1 /* crypto/ec/ec_mult.c */
3 * Originally written by Bodo Moeller and Nils Larsch for the OpenSSL project.
5 /* ====================================================================
6 * Copyright (c) 1998-2003 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) */
92 /* functions to manage EC_PRE_COMP within the EC_GROUP extra_data framework */
93 static void *ec_pre_comp_dup(void *);
94 static void ec_pre_comp_free(void *);
95 static void ec_pre_comp_clear_free(void *);
97 static EC_PRE_COMP
*ec_pre_comp_new(const EC_GROUP
*group
)
99 EC_PRE_COMP
*ret
= NULL
;
104 ret
= (EC_PRE_COMP
*)OPENSSL_malloc(sizeof(EC_PRE_COMP
));
108 ret
->blocksize
= 8; /* default */
110 ret
->w
= 4; /* default */
116 static void *ec_pre_comp_dup(void *src_
)
118 const EC_PRE_COMP
*src
= src_
;
119 EC_PRE_COMP
*ret
= NULL
;
121 ret
= ec_pre_comp_new(src
->group
);
124 ret
->blocksize
= src
->blocksize
;
125 ret
->numblocks
= src
->numblocks
;
131 EC_POINT
**src_var
, **dest_var
;
133 ret
->points
= (EC_POINT
**)OPENSSL_malloc((src
->num
+ 1) * sizeof(EC_POINT
*));
136 ec_pre_comp_free(ret
);
140 for (dest_var
= ret
->points
, src_var
= src
->points
; *src_var
!= NULL
; src_var
++, dest_var
++)
142 *dest_var
= EC_POINT_dup(*src_var
, src
->group
);
143 if (*dest_var
== NULL
)
145 ec_pre_comp_free(ret
);
151 ret
->points
[ret
->num
] = NULL
;
152 if (ret
->num
!= src
->num
)
154 ec_pre_comp_free(ret
);
155 ECerr(EC_F_EC_PRE_COMP_DUP
, ERR_R_INTERNAL_ERROR
);
163 static void ec_pre_comp_free(void *pre_
)
165 EC_PRE_COMP
*pre
= pre_
;
173 for (var
= pre
->points
; *var
!= NULL
; var
++)
175 OPENSSL_free(pre
->points
);
180 static void ec_pre_comp_clear_free(void *pre_
)
182 EC_PRE_COMP
*pre
= pre_
;
190 for (p
= pre
->points
; *p
!= NULL
; p
++)
191 EC_POINT_clear_free(*p
);
192 OPENSSL_cleanse(pre
->points
, sizeof pre
->points
);
193 OPENSSL_free(pre
->points
);
195 OPENSSL_cleanse(pre
, sizeof pre
);
202 /* Determine the modified width-(w+1) Non-Adjacent Form (wNAF) of 'scalar'.
203 * This is an array r[] of values that are either zero or odd with an
204 * absolute value less than 2^w satisfying
205 * scalar = \sum_j r[j]*2^j
206 * where at most one of any w+1 consecutive digits is non-zero
207 * with the exception that the most significant digit may be only
208 * w-1 zeros away from that next non-zero digit.
