1 /* crypto/bn/bn_nist.c */
3 * Written by Nils Larsch for the OpenSSL project
5 /* ====================================================================
6 * Copyright (c) 1998-2005 The OpenSSL Project. All rights reserved.
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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).
63 #define BN_NIST_192_TOP (192+BN_BITS2-1)/BN_BITS2
64 #define BN_NIST_224_TOP (224+BN_BITS2-1)/BN_BITS2
65 #define BN_NIST_256_TOP (256+BN_BITS2-1)/BN_BITS2
66 #define BN_NIST_384_TOP (384+BN_BITS2-1)/BN_BITS2
67 #define BN_NIST_521_TOP (521+BN_BITS2-1)/BN_BITS2
69 /* pre-computed tables are "carry-less" values of modulus*(i+1) */
71 static const BN_ULONG _nist_p_192[][BN_NIST_192_TOP] = {
72 {0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFEULL,0xFFFFFFFFFFFFFFFFULL},
73 {0xFFFFFFFFFFFFFFFEULL,0xFFFFFFFFFFFFFFFDULL,0xFFFFFFFFFFFFFFFFULL},
74 {0xFFFFFFFFFFFFFFFDULL,0xFFFFFFFFFFFFFFFCULL,0xFFFFFFFFFFFFFFFFULL}
76 static const BN_ULONG _nist_p_224[][BN_NIST_224_TOP] = {
77 {0x0000000000000001ULL,0xFFFFFFFF00000000ULL,
78 0xFFFFFFFFFFFFFFFFULL,0x00000000FFFFFFFFULL},
79 {0x0000000000000002ULL,0xFFFFFFFE00000000ULL,
80 0xFFFFFFFFFFFFFFFFULL,0x00000001FFFFFFFFULL} /* this one is "carry-full" */
82 static const BN_ULONG _nist_p_256[][BN_NIST_256_TOP] = {
83 {0xFFFFFFFFFFFFFFFFULL,0x00000000FFFFFFFFULL,
84 0x0000000000000000ULL,0xFFFFFFFF00000001ULL},
85 {0xFFFFFFFFFFFFFFFEULL,0x00000001FFFFFFFFULL,
86 0x0000000000000000ULL,0xFFFFFFFE00000002ULL},
87 {0xFFFFFFFFFFFFFFFDULL,0x00000002FFFFFFFFULL,
88 0x0000000000000000ULL,0xFFFFFFFD00000003ULL},
89 {0xFFFFFFFFFFFFFFFCULL,0x00000003FFFFFFFFULL,
90 0x0000000000000000ULL,0xFFFFFFFC00000004ULL},
91 {0xFFFFFFFFFFFFFFFBULL,0x00000004FFFFFFFFULL,
92 0x0000000000000000ULL,0xFFFFFFFB00000005ULL},
94 static const BN_ULONG _nist_p_384[][BN_NIST_384_TOP] = {
95 {0x00000000FFFFFFFFULL,0xFFFFFFFF00000000ULL,0xFFFFFFFFFFFFFFFEULL,
96 0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL},
97 {0x00000001FFFFFFFEULL,0xFFFFFFFE00000000ULL,0xFFFFFFFFFFFFFFFDULL,
98 0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL},
99 {0x00000002FFFFFFFDULL,0xFFFFFFFD00000000ULL,0xFFFFFFFFFFFFFFFCULL,
100 0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL},
101 {0x00000003FFFFFFFCULL,0xFFFFFFFC00000000ULL,0xFFFFFFFFFFFFFFFBULL,
102 0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL},
103 {0x00000004FFFFFFFBULL,0xFFFFFFFB00000000ULL,0xFFFFFFFFFFFFFFFAULL,
104 0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL},
106 static const BN_ULONG _nist_p_521[] =
107 {0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL,
108 0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL,
109 0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL,
110 0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL,
111 0x00000000000001FFULL};
113 static const BN_ULONG _nist_p_192[][BN_NIST_192_TOP] = {
114 {0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFE,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF},
115 {0xFFFFFFFE,0xFFFFFFFF,0xFFFFFFFD,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF},
116 {0xFFFFFFFD,0xFFFFFFFF,0xFFFFFFFC,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF}
118 static const BN_ULONG _nist_p_224[][BN_NIST_224_TOP] = {
