1 /* crypto/ec/ec_mult.c */
3 * Originally written by Bodo Moeller and Nils Larsch for the OpenSSL project.
5 /* ====================================================================
6 * Copyright (c) 1998-2007 The OpenSSL Project. All rights reserved.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in
17 * the documentation and/or other materials provided with the
20 * 3. All advertising materials mentioning features or use of this
21 * software must display the following acknowledgment:
22 * "This product includes software developed by the OpenSSL Project
23 * for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
25 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
26 * endorse or promote products derived from this software without
27 * prior written permission. For written permission, please contact
28 * openssl-core@openssl.org.
30 * 5. Products derived from this software may not be called "OpenSSL"
31 * nor may "OpenSSL" appear in their names without prior written
32 * permission of the OpenSSL Project.
34 * 6. Redistributions of any form whatsoever must retain the following
36 * "This product includes software developed by the OpenSSL Project
37 * for use in the OpenSSL Toolkit (http://www.openssl.org/)"
39 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
40 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
41 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
42 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
43 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
44 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
45 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
46 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
48 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
49 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
50 * OF THE POSSIBILITY OF SUCH DAMAGE.
51 * ====================================================================
53 * This product includes cryptographic software written by Eric Young
54 * (eay@cryptsoft.com). This product includes software written by Tim
55 * Hudson (tjh@cryptsoft.com).
58 /* ====================================================================
59 * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
60 * Portions of this software developed by SUN MICROSYSTEMS, INC.,
61 * and contributed to the OpenSSL project.
66 #include <openssl/err.h>
72 * This file implements the wNAF-based interleaving multi-exponentation method
73 * (<URL:http://www.informatik.tu-darmstadt.de/TI/Mitarbeiter/moeller.html#multiexp>);
74 * for multiplication with precomputation, we use wNAF splitting
75 * (<URL:http://www.informatik.tu-darmstadt.de/TI/Mitarbeiter/moeller.html#fastexp>).
81 /* structure for precomputed multiples of the generator */
82 typedef struct ec_pre_comp_st
{
83 const EC_GROUP
*group
; /* parent EC_GROUP object */
84 size_t blocksize
; /* block size for wNAF splitting */
85 size_t numblocks
; /* max. number of blocks for which we have precomputation */
86 size_t w
; /* window size */
87 EC_POINT
**points
; /* array with pre-calculated multiples of generator:
88 * 'num' pointers to EC_POINT objects followed by a NULL */
89 size_t num
; /* numblocks * 2^(w-1) */
93 /* functions to manage EC_PRE_COMP within the EC_GROUP extra_data framework */
94 static void *ec_pre_comp_dup(void *);
95 static void ec_pre_comp_free(void *);
96 static void ec_pre_comp_clear_free(void *);
98 static EC_PRE_COMP
*ec_pre_comp_new(const EC_GROUP
*group
)
100 EC_PRE_COMP
*ret
= NULL
;
105 ret
= (EC_PRE_COMP
*)OPENSSL_malloc(sizeof(EC_PRE_COMP
));
108 ECerr(EC_F_EC_PRE_COMP_NEW
, ERR_R_MALLOC_FAILURE
);
112 ret
->blocksize
= 8; /* default */
114 ret
->w
= 4; /* default */
121 static void *ec_pre_comp_dup(void *src_
)
123 EC_PRE_COMP
*src
= src_
;
125 /* no need to actually copy, these objects never change! */
127 CRYPTO_add(&src
->references
, 1, CRYPTO_LOCK_EC_PRE_COMP
);
132 static void ec_pre_comp_free(void *pre_
)
135 EC_PRE_COMP
*pre
= pre_
;
140 i
= CRYPTO_add(&pre
->references
, -1, CRYPTO_LOCK_EC_PRE_COMP
);
148 for (p
= pre
->points
; *p
!= NULL
; p
++)
150 OPENSSL_free(pre
->points
);
155 static void ec_pre_comp_clear_free(void *pre_
)
158 EC_PRE_COMP
*pre
= pre_
;
163 i
= CRYPTO_add(&pre
->references
, -1, CRYPTO_LOCK_EC_PRE_COMP
);
171 for (p
= pre
->points
; *p
!= NULL
; p
++)
172 EC_POINT_clear_free(*p
);
173 OPENSSL_cleanse(pre
->points
, sizeof pre
->points
);
174 OPENSSL_free(pre
->points
);
176 OPENSSL_cleanse(pre
, sizeof pre
);
183 /* Determine the modified width-(w+1) Non-Adjacent Form (wNAF) of 'scalar'.