210 static signed char *compute_wNAF(const BIGNUM
*scalar
, int w
, size_t *ret_len
)
214 signed char *r
= NULL
;
216 int bit
, next_bit
, mask
;
219 if (w
<= 0 || w
> 7) /* 'signed char' can represent integers with absolute values less than 2^7 */
221 ECerr(EC_F_COMPUTE_WNAF
, ERR_R_INTERNAL_ERROR
);
224 bit
= 1 << w
; /* at most 128 */
225 next_bit
= bit
<< 1; /* at most 256 */
226 mask
= next_bit
- 1; /* at most 255 */
228 if (BN_get_sign(scalar
))
233 len
= BN_num_bits(scalar
);
234 r
= OPENSSL_malloc(len
+ 1); /* modified wNAF may be one digit longer than binary representation
235 * (*ret_len will be set to the actual length, i.e. at most
236 * BN_num_bits(scalar) + 1) */
237 if (r
== NULL
) goto err
;
239 if (scalar
->d
== NULL
|| scalar
->top
== 0)
241 ECerr(EC_F_COMPUTE_WNAF
, ERR_R_INTERNAL_ERROR
);
244 window_val
= scalar
->d
[0] & mask
;
246 while ((window_val
!= 0) || (j
+ w
+ 1 < len
)) /* if j+w+1 >= len, window_val will not increase */
250 /* 0 <= window_val <= 2^(w+1) */
254 /* 0 < window_val < 2^(w+1) */
256 if (window_val
& bit
)
258 digit
= window_val
- next_bit
; /* -2^w < digit < 0 */
260 #if 1 /* modified wNAF */
261 if (j
+ w
+ 1 >= len
)
263 /* special case for generating modified wNAFs:
264 * no new bits will be added into window_val,
265 * so using a positive digit here will decrease
266 * the total length of the representation */
268 digit
= window_val
& (mask
>> 1); /* 0 < digit < 2^w */
274 digit
= window_val
; /* 0 < digit < 2^w */
277 if (digit
<= -bit
|| digit
>= bit
|| !(digit
& 1))
279 ECerr(EC_F_COMPUTE_WNAF
, ERR_R_INTERNAL_ERROR
);
285 /* now window_val is 0 or 2^(w+1) in standard wNAF generation;
286 * for modified window NAFs, it may also be 2^w
288 if (window_val
!= 0 && window_val
!= next_bit
&& window_val
!= bit
)
290 ECerr(EC_F_COMPUTE_WNAF
, ERR_R_INTERNAL_ERROR
);
295 r
[j
++] = sign
* digit
;
298 window_val
+= bit
* BN_is_bit_set(scalar
, j
+ w
);
300 if (window_val
> next_bit
)
302 ECerr(EC_F_COMPUTE_WNAF
, ERR_R_INTERNAL_ERROR
);
309 ECerr(EC_F_COMPUTE_WNAF
, ERR_R_INTERNAL_ERROR
);
327 /* TODO: table should be optimised for the wNAF-based implementation,
328 * sometimes smaller windows will give better performance
329 * (thus the boundaries should be increased)
331 #define EC_window_bits_for_scalar_size(b) \
340 * \sum scalars[i]*points[i],
343 * in the addition if scalar != NULL
345 int ec_wNAF_mul(const EC_GROUP
*group
, EC_POINT
*r
, const BIGNUM
*scalar
,
346 size_t num
, const EC_POINT
*points
[], const BIGNUM
*scalars
[], BN_CTX
*ctx
)
348 BN_CTX
*new_ctx
= NULL
;
349 EC_POINT
*generator
= NULL
;
350 EC_POINT
*tmp
= NULL
;
352 size_t blocksize
= 0, numblocks
= 0; /* for wNAF splitting */
353 size_t pre_points_per_block
= 0;
356 int r_is_inverted
= 0;
357 int r_is_at_infinity
= 1;
358 size_t *wsize
= NULL
; /* individual window sizes */
359 signed char **wNAF
= NULL