119 {0x00000001,0x00000000,0x00000000,0xFFFFFFFF,
120 0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF},
121 {0x00000002,0x00000000,0x00000000,0xFFFFFFFE,
122 0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF}
124 static const BN_ULONG _nist_p_256[][BN_NIST_256_TOP] = {
125 {0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0x00000000,
126 0x00000000,0x00000000,0x00000001,0xFFFFFFFF},
127 {0xFFFFFFFE,0xFFFFFFFF,0xFFFFFFFF,0x00000001,
128 0x00000000,0x00000000,0x00000002,0xFFFFFFFE},
129 {0xFFFFFFFD,0xFFFFFFFF,0xFFFFFFFF,0x00000002,
130 0x00000000,0x00000000,0x00000003,0xFFFFFFFD},
131 {0xFFFFFFFC,0xFFFFFFFF,0xFFFFFFFF,0x00000003,
132 0x00000000,0x00000000,0x00000004,0xFFFFFFFC},
133 {0xFFFFFFFB,0xFFFFFFFF,0xFFFFFFFF,0x00000004,
134 0x00000000,0x00000000,0x00000005,0xFFFFFFFB},
136 static const BN_ULONG _nist_p_384[][BN_NIST_384_TOP] = {
137 {0xFFFFFFFF,0x00000000,0x00000000,0xFFFFFFFF,0xFFFFFFFE,0xFFFFFFFF,
138 0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF},
139 {0xFFFFFFFE,0x00000001,0x00000000,0xFFFFFFFE,0xFFFFFFFD,0xFFFFFFFF,
140 0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF},
141 {0xFFFFFFFD,0x00000002,0x00000000,0xFFFFFFFD,0xFFFFFFFC,0xFFFFFFFF,
142 0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF},
143 {0xFFFFFFFC,0x00000003,0x00000000,0xFFFFFFFC,0xFFFFFFFB,0xFFFFFFFF,
144 0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF},
145 {0xFFFFFFFB,0x00000004,0x00000000,0xFFFFFFFB,0xFFFFFFFA,0xFFFFFFFF,
146 0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF},
148 static const BN_ULONG _nist_p_521[] = {0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,
149 0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,
150 0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,
151 0xFFFFFFFF,0x000001FF};
153 #error "unsupported BN_BITS2"
157 static const BIGNUM _bignum_nist_p_192 =
159 (BN_ULONG *)_nist_p_192[0],
166 static const BIGNUM _bignum_nist_p_224 =
168 (BN_ULONG *)_nist_p_224[0],
175 static const BIGNUM _bignum_nist_p_256 =
177 (BN_ULONG *)_nist_p_256[0],
184 static const BIGNUM _bignum_nist_p_384 =
186 (BN_ULONG *)_nist_p_384[0],
193 static const BIGNUM _bignum_nist_p_521 =
195 (BN_ULONG *)_nist_p_521,
203 const BIGNUM *BN_get0_nist_prime_192(void)
205 return &_bignum_nist_p_192;
208 const BIGNUM *BN_get0_nist_prime_224(void)
210 return &_bignum_nist_p_224;
213 const BIGNUM *BN_get0_nist_prime_256(void)
215 return &_bignum_nist_p_256;
218 const BIGNUM *BN_get0_nist_prime_384(void)
220 return &_bignum_nist_p_384;
223 const BIGNUM *BN_get0_nist_prime_521(void)
225 return &_bignum_nist_p_521;
229 static void nist_cp_bn_0(BN_ULONG *buf, BN_ULONG *a, int top, int max)
232 BN_ULONG *_tmp1 = (buf), *_tmp2 = (a);
234 OPENSSL_assert(top <= max);
235 for (i = (top); i != 0; i--)
237 for (i = (max) - (top); i != 0; i--)
238 *_tmp1++ = (BN_ULONG) 0;
241 static void nist_cp_bn(BN_ULONG *buf, BN_ULONG *a, int top)
244 BN_ULONG *_tmp1 = (buf), *_tmp2 = (a);
245 for (i = (top); i != 0; i--)
250 #define bn_cp_64(to, n, from, m) (to)[n] = (m>=0)?((from)[m]):0;
251 #define bn_64_set_0(to, n) (to)[n] = (BN_ULONG)0;
253 * two following macros are implemented under assumption that they
254 * are called in a sequence with *ascending* n, i.e. as they are...
