 wvalue >> 1);
1260
1261 ecp_nistz256_neg(p.p.Z, p.p.Y);
1262 copy_conditional(p.p.Y, p.p.Z, wvalue & 1);
1263
1264 memcpy(p.p.Z, ONE, sizeof(ONE));
1265
1266 for (i = 1; i < 37; i++) {
1267 unsigned int off = (idx - 1) / 8;
1268 wvalue = p_str[off] | p_str[off + 1] << 8;
1269 wvalue = (wvalue >> ((idx - 1) % 8)) & mask;
1270 idx += window_size;
1271
1272 wvalue = _booth_recode_w7(wvalue);
1273
1274 ecp_nistz256_gather_w7(&t.a,
1275 preComputedTable[i], wvalue >> 1);
1276
1277 ecp_nistz256_neg(t.p.Z, t.a.Y);
1278 copy_conditional(t.a.Y, t.p.Z, wvalue & 1);
1279
1280 ecp_nistz256_point_add_affine(&p.p, &p.p, &t.a);
1281 }
1282 }
1283 } else {
1284 p_is_infinity = 1;
1285 no_precomp_for_generator = 1;
1286 }
1287 } else
1288 p_is_infinity = 1;
1289
1290 if (no_precomp_for_generator) {
1291 /*
1292 * Without a precomputed table for the generator, it has to be
1293 * handled like a normal point.
1294 */
1295 new_scalars = OPENSSL_malloc((num + 1) * sizeof(BIGNUM *));
1296 if (new_scalars == NULL) {
1297 ECerr(EC_F_ECP_NISTZ256_POINTS_MUL, ERR_R_MALLOC_FAILURE);
1298 goto err;
1299 }
1300
1301 new_points = OPENSSL_malloc((num + 1) * sizeof(EC_POINT *));
1302 if (new_points == NULL) {
1303 ECerr(EC_F_ECP_NISTZ256_POINTS_MUL, ERR_R_MALLOC_FAILURE);
1304 goto err;
1305 }
1306
1307 memcpy(new_scalars, scalars, num * sizeof(BIGNUM *));
1308 new_scalars[num] = scalar;
1309 memcpy(new_points, points, num * sizeof(EC_POINT *));
1310 new_points[num] = generator;
1311
1312 scalars = new_scalars;
1313 points = new_points;
1314 num++;
1315 }
1316
1317 if (num) {
1318 P256_POINT *out = &t.p;
1319 if (p_is_infinity)
1320 out = &p.p;
1321
1322 if (!ecp_nistz256_windowed_mul(group, out, scalars, points, num, ctx))
1323 goto err;
1324
1325 if (!p_is_infinity)
1326 ecp_nistz256_point_add(&p.p, &p.p, out);
1327 }
1328
1329 /* Not constant-time, but we're only operating on the public output. */
1330 if (!bn_set_words(r->X, p.p.X, P256_LIMBS) ||
1331 !bn_set_words(r->Y, p.p.Y, P256_LIMBS) ||
1332 !bn_set_words(r->Z, p.p.Z, P256_LIMBS)) {
1333 goto err;
1334 }
1335 r->Z_is_one = is_one(p.p.Z) & 1;
1336
1337 ret = 1;
1338
1339 err:
1340 if (ctx)
1341 BN_CTX_end(ctx);
1342 BN_CTX_free(new_ctx);
1343 OPENSSL_free(new_points);
1344 OPENSSL_free(new_scalars);
1345 return ret;
1346 }
1347
1348 __owur static int ecp_nistz256_get_affine(const EC_GROUP *group,
1349 const EC_POINT *point,
1350 BIGNUM *x, BIGNUM *y, BN_CTX *ctx)
1351 {
1352 BN_ULONG z_inv2[P256_LIMBS];
1353 BN_ULONG z_inv3[P256_LIMBS];
1354 BN_ULONG x_aff[P256_LIMBS];
1355 BN_ULONG y_aff[P256_LIMBS];
1356 BN_ULONG point_x[P256_LIMBS], point_y[P256_LIMBS], point_z[P256_LIMBS];
1357 BN_ULONG x_ret[P256_LIMBS], y_ret[P256_LIMBS];
1358
1359 if (EC_POINT_is_at_infinity(group, point)) {
1360 ECerr(EC_F_ECP_NISTZ256_GET_AFFINE, EC_R_POINT_AT_INFINITY);
1361 return 0;
1362 }
1363
1364 if (!ecp_nistz256_bignum_to_field_elem(point_x, point->X) ||
1365 !ecp_nistz256_bignum_to_field_elem(point_y, point->Y) ||
1366 !ecp_nistz256_bignum_to_field_elem(point_z, point->Z)) {
1367 ECerr(EC_F_ECP_NISTZ256_GET_AFFINE, EC_R_COORDINATES_OUT_OF_RANGE);
1368 return 0;
1369 }
1370
1371 ecp_nistz256_mod_inverse(z_inv3, point_z);
1372 ecp_nistz256_sqr_mont(z_inv2, z_inv3);
1373 ecp_nistz256_mul_mont(x_aff, z_inv2, point_x);
1374
1375 if (x != NULL) {
1376 ecp_nistz256_from_mont(x_ret, x_aff);
1377 if (!bn_set_words(x, x_ret, P256_LIMBS))
1378 return 0;
1379 }
1380
1381 if (y != NULL) {
1382 ecp_nistz256_mul_mont(z_inv3, z_inv3, z_inv2);
1383 ecp_nistz256_mul_mont(y_aff, z_inv3, point_y);