184 * This is an array r[] of values that are either zero or odd with an
185 * absolute value less than 2^w satisfying
186 * scalar = \sum_j r[j]*2^j
187 * where at most one of any w+1 consecutive digits is non-zero
188 * with the exception that the most significant digit may be only
189 * w-1 zeros away from that next non-zero digit.
191 static signed char *compute_wNAF(const BIGNUM
*scalar
, int w
, size_t *ret_len
)
195 signed char *r
= NULL
;
197 int bit
, next_bit
, mask
;
200 if (BN_is_zero(scalar
))
202 r
= OPENSSL_malloc(1);
205 ECerr(EC_F_COMPUTE_WNAF
, ERR_R_MALLOC_FAILURE
);
213 if (w
<= 0 || w
> 7) /* 'signed char' can represent integers with absolute values less than 2^7 */
215 ECerr(EC_F_COMPUTE_WNAF
, ERR_R_INTERNAL_ERROR
);
218 bit
= 1 << w
; /* at most 128 */
219 next_bit
= bit
<< 1; /* at most 256 */
220 mask
= next_bit
- 1; /* at most 255 */
222 if (BN_is_negative(scalar
))
227 len
= BN_num_bits(scalar
);
228 r
= OPENSSL_malloc(len
+ 1); /* modified wNAF may be one digit longer than binary representation
229 * (*ret_len will be set to the actual length, i.e. at most
230 * BN_num_bits(scalar) + 1) */
233 ECerr(EC_F_COMPUTE_WNAF
, ERR_R_MALLOC_FAILURE
);
237 if (scalar
->d
== NULL
|| scalar
->top
== 0)
239 ECerr(EC_F_COMPUTE_WNAF
, ERR_R_INTERNAL_ERROR
);
242 window_val
= scalar
->d
[0] & mask
;
244 while ((window_val
!= 0) || (j
+ w
+ 1 < len
)) /* if j+w+1 >= len, window_val will not increase */
248 /* 0 <= window_val <= 2^(w+1) */
252 /* 0 < window_val < 2^(w+1) */
254 if (window_val
& bit
)
256 digit
= window_val
- next_bit
; /* -2^w < digit < 0 */
258 #if 1 /* modified wNAF */
259 if (j
+ w
+ 1 >= len
)
261 /* special case for generating modified wNAFs:
262 * no new bits will be added into window_val,
263 * so using a positive digit here will decrease
264 * the total length of the representation */
266 digit
= window_val
& (mask
>> 1); /* 0 < digit < 2^w */
272 digit
= window_val
; /* 0 < digit < 2^w */
275 if (digit
<= -bit
|| digit
>= bit
|| !(digit
& 1))
277 ECerr(EC_F_COMPUTE_WNAF
, ERR_R_INTERNAL_ERROR
);
283 /* now window_val is 0 or 2^(w+1) in standard wNAF generation;
284 * for modified window NAFs, it may also be 2^w
286 if (window_val
!= 0 && window_val
!= next_bit
&& window_val
!= bit
)
288 ECerr(EC_F_COMPUTE_WNAF
, ERR_R_INTERNAL_ERROR
);
293 r
[j
++] = sign
* digit
;
296 window_val
+= bit
* BN_is_bit_set(scalar
, j
+ w
);
298 if (window_val
> next_bit
)
300 ECerr(EC_F_COMPUTE_WNAF
, ERR_R_INTERNAL_ERROR
);
307 ECerr(EC_F_COMPUTE_WNAF
, ERR_R_INTERNAL_ERROR
);
325 /* TODO: table should be optimised for the wNAF-based implementation,
326 * sometimes smaller windows will give better performance
327 * (thus the boundaries should be increased)
329 #define EC_window_bits_for_scalar_size(b) \
339 * \sum scalars[i]*points[i],