256 #define bn_cp_32_naked(to, n, from, m) (((n)&1)?(to[(n)/2]|=((m)&1)?(from[(m)/2]&BN_MASK2h):(from[(m)/2]<<32))\
257 :(to[(n)/2] =((m)&1)?(from[(m)/2]>>32):(from[(m)/2]&BN_MASK2l)))
258 #define bn_32_set_0(to, n) (((n)&1)?(to[(n)/2]&=BN_MASK2l):(to[(n)/2]=0));
259 #define bn_cp_32(to,n,from,m) ((m)>=0)?bn_cp_32_naked(to,n,from,m):bn_32_set_0(to,n)
261 #define bn_cp_64(to, n, from, m) \
263 bn_cp_32(to, (n)*2, from, (m)*2); \
264 bn_cp_32(to, (n)*2+1, from, (m)*2+1); \
266 #define bn_64_set_0(to, n) \
268 bn_32_set_0(to, (n)*2); \
269 bn_32_set_0(to, (n)*2+1); \
272 #define bn_cp_32(to, n, from, m) (to)[n] = (m>=0)?((from)[m]):0;
273 #define bn_32_set_0(to, n) (to)[n] = (BN_ULONG)0;
275 #endif /* BN_BITS2 != 64 */
278 #define nist_set_192(to, from, a1, a2, a3) \
280 bn_cp_64(to, 0, from, (a3) - 3) \
281 bn_cp_64(to, 1, from, (a2) - 3) \
282 bn_cp_64(to, 2, from, (a1) - 3) \
285 int BN_nist_mod_192(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,
290 register BN_ULONG *r_d, *a_d = a->d;
291 BN_ULONG t_d[BN_NIST_192_TOP],
292 buf[BN_NIST_192_TOP],
293 c_d[BN_NIST_192_TOP],
297 field = &_bignum_nist_p_192; /* just to make sure */
299 if (BN_is_negative(a) || a->top > 2*BN_NIST_192_TOP)
300 return BN_nnmod(r, field, a, ctx);
302 i = BN_ucmp(field, a);
309 return (r == a) ? 1 : (BN_copy(r ,a) != NULL);
313 if (!bn_wexpand(r, BN_NIST_192_TOP))
316 nist_cp_bn(r_d, a_d, BN_NIST_192_TOP);
321 nist_cp_bn_0(buf, a_d + BN_NIST_192_TOP, top - BN_NIST_192_TOP, BN_NIST_192_TOP);
323 nist_set_192(t_d, buf, 0, 3, 3);
324 carry = bn_add_words(r_d, r_d, t_d, BN_NIST_192_TOP);
325 nist_set_192(t_d, buf, 4, 4, 0);
326 carry += bn_add_words(r_d, r_d, t_d, BN_NIST_192_TOP);
327 nist_set_192(t_d, buf, 5, 5, 5)
328 carry += bn_add_words(r_d, r_d, t_d, BN_NIST_192_TOP);
331 carry = bn_sub_words(r_d,r_d,_nist_p_192[carry-1],BN_NIST_192_TOP);
336 * we need 'if (carry==0 || result>=modulus) result-=modulus;'
337 * as comparison implies subtraction, we can write
338 * 'tmp=result-modulus; if (!carry || !borrow) result=tmp;'
339 * this is what happens below, but without explicit if:-) a.