; /* individual wNAFs */
360 size_t *wNAF_len
= NULL
;
363 EC_POINT
**val
= NULL
; /* precomputation */
365 EC_POINT
***val_sub
= NULL
; /* pointers to sub-arrays of 'val' or 'pre_comp->points' */
366 EC_PRE_COMP
*pre_comp
= NULL
;
367 int num_scalar
= 0; /* flag: will be set to 1 if 'scalar' must be treated like other scalars,
368 * i.e. precomputation is not available */
371 if (group
->meth
!= r
->meth
)
373 ECerr(EC_F_EC_WNAF_MUL
, EC_R_INCOMPATIBLE_OBJECTS
);
377 if ((scalar
== NULL
) && (num
== 0))
379 return EC_POINT_set_to_infinity(group
, r
);
382 for (i
= 0; i
< num
; i
++)
384 if (group
->meth
!= points
[i
]->meth
)
386 ECerr(EC_F_EC_WNAF_MUL
, EC_R_INCOMPATIBLE_OBJECTS
);
393 ctx
= new_ctx
= BN_CTX_new();
400 generator
= EC_GROUP_get0_generator(group
);
401 if (generator
== NULL
)
403 ECerr(EC_F_EC_WNAF_MUL
, EC_R_UNDEFINED_GENERATOR
);
407 /* look if we can use precomputed multiples of generator */
409 pre_comp
= EC_GROUP_get_extra_data(group
, ec_pre_comp_dup
, ec_pre_comp_free
, ec_pre_comp_clear_free
);
411 if (pre_comp
&& pre_comp
->numblocks
&& (EC_POINT_cmp(group
, generator
, pre_comp
->points
[0], ctx
) == 0))
413 blocksize
= pre_comp
->blocksize
;
415 /* determine maximum number of blocks that wNAF splitting may yield
416 * (NB: maximum wNAF length is bit length plus one) */
417 numblocks
= (BN_num_bits(scalar
) / blocksize
) + 1;
419 /* we cannot use more blocks than we have precomputation for */
420 if (numblocks
> pre_comp
->numblocks
)
421 numblocks
= pre_comp
->numblocks
;
423 pre_points_per_block
= 1u << (pre_comp
->w
- 1);
425 /* check that pre_comp looks sane */
426 if (pre_comp
->num
!= (pre_comp
->numblocks
* pre_points_per_block
))
428 ECerr(EC_F_EC_WNAF_MUL
, ERR_R_INTERNAL_ERROR
);
434 /* can't use precomputation */
437 num_scalar
= 1; /* treat 'scalar' like 'num'-th element of 'scalars' */
441 totalnum
= num
+ numblocks
;
443 wsize
= OPENSSL_malloc(totalnum
* sizeof wsize
[0]);
444 wNAF_len
= OPENSSL_malloc(totalnum
* sizeof wNAF_len
[0]);
445 wNAF
= OPENSSL_malloc((totalnum
+ 1) * sizeof wNAF
[0]); /* includes space for pivot */
446 val_sub
= OPENSSL_malloc(totalnum
* sizeof val_sub
[0]);
448 if (!wsize
|| !wNAF_len
|| !wNAF
|| !val_sub
)
451 wNAF
[0] = NULL
; /* preliminary pivot */
453 /* num_val will be the total number of temporarily precomputed points */
456 for (i
= 0; i
< num
+ num_scalar
; i
++)
460 bits
= i
< num
? BN_num_bits(scalars
[i
]) : BN_num_bits(scalar
);
461 wsize
[i
] = EC_window_bits_for_scalar_size(bits
);
462 num_val
+= 1u << (wsize
[i
] - 1);
463 wNAF
[i
+ 1] = NULL
; /* make sure we always have a pivot */
464 wNAF
[i
] = compute_wNAF((i
< num
? scalars
[i
] : scalar
), wsize
[i
], &wNAF_len
[i
]);
467 if (wNAF_len
[i
] > max_len
)
468 max_len
= wNAF_len
[i
];
473 /* we go here iff scalar != NULL */
475 if (pre_comp
== NULL
)
479 ECerr(EC_F_EC_WNAF_MUL
, ERR_R_INTERNAL_ERROR