342 * in the addition if scalar != NULL
344 int ec_wNAF_mul(const EC_GROUP
*group
, EC_POINT
*r
, const BIGNUM
*scalar
,
345 size_t num
, const EC_POINT
*points
[], const BIGNUM
*scalars
[], BN_CTX
*ctx
)
347 BN_CTX
*new_ctx
= NULL
;
348 const EC_POINT
*generator
= NULL
;
349 EC_POINT
*tmp
= NULL
;
351 size_t blocksize
= 0, numblocks
= 0; /* for wNAF splitting */
352 size_t pre_points_per_block
= 0;
355 int r_is_inverted
= 0;
356 int r_is_at_infinity
= 1;
357 size_t *wsize
= NULL
; /* individual window sizes */
358 signed char **wNAF
= NULL
; /* individual wNAFs */
359 size_t *wNAF_len
= NULL
;
362 EC_POINT
**val
= NULL
; /* precomputation */
364 EC_POINT
***val_sub
= NULL
; /* pointers to sub-arrays of 'val' or 'pre_comp->points' */
365 const EC_PRE_COMP
*pre_comp
= NULL
;
366 int num_scalar
= 0; /* flag: will be set to 1 if 'scalar' must be treated like other scalars,
367 * i.e. precomputation is not available */
370 if (group
->meth
!= r
->meth
)
372 ECerr(EC_F_EC_WNAF_MUL
, EC_R_INCOMPATIBLE_OBJECTS
);
376 if ((scalar
== NULL
) && (num
== 0))
378 return EC_POINT_set_to_infinity(group
, r
);
381 for (i
= 0; i
< num
; i
++)
383 if (group
->meth
!= points
[i
]->meth
)
385 ECerr(EC_F_EC_WNAF_MUL
, EC_R_INCOMPATIBLE_OBJECTS
);
392 ctx
= new_ctx
= BN_CTX_new();
399 generator
= EC_GROUP_get0_generator(group
);
400 if (generator
== NULL
)
402 ECerr(EC_F_EC_WNAF_MUL
, EC_R_UNDEFINED_GENERATOR
);
406 /* look if we can use precomputed multiples of generator */
408 pre_comp
= EC_EX_DATA_get_data(group
->extra_data
, ec_pre_comp_dup
, ec_pre_comp_free
, ec_pre_comp_clear_free
);
410 if (pre_comp
&& pre_comp
->numblocks
&& (EC_POINT_cmp(group
, generator
, pre_comp
->points
[0], ctx
) == 0))
412 blocksize
= pre_comp
->blocksize
;
414 /* determine maximum number of blocks that wNAF splitting may yield
415 * (NB: maximum wNAF length is bit length plus one) */
416 numblocks
= (BN_num_bits(scalar
) / blocksize
) + 1;
418 /* we cannot use more blocks than we have precomputation for */
419 if (numblocks
> pre_comp
->numblocks
)
420 numblocks
= pre_comp
->numblocks
;
422 pre_points_per_block
= 1u << (pre_comp
->w
- 1);
424 /* check that pre_comp looks sane */
425 if (pre_comp
->num
!= (pre_comp
->numblocks
* pre_points_per_block
))
427 ECerr(EC_F_EC_WNAF_MUL
, ERR_R_INTERNAL_ERROR
);
433 /* can't use precomputation */
436 num_scalar
= 1; /* treat 'scalar' like 'num'-th element of 'scalars' */
440 totalnum
= num
+ numblocks
;
442 wsize
= OPENSSL_malloc(totalnum
* sizeof wsize
[0]);
443 wNAF_len
= OPENSSL_malloc(totalnum
* sizeof wNAF_len
[0]);
444 wNAF
= OPENSSL_malloc((totalnum
+ 1) * sizeof wNAF
[0]); /* includes space for pivot */
445 val_sub
= OPENSSL_malloc(totalnum
* sizeof val_sub
[0]);
447 if (!wsize
|| !wNAF_len
|| !wNAF
|| !val_sub
)
449 ECerr(EC_F_EC_WNAF_MUL