341 mask = 0-(size_t)bn_sub_words(c_d,r_d,_nist_p_192[0],BN_NIST_192_TOP);
342 mask &= 0-(size_t)carry;
343 res = (BN_ULONG *)(((size_t)c_d&~mask) | ((size_t)r_d&mask));
344 nist_cp_bn(r_d, res, BN_NIST_192_TOP);
345 r->top = BN_NIST_192_TOP;
348 if (BN_ucmp(field, r) <= 0)
350 if (!BN_usub(r, r, field)) return 0;
356 typedef BN_ULONG (*bn_addsub_f)(BN_ULONG *,const BN_ULONG *,const BN_ULONG *,int);
358 #define nist_set_224(to, from, a1, a2, a3, a4, a5, a6, a7) \
360 bn_cp_32(to, 0, from, (a7) - 7) \
361 bn_cp_32(to, 1, from, (a6) - 7) \
362 bn_cp_32(to, 2, from, (a5) - 7) \
363 bn_cp_32(to, 3, from, (a4) - 7) \
364 bn_cp_32(to, 4, from, (a3) - 7) \
365 bn_cp_32(to, 5, from, (a2) - 7) \
366 bn_cp_32(to, 6, from, (a1) - 7) \
369 int BN_nist_mod_224(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,
374 BN_ULONG *r_d, *a_d = a->d;
375 BN_ULONG t_d[BN_NIST_224_TOP],
376 buf[BN_NIST_224_TOP],
377 c_d[BN_NIST_224_TOP],
380 union { bn_addsub_f f; size_t p; } u;
382 field = &_bignum_nist_p_224; /* just to make sure */
384 if (BN_is_negative(a) || a->top > 2*BN_NIST_224_TOP)
385 return BN_nnmod(r, field, a, ctx);
387 i = BN_ucmp(field, a);
394 return (r == a)? 1 : (BN_copy(r ,a) != NULL);
398 if (!bn_wexpand(r, BN_NIST_224_TOP))
401 nist_cp_bn(r_d, a_d, BN_NIST_224_TOP);
407 /* copy upper 256 bits of 448 bit number ... */
408 nist_cp_bn_0(t_d, a_d + (BN_NIST_224_TOP-1), top - (BN_NIST_224_TOP-1), BN_NIST_224_TOP);
409 /* ... and right shift by 32 to obtain upper 224 bits */
410 nist_set_224(buf, t_d, 14, 13, 12, 11, 10, 9, 8);
411 /* truncate lower part to 224 bits too */
412 r_d[BN_NIST_224_TOP-1] &= BN_MASK2l;
414 nist_cp_bn_0(buf, a_d + BN_NIST_224_TOP, top - BN_NIST_224_TOP, BN_NIST_224_TOP);
416 nist_set_224(t_d, buf, 10, 9, 8, 7, 0, 0, 0);
417 carry = bn_add_words(r_d, r_d, t_d, BN_NIST_224_TOP);
418 nist_set_224(t_d, buf, 0, 13, 12, 11, 0, 0, 0);
419 carry += bn_add_words(r_d, r_d, t_d, BN_NIST_224_TOP);
420 nist_set_224(t_d, buf, 13, 12, 11, 10, 9, 8, 7);
421 carry -= bn_sub_words(r_d, r_d, t_d, BN_NIST_224_TOP);
422 nist_set_224(t_d, buf, 0, 0, 0, 0, 13, 12, 11);
423 carry -= bn_sub_words(r_d, r_d, t_d, BN_NIST_224_TOP);
426 carry = (int)(r_d[BN_NIST_224_TOP-1]>>32);
431 carry = bn_sub_words(r_d,r_d,_nist_p_224[carry-1],BN_NIST_224_TOP);
433 carry=(int)(~(r_d[BN_NIST_224_TOP-1]>>32))&1;
438 /* it's a bit more comlicated logic in this case.
439 * if bn_add_words yields no carry, then result
440 * has to be adjusted by unconditionally *adding*
441 * the modulus. but if it does, then result has
442 * to be compared to the modulus and conditionally
443 * adjusted by *subtracting* the latter. */
444 carry = bn_add_words(r_d,r_d,_nist_p_224[-carry-1],BN_NIST_224_TOP);
445 mask = 0-(size_t)carry;
446 u.p = ((size_t)bn_sub_words&mask) | ((size_t)bn_add_words&~mask);
451 /* otherwise it's effectively same as in BN_nist_mod_192... */
452 mask = 0-(size_t)(*u.f)(c_d,r_d,_nist_p_224[0],BN_NIST_224_TOP);
453 mask &= 0-(size_t)carry;
454 res = (BN_ULONG *)(((size_t)c_d&~mask) | ((size_t)r_d&mask));