);
482 /* we have already generated a wNAF for 'scalar' */
486 signed char *tmp_wNAF
= NULL
;
491 ECerr(EC_F_EC_WNAF_MUL
, ERR_R_INTERNAL_ERROR
);
495 /* use the window size for which we have precomputation */
496 wsize
[num
] = pre_comp
->w
;
497 tmp_wNAF
= compute_wNAF(scalar
, wsize
[num
], &tmp_len
);
501 if (tmp_len
<= max_len
)
503 /* One of the other wNAFs is at least as long
504 * as the wNAF belonging to the generator,
505 * so wNAF splitting will not buy us anything. */
508 totalnum
= num
+ 1; /* don't use wNAF splitting */
509 wNAF
[num
] = tmp_wNAF
;
510 wNAF
[num
+ 1] = NULL
;
511 wNAF_len
[num
] = tmp_len
;
512 if (tmp_len
> max_len
)
514 /* pre_comp->points starts with the points that we need here: */
515 val_sub
[num
] = pre_comp
->points
;
519 /* don't include tmp_wNAF directly into wNAF array
520 * - use wNAF splitting and include the blocks */
523 EC_POINT
**tmp_points
;
525 if (tmp_len
< numblocks
* blocksize
)
527 /* possibly we can do with fewer blocks than estimated */
528 numblocks
= (tmp_len
+ blocksize
- 1) / blocksize
;
529 if (numblocks
> pre_comp
->numblocks
)
531 ECerr(EC_F_EC_WNAF_MUL
, ERR_R_INTERNAL_ERROR
);
534 totalnum
= num
+ numblocks
;
537 /* split wNAF in 'numblocks' parts */
539 tmp_points
= pre_comp
->points
;
541 for (i
= num
; i
< totalnum
; i
++)
543 if (i
< totalnum
- 1)
545 wNAF_len
[i
] = blocksize
;
546 if (tmp_len
< blocksize
)
548 ECerr(EC_F_EC_WNAF_MUL
, ERR_R_INTERNAL_ERROR
);
551 tmp_len
-= blocksize
;
554 /* last block gets whatever is left
555 * (this could be more or less than 'blocksize'!) */
556 wNAF_len
[i
] = tmp_len
;
559 wNAF
[i
] = OPENSSL_malloc(wNAF_len
[i
]);
562 OPENSSL_free(tmp_wNAF
);
565 memcpy(wNAF
[i
], pp
, wNAF_len
[i
]);
566 if (wNAF_len
[i
] > max_len
)
567 max_len
= wNAF_len
[i
];
569 if (*tmp_points
== NULL
)
571 ECerr(EC_F_EC_WNAF_MUL
, ERR_R_INTERNAL_ERROR
);
572 OPENSSL_free(tmp_wNAF
);
575 val_sub
[i
] = tmp_points
;
576 tmp_points
+= pre_points_per_block
;
579 OPENSSL_free(tmp_wNAF
);
584 /* All points we precompute now go into a single array 'val'.
585 * 'val_sub[i]' is a pointer to the subarray for the i-th point,
586 * or to a subarray of 'pre_comp->points' if we already have precomputation. */
587 val
= OPENSSL_malloc((num_val
+ 1) * sizeof val
[0]);
588 if (val
== NULL
) goto err
;
589 val
[num_val
] = NULL
; /* pivot element */
591 /* allocate points for precomputation */
593 for (i
= 0; i
< num
+ num_scalar
; i
++)
596 for (j
= 0; j
< (1u << (wsize
[i
] - 1)); j
++)
598 *v
= EC_POINT_new(group
);
599 if (*v
== NULL
) goto err
;
603 if (!(v
== val
+ num_val
))
605 ECerr(EC_F_EC_WNAF_MUL
, ERR_R_INTERNAL_ERROR
);
609 if (!(tmp
= EC_POINT_new(group
)))
612 /* prepare precomputed values:
613 * val_sub[i][0] := points[i]
614 * val_sub[i][1] := 3 * points[i]
615 * val_sub[i][2] := 5 * points[i]
618 for (i
= 0; i
< num
+ num_scalar