, ERR_R_MALLOC_FAILURE
);
453 wNAF
[0] = NULL
; /* preliminary pivot */
455 /* num_val will be the total number of temporarily precomputed points */
458 for (i
= 0; i
< num
+ num_scalar
; i
++)
462 bits
= i
< num
? BN_num_bits(scalars
[i
]) : BN_num_bits(scalar
);
463 wsize
[i
] = EC_window_bits_for_scalar_size(bits
);
464 num_val
+= 1u << (wsize
[i
] - 1);
465 wNAF
[i
+ 1] = NULL
; /* make sure we always have a pivot */
466 wNAF
[i
] = compute_wNAF((i
< num
? scalars
[i
] : scalar
), wsize
[i
], &wNAF_len
[i
]);
469 if (wNAF_len
[i
] > max_len
)
470 max_len
= wNAF_len
[i
];
475 /* we go here iff scalar != NULL */
477 if (pre_comp
== NULL
)
481 ECerr(EC_F_EC_WNAF_MUL
, ERR_R_INTERNAL_ERROR
);
484 /* we have already generated a wNAF for 'scalar' */
488 signed char *tmp_wNAF
= NULL
;
493 ECerr(EC_F_EC_WNAF_MUL
, ERR_R_INTERNAL_ERROR
);
497 /* use the window size for which we have precomputation */
498 wsize
[num
] = pre_comp
->w
;
499 tmp_wNAF
= compute_wNAF(scalar
, wsize
[num
], &tmp_len
);
503 if (tmp_len
<= max_len
)
505 /* One of the other wNAFs is at least as long
506 * as the wNAF belonging to the generator,
507 * so wNAF splitting will not buy us anything. */
510 totalnum
= num
+ 1; /* don't use wNAF splitting */
511 wNAF
[num
] = tmp_wNAF
;
512 wNAF
[num
+ 1] = NULL
;
513 wNAF_len
[num
] = tmp_len
;
514 if (tmp_len
> max_len
)
516 /* pre_comp->points starts with the points that we need here: */
517 val_sub
[num
] = pre_comp
->points
;
521 /* don't include tmp_wNAF directly into wNAF array
522 * - use wNAF splitting and include the blocks */
525 EC_POINT
**tmp_points
;
527 if (tmp_len
< numblocks
* blocksize
)
529 /* possibly we can do with fewer blocks than estimated */
530 numblocks
= (tmp_len
+ blocksize
- 1) / blocksize
;
531 if (numblocks
> pre_comp
->numblocks
)
533 ECerr(EC_F_EC_WNAF_MUL
, ERR_R_INTERNAL_ERROR
);
536 totalnum
= num
+ numblocks
;
539 /* split wNAF in 'numblocks' parts */
541 tmp_points
= pre_comp
->points
;
543 for (i
= num
; i
< totalnum
; i
++)
545 if (i
< totalnum
- 1)
547 wNAF_len
[i
] = blocksize
;
548 if (tmp_len
< blocksize
)
550 ECerr(EC_F_EC_WNAF_MUL
, ERR_R_INTERNAL_ERROR
);
553 tmp_len
-= blocksize
;
556 /* last block gets whatever is left
557 * (this could be more or less than 'blocksize'!) */
558 wNAF_len
[i
] = tmp_len
;
561 wNAF
[i
] = OPENSSL_malloc(wNAF_len
[i
]);
564 ECerr(EC_F_EC_WNAF_MUL
, ERR_R_MALLOC_FAILURE
);
565 OPENSSL_free(tmp_wNAF
);
568 memcpy(wNAF
[i
], pp
, wNAF_len
[i
]);
569 if (wNAF_len
[i
] > max_len
)
570 max_len
= wNAF_len
[i
];
572 if (*tmp_points
== NULL
)
574 ECerr(EC_F_EC_WNAF_MUL
, ERR_R_INTERNAL_ERROR
);
575 OPENSSL_free(tmp_wNAF
);
578 val_sub
[i
] = tmp_points
;
579 tmp_points
+= pre_points_per_block
;
582 OPENSSL_free(tmp_wNAF
);
587 /* All points we precompute now go into a single array 'val'.