1384 ecp_nistz256_from_mont(y_ret, y_aff);
1385 if (!bn_set_words(y, y_ret, P256_LIMBS))
1386 return 0;
1387 }
1388
1389 return 1;
1390 }
1391
1392 static NISTZ256_PRE_COMP *ecp_nistz256_pre_comp_new(const EC_GROUP *group)
1393 {
1394 NISTZ256_PRE_COMP *ret = NULL;
1395
1396 if (!group)
1397 return NULL;
1398
1399 ret = OPENSSL_zalloc(sizeof(*ret));
1400
1401 if (ret == NULL) {
1402 ECerr(EC_F_ECP_NISTZ256_PRE_COMP_NEW, ERR_R_MALLOC_FAILURE);
1403 return ret;
1404 }
1405
1406 ret->group = group;
1407 ret->w = 6; /* default */
1408 ret->references = 1;
1409
1410 ret->lock = CRYPTO_THREAD_lock_new();
1411 if (ret->lock == NULL) {
1412 ECerr(EC_F_ECP_NISTZ256_PRE_COMP_NEW, ERR_R_MALLOC_FAILURE);
1413 OPENSSL_free(ret);
1414 return NULL;
1415 }
1416 return ret;
1417 }
1418
1419 NISTZ256_PRE_COMP *EC_nistz256_pre_comp_dup(NISTZ256_PRE_COMP *p)
1420 {
1421 int i;
1422 if (p != NULL)
1423 CRYPTO_atomic_add(&p->references, 1, &i, p->lock);
1424 return p;
1425 }
1426
1427 void EC_nistz256_pre_comp_free(NISTZ256_PRE_COMP *pre)
1428 {
1429 int i;
1430
1431 if (pre == NULL)
1432 return;
1433
1434 CRYPTO_atomic_add(&pre->references, -1, &i, pre->lock);
1435 REF_PRINT_COUNT("EC_nistz256", x);
1436 if (i > 0)
1437 return;
1438 REF_ASSERT_ISNT(i < 0);
1439
1440 OPENSSL_free(pre->precomp_storage);
1441 CRYPTO_THREAD_lock_free(pre->lock);
1442 OPENSSL_free(pre);
1443 }
1444
1445
1446 static int ecp_nistz256_window_have_precompute_mult(const EC_GROUP *group)
1447 {
1448 /* There is a hard-coded table for the default generator. */
1449 const EC_POINT *generator = EC_GROUP_get0_generator(group);
1450
1451 if (generator != NULL && ecp_nistz256_is_affine_G(generator)) {
1452 /* There is a hard-coded table for the default generator. */
1453 return 1;
1454 }
1455
1456 return HAVEPRECOMP(group, nistz256);
1457 }
1458
1459 const EC_METHOD *EC_GFp_nistz256_method(void)
1460 {
1461 static const EC_METHOD ret = {
1462 EC_FLAGS_DEFAULT_OCT,
1463 NID_X9_62_prime_field,
1464 ec_GFp_mont_group_init,
1465 ec_GFp_mont_group_finish,
1466 ec_GFp_mont_group_clear_finish,
1467 ec_GFp_mont_group_copy,
1468 ec_GFp_mont_group_set_curve,
1469 ec_GFp_simple_group_get_curve,
1470 ec_GFp_simple_group_get_degree,
1471 ec_group_simple_order_bits,
1472 ec_GFp_simple_group_check_discriminant,
1473 ec_GFp_simple_point_init,
1474 ec_GFp_simple_point_finish,
1475 ec_GFp_simple_point_clear_finish,
1476 ec_GFp_simple_point_copy,
1477 ec_GFp_simple_point_set_to_infinity,
1478 ec_GFp_simple_set_Jprojective_coordinates_GFp,
1479 ec_GFp_simple_get_Jprojective_coordinates_GFp,
1480 ec_GFp_simple_point_set_affine_coordinates,
1481 ecp_nistz256_get_affine,
1482 0, 0, 0,
1483 ec_GFp_simple_add,
1484 ec_GFp_simple_dbl,
1485 ec_GFp_simple_invert,
1486 ec_GFp_simple_is_at_infinity,
1487 ec_GFp_simple_is_on_curve,
1488 ec_GFp_simple_cmp,
1489 ec_GFp_simple_make_affine,
1490 ec_GFp_simple_points_make_affine,
1491 ecp_nistz256_points_mul, /* mul */
1492 ecp_nistz256_mult_precompute, /* precompute_mult */
1493 ecp_nistz256_window_have_precompute_mult, /* have_precompute_mult */
1494 ec_GFp_mont_field_mul,
1495 ec_GFp_mont_field_sqr,
1496 0, /* field_div */
1497 ec_GFp_mont_field_encode,
1498 ec_GFp_mont_field_decode,
1499 ec_GFp_mont_field_set_to_one,
1500 ec_key_simple_priv2oct,
1501 ec_key_simple_oct2priv,
1502 0, /* set private */
1503 ec_key_simple_generate_key,
1504 ec_key_simple_check_key,
1505 ec_key_simple_generate_public_key,
1506 0, /* keycopy */
1507 0, /* keyfinish */
1508 ecdh_simple_compute_key
1509 };
1510
1511 return &ret;
1512 }
A mirror of the official openssl repository