; i
++)
622 if (!EC_POINT_copy(val_sub
[i
][0], points
[i
])) goto err
;
626 if (!EC_POINT_copy(val_sub
[i
][0], generator
)) goto err
;
631 if (!EC_POINT_dbl(group
, tmp
, val_sub
[i
][0], ctx
)) goto err
;
632 for (j
= 1; j
< (1u << (wsize
[i
] - 1)); j
++)
634 if (!EC_POINT_add(group
, val_sub
[i
][j
], val_sub
[i
][j
- 1], tmp
, ctx
)) goto err
;
639 #if 1 /* optional; EC_window_bits_for_scalar_size assumes we do this step */
640 if (!EC_POINTs_make_affine(group
, num_val
, val
, ctx
))
644 r_is_at_infinity
= 1;
646 for (k
= max_len
- 1; k
>= 0; k
--)
648 if (!r_is_at_infinity
)
650 if (!EC_POINT_dbl(group
, r
, r
, ctx
)) goto err
;
653 for (i
= 0; i
< totalnum
; i
++)
655 if (wNAF_len
[i
] > (size_t)k
)
657 int digit
= wNAF
[i
][k
];
667 if (is_neg
!= r_is_inverted
)
669 if (!r_is_at_infinity
)
671 if (!EC_POINT_invert(group
, r
, ctx
)) goto err
;
673 r_is_inverted
= !r_is_inverted
;
678 if (r_is_at_infinity
)
680 if (!EC_POINT_copy(r
, val_sub
[i
][digit
>> 1])) goto err
;
681 r_is_at_infinity
= 0;
685 if (!EC_POINT_add(group
, r
, r
, val_sub
[i
][digit
>> 1], ctx
)) goto err
;
692 if (r_is_at_infinity
)
694 if (!EC_POINT_set_to_infinity(group
, r
)) goto err
;
699 if (!EC_POINT_invert(group
, r
, ctx
)) goto err
;
706 BN_CTX_free(new_ctx
);
711 if (wNAF_len
!= NULL
)
712 OPENSSL_free(wNAF_len
);
717 for (w
= wNAF
; *w
!= NULL
; w
++)
724 for (v
= val
; *v
!= NULL
; v
++)
725 EC_POINT_clear_free(*v
);
731 OPENSSL_free(val_sub
);
737 /* ec_wNAF_precompute_mult()
738 * creates an EC_PRE_COMP object with preprecomputed multiples of the generator
739 * for use with wNAF splitting as implemented in ec_wNAF_mul().
741 * 'pre_comp->points' is an array of multiples of the generator
742 * of the following form:
743 * points[0] = generator;
744 * points[1] = 3 * generator;
746 * points[2^(w-1)-1] = (2^(w-1)-1) * generator;
747 * points[2^(w-1)] = 2^blocksize * generator;
748 * points[2^(w-1)+1] = 3 * 2^blocksize * generator;
750 * points[2^(w-1)*(numblocks-1)-1] = (2^(w-1)) * 2^(blocksize*(numblocks-2)) * generator
751 * points[2^(w-1)*(numblocks-1)] = 2^(blocksize*(numblocks-1)) * generator
753 * points[2^(w-1)*numblocks-1] = (2^(w-1)) * 2^(blocksize*(numblocks-1)) * generator
754 * points[2^(w-1)*numblocks] = NULL
756 int ec_wNAF_precompute_mult(EC_GROUP
*group
, BN_CTX
*ctx
)
758 const EC_POINT
*generator
;
759 EC_POINT
*tmp_point
= NULL
, *base
= NULL
, **var
;
760 BN_CTX
*new_ctx
= NULL
;
762 size_t i
, bits
, w
, pre_points_per_block
, blocksize
, numblocks
, num
;
763 EC_POINT
**points
= NULL
;
764 EC_PRE_COMP
*pre_comp
, *new_pre_comp
= NULL
;
767 pre_comp
= EC_GROUP_get_extra_data(group
, ec_pre_comp_dup
, ec_pre_comp_free
, ec_pre_comp_clear_free
);
768 if (pre_comp
== NULL
)
769 if ((pre_comp
= new_pre_comp
= ec_pre_comp_new(group
)) == NULL
)
772 generator
= EC_GROUP_get0_generator(group
);
773 if (generator