588 * 'val_sub[i]' is a pointer to the subarray for the i-th point,
589 * or to a subarray of 'pre_comp->points' if we already have precomputation. */
590 val
= OPENSSL_malloc((num_val
+ 1) * sizeof val
[0]);
593 ECerr(EC_F_EC_WNAF_MUL
, ERR_R_MALLOC_FAILURE
);
596 val
[num_val
] = NULL
; /* pivot element */
598 /* allocate points for precomputation */
600 for (i
= 0; i
< num
+ num_scalar
; i
++)
603 for (j
= 0; j
< (1u << (wsize
[i
] - 1)); j
++)
605 *v
= EC_POINT_new(group
);
606 if (*v
== NULL
) goto err
;
610 if (!(v
== val
+ num_val
))
612 ECerr(EC_F_EC_WNAF_MUL
, ERR_R_INTERNAL_ERROR
);
616 if (!(tmp
= EC_POINT_new(group
)))
619 /* prepare precomputed values:
620 * val_sub[i][0] := points[i]
621 * val_sub[i][1] := 3 * points[i]
622 * val_sub[i][2] := 5 * points[i]
625 for (i
= 0; i
< num
+ num_scalar
; i
++)
629 if (!EC_POINT_copy(val_sub
[i
][0], points
[i
])) goto err
;
633 if (!EC_POINT_copy(val_sub
[i
][0], generator
)) goto err
;
638 if (!EC_POINT_dbl(group
, tmp
, val_sub
[i
][0], ctx
)) goto err
;
639 for (j
= 1; j
< (1u << (wsize
[i
] - 1)); j
++)
641 if (!EC_POINT_add(group
, val_sub
[i
][j
], val_sub
[i
][j
- 1], tmp
, ctx
)) goto err
;
646 #if 1 /* optional; EC_window_bits_for_scalar_size assumes we do this step */
647 if (!EC_POINTs_make_affine(group
, num_val
, val
, ctx
))
651 r_is_at_infinity
= 1;
653 for (k
= max_len
- 1; k
>= 0; k
--)
655 if (!r_is_at_infinity
)
657 if (!EC_POINT_dbl(group
, r
, r
, ctx
)) goto err
;
660 for (i
= 0; i
< totalnum
; i
++)
662 if (wNAF_len
[i
] > (size_t)k
)
664 int digit
= wNAF
[i
][k
];
674 if (is_neg
!= r_is_inverted
)
676 if (!r_is_at_infinity
)
678 if (!EC_POINT_invert(group
, r
, ctx
)) goto err
;
680 r_is_inverted
= !r_is_inverted
;
685 if (r_is_at_infinity
)
687 if (!EC_POINT_copy(r
, val_sub
[i
][digit
>> 1])) goto err
;
688 r_is_at_infinity
= 0;
692 if (!EC_POINT_add(group
, r
, r
, val_sub
[i
][digit
>> 1], ctx
)) goto err
;
699 if (r_is_at_infinity
)
701 if (!EC_POINT_set_to_infinity(group
, r
)) goto err
;
706 if (!EC_POINT_invert(group
, r
, ctx
)) goto err
;
713 BN_CTX_free(new_ctx
);
718 if (wNAF_len
!= NULL
)
719 OPENSSL_free(wNAF_len
);
724 for (w
= wNAF
; *w
!= NULL
; w
++)
731 for (v
= val
; *v
!= NULL
; v
++)
732 EC_POINT_clear_free(*v
);
738 OPENSSL_free(val_sub
);
744 /* ec_wNAF_precompute_mult()
745 * creates an EC_PRE_COMP object with preprecomputed multiples of the generator
746 * for use with wNAF splitting as implemented in ec_wNAF_mul().
748 * 'pre_comp->points' is an array of multiples of the generator
749 * of the following form:
750 * points[0] = generator;
751 * points[1] = 3 * generator;
753 * points[2^(w-1)-1] = (2^(w-1)-1) * generator;
754 * points[2^(w-1)] = 2^blocksize * generator;
755 * points[2^(w-1)+1] = 3 * 2^blocksize * generator;
757 * points[2^(w-1)*(numblocks-1)-1] = (2^(w-1)) * 2^(blocksize*(numblocks-2)) * generator
758 * points[2^(w-1)*(numblocks-1)] = 2^(blocksize*(numblocks-1)) * generator
760 * points[2^(w-1)*numblocks-1] = (2^(w-1)) * 2^(blocksize*(numblocks-1)) * generator
761 * points[2^(w-1)*numblocks] = NULL
763 int ec_wNAF_precompute_mult(EC_GROUP
*group
, BN_CTX
*ctx
)
765 const EC_POINT
*generator
;
766 EC_POINT
*tmp_point
= NULL
, *base
= NULL
, **var
;