== NULL
)
775 ECerr(EC_F_EC_WNAF_PRECOMPUTE_MULT
, EC_R_UNDEFINED_GENERATOR
);
781 ctx
= new_ctx
= BN_CTX_new();
787 order
= BN_CTX_get(ctx
);
788 if (order
== NULL
) goto err
;
790 if (!EC_GROUP_get_order(group
, order
, ctx
)) goto err
;
791 if (BN_is_zero(order
))
793 ECerr(EC_F_EC_WNAF_PRECOMPUTE_MULT
, EC_R_UNKNOWN_ORDER
);
797 bits
= BN_num_bits(order
);
798 /* The following parameters mean we precompute (approximately)
801 * TBD: The combination 8, 4 is perfect for 160 bits; for other
802 * bit lengths, other parameter combinations might provide better
807 if (EC_window_bits_for_scalar_size(bits
) > w
)
809 /* let's not make the window too small ... */
810 w
= EC_window_bits_for_scalar_size(bits
);
813 numblocks
= (bits
+ blocksize
- 1) / blocksize
; /* max. number of blocks to use for wNAF splitting */
815 pre_points_per_block
= 1u << (w
- 1);
816 num
= pre_points_per_block
* numblocks
; /* number of points to compute and store */
818 points
= OPENSSL_malloc(sizeof (EC_POINT
*)*(num
+ 1));
821 ECerr(EC_F_EC_WNAF_PRECOMPUTE_MULT
, ERR_R_MALLOC_FAILURE
);
826 var
[num
] = NULL
; /* pivot */
827 for (i
= 0; i
< num
; i
++)
829 if ((var
[i
] = EC_POINT_new(group
)) == NULL
)
831 ECerr(EC_F_EC_WNAF_PRECOMPUTE_MULT
, ERR_R_MALLOC_FAILURE
);
836 if (!(tmp_point
= EC_POINT_new(group
)) || !(base
= EC_POINT_new(group
)))
838 ECerr(EC_F_EC_WNAF_PRECOMPUTE_MULT
, ERR_R_MALLOC_FAILURE
);
842 if (!EC_POINT_copy(base
, generator
))
845 /* do the precomputation */
846 for (i
= 0; i
< numblocks
; i
++)
850 if (!EC_POINT_dbl(group
, tmp_point
, base
, ctx
))
853 if (!EC_POINT_copy(*var
++, base
))
856 for (j
= 1; j
< pre_points_per_block
; j
++, var
++)
858 /* calculate odd multiples of the current base point */
859 if (!EC_POINT_add(group
, *var
, tmp_point
, *(var
- 1), ctx
))
863 if (i
< numblocks
- 1)
865 /* get the next base (multiply current one by 2^blocksize) */
870 ECerr(EC_F_EC_WNAF_PRECOMPUTE_MULT
, ERR_R_INTERNAL_ERROR
);
874 if (!EC_POINT_dbl(group
, base
, tmp_point
, ctx
))
876 for (k
= 2; k
< blocksize
; k
++)
878 if (!EC_POINT_dbl(group
,base
,base
,ctx
))
884 if (!EC_POINTs_make_affine(group
, num
, points
, ctx
))
887 pre_comp
->group
= group
;
888 pre_comp
->blocksize
= blocksize
;
889 pre_comp
->numblocks
= numblocks
;
891 if (pre_comp
->points
)
895 for (p
= pre_comp
->points
; *p
!= NULL
; p
++)
897 OPENSSL_free(pre_comp
->points
);
899 pre_comp
->points
= points
;
905 if (!EC_GROUP_set_extra_data(group
, new_pre_comp
, ec_pre_comp_dup
, ec_pre_comp_free
, ec_pre_comp_clear_free
))
914 BN_CTX_free(new_ctx
);
916 ec_pre_comp_free(new_pre_comp
);
921 for (p
= points
; *p
!= NULL
; p
++)
923 OPENSSL_free(points
);
926 EC_POINT_free(tmp_point
);
933 int ec_wNAF_have_precompute_mult(const EC_GROUP
*group
)
935 if (EC_GROUP_get_extra_data(group
, ec_pre_comp_dup
, ec_pre_comp_free
, ec_pre_comp_clear_free
) != NULL
)