767 BN_CTX
*new_ctx
= NULL
;
769 size_t i
, bits
, w
, pre_points_per_block
, blocksize
, numblocks
, num
;
770 EC_POINT
**points
= NULL
;
771 EC_PRE_COMP
*pre_comp
;
774 /* if there is an old EC_PRE_COMP object, throw it away */
775 EC_EX_DATA_free_data(&group
->extra_data
, ec_pre_comp_dup
, ec_pre_comp_free
, ec_pre_comp_clear_free
);
777 if ((pre_comp
= ec_pre_comp_new(group
)) == NULL
)
780 generator
= EC_GROUP_get0_generator(group
);
781 if (generator
== NULL
)
783 ECerr(EC_F_EC_WNAF_PRECOMPUTE_MULT
, EC_R_UNDEFINED_GENERATOR
);
789 ctx
= new_ctx
= BN_CTX_new();
795 order
= BN_CTX_get(ctx
);
796 if (order
== NULL
) goto err
;
798 if (!EC_GROUP_get_order(group
, order
, ctx
)) goto err
;
799 if (BN_is_zero(order
))
801 ECerr(EC_F_EC_WNAF_PRECOMPUTE_MULT
, EC_R_UNKNOWN_ORDER
);
805 bits
= BN_num_bits(order
);
806 /* The following parameters mean we precompute (approximately)
809 * TBD: The combination 8, 4 is perfect for 160 bits; for other
810 * bit lengths, other parameter combinations might provide better
815 if (EC_window_bits_for_scalar_size(bits
) > w
)
817 /* let's not make the window too small ... */
818 w
= EC_window_bits_for_scalar_size(bits
);
821 numblocks
= (bits
+ blocksize
- 1) / blocksize
; /* max. number of blocks to use for wNAF splitting */
823 pre_points_per_block
= 1u << (w
- 1);
824 num
= pre_points_per_block
* numblocks
; /* number of points to compute and store */
826 points
= OPENSSL_malloc(sizeof (EC_POINT
*)*(num
+ 1));
829 ECerr(EC_F_EC_WNAF_PRECOMPUTE_MULT
, ERR_R_MALLOC_FAILURE
);
834 var
[num
] = NULL
; /* pivot */
835 for (i
= 0; i
< num
; i
++)
837 if ((var
[i
] = EC_POINT_new(group
)) == NULL
)
839 ECerr(EC_F_EC_WNAF_PRECOMPUTE_MULT
, ERR_R_MALLOC_FAILURE
);
844 if (!(tmp_point
= EC_POINT_new(group
)) || !(base
= EC_POINT_new(group
)))
846 ECerr(EC_F_EC_WNAF_PRECOMPUTE_MULT
, ERR_R_MALLOC_FAILURE
);
850 if (!EC_POINT_copy(base
, generator
))
853 /* do the precomputation */
854 for (i
= 0; i
< numblocks
; i
++)
858 if (!EC_POINT_dbl(group
, tmp_point
, base
, ctx
))
861 if (!EC_POINT_copy(*var
++, base
))
864 for (j
= 1; j
< pre_points_per_block
; j
++, var
++)
866 /* calculate odd multiples of the current base point */
867 if (!EC_POINT_add(group
, *var
, tmp_point
, *(var
- 1), ctx
))
871 if (i
< numblocks
- 1)
873 /* get the next base (multiply current one by 2^blocksize) */
878 ECerr(EC_F_EC_WNAF_PRECOMPUTE_MULT
, ERR_R_INTERNAL_ERROR
);
882 if (!EC_POINT_dbl(group
, base
, tmp_point
, ctx
))
884 for (k
= 2; k
< blocksize
; k
++)
886 if (!EC_POINT_dbl(group
,base
,base
,ctx
))
892 if (!EC_POINTs_make_affine(group
, num
, points
, ctx
))
895 pre_comp
->group
= group
;
896 pre_comp
->blocksize
= blocksize
;
897 pre_comp
->numblocks
= numblocks
;
899 pre_comp
->points
= points
;
903 if (!EC_EX_DATA_set_data(&group
->extra_data
, pre_comp
,
904 ec_pre_comp_dup
, ec_pre_comp_free
, ec_pre_comp_clear_free
))
913 BN_CTX_free(new_ctx
);
915 ec_pre_comp_free(pre_comp
);
920 for (p
= points
; *p
!= NULL
; p
++)
922 OPENSSL_free(points
);
925 EC_POINT_free(tmp_point
);
932 int ec_wNAF_have_precompute_mult(const EC_GROUP
*group
)
934 if (EC_EX_DATA_get_data(group
->extra_data
, ec_pre_comp_dup
, ec_pre_comp_free
, ec_pre_comp_clear_free
) != NULL
)