455 nist_cp_bn(r_d, res, BN_NIST_224_TOP);
456 r->top = BN_NIST_224_TOP;
459 if (BN_ucmp(field, r) <= 0)
461 if (!BN_usub(r, r, field)) return 0;
467 #define nist_set_256(to, from, a1, a2, a3, a4, a5, a6, a7, a8) \
469 bn_cp_32(to, 0, from, (a8) - 8) \
470 bn_cp_32(to, 1, from, (a7) - 8) \
471 bn_cp_32(to, 2, from, (a6) - 8) \
472 bn_cp_32(to, 3, from, (a5) - 8) \
473 bn_cp_32(to, 4, from, (a4) - 8) \
474 bn_cp_32(to, 5, from, (a3) - 8) \
475 bn_cp_32(to, 6, from, (a2) - 8) \
476 bn_cp_32(to, 7, from, (a1) - 8) \
479 int BN_nist_mod_256(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,
484 register BN_ULONG *a_d = a->d, *r_d;
485 BN_ULONG t_d[BN_NIST_256_TOP],
486 buf[BN_NIST_256_TOP],
487 c_d[BN_NIST_256_TOP],
490 union { bn_addsub_f f; size_t p; } u;
492 field = &_bignum_nist_p_256; /* just to make sure */
494 if (BN_is_negative(a) || a->top > 2*BN_NIST_256_TOP)
495 return BN_nnmod(r, field, a, ctx);
497 i = BN_ucmp(field, a);
504 return (r == a)? 1 : (BN_copy(r ,a) != NULL);
508 if (!bn_wexpand(r, BN_NIST_256_TOP))
511 nist_cp_bn(r_d, a_d, BN_NIST_256_TOP);
516 nist_cp_bn_0(buf, a_d + BN_NIST_256_TOP, top - BN_NIST_256_TOP, BN_NIST_256_TOP);
519 nist_set_256(t_d, buf, 15, 14, 13, 12, 11, 0, 0, 0);
521 nist_set_256(c_d, buf, 0, 15, 14, 13, 12, 0, 0, 0);
522 carry = bn_add_words(t_d, t_d, c_d, BN_NIST_256_TOP);
525 register BN_ULONG *ap,t,c;
528 for (i = BN_NIST_256_TOP; i != 0; --i)
531 *(ap++)=((t<<1)|c)&BN_MASK2;
537 carry += bn_add_words(r_d, r_d, t_d, BN_NIST_256_TOP);
539 nist_set_256(t_d, buf, 15, 14, 0, 0, 0, 10, 9, 8);
540 carry += bn_add_words(r_d, r_d, t_d, BN_NIST_256_TOP);
542 nist_set_256(t_d, buf, 8, 13, 15, 14, 13, 11, 10, 9);
543 carry += bn_add_words(r_d, r_d, t_d, BN_NIST_256_TOP);
545 nist_set_256(t_d, buf, 10, 8, 0, 0, 0, 13, 12, 11);
546 carry -= bn_sub_words(r_d, r_d, t_d, BN_NIST_256_TOP);
548 nist_set_256(t_d, buf, 11, 9, 0, 0, 15, 14, 13, 12);
549 carry -= bn_sub_words(r_d, r_d, t_d, BN_NIST_256_TOP);
551 nist_set_256(t_d, buf, 12, 0, 10, 9, 8, 15, 14, 13);
552 carry -= bn_sub_words(r_d, r_d, t_d, BN_NIST_256_TOP);
554 nist_set_256(t_d, buf, 13, 0, 11, 10, 9, 0, 15, 14);
555 carry -= bn_sub_words(r_d, r_d, t_d, BN_NIST_256_TOP);
557 /* see BN_nist_mod_224 for explanation */
560 carry = bn_sub_words(r_d,r_d,_nist_p_256[carry-1],BN_NIST_256_TOP);
563 carry = bn_add_words(r_d,r_d,_nist_p_256[-carry-1],BN_NIST_256_TOP);
564 mask = 0-(size_t)carry;
565 u.p = ((size_t)bn_sub_words&mask) | ((size_t)bn_add_words&~mask);
570 mask = 0-(size_t)(*u.f)(c_d,r_d,_nist_p_256[0],BN_NIST_256_TOP);
571 mask &= 0-(size_t)carry;
572 res = (BN_ULONG *)(((size_t)c_d&~mask) | ((size_t)r_d&mask));
573 nist_cp_bn(r_d, res, BN_NIST_256_TOP);
574 r->top = BN_NIST_256_TOP;
577 if (BN_ucmp(field, r) <= 0)
579 if (!BN_usub(r, r, field)) return 0;
585 #define nist_set_384(to,from,a1,a2,a3,a4,a5,a6,a7,a8,a9,a10,a11,a12) \
587 bn_cp_32(to, 0, from, (a12) - 12) \
588 bn_cp_32(to, 1, from, (a11) - 12) \
589 bn_cp_32(to, 2, from, (a10) - 12) \
590 bn_cp_32(to, 3, from, (a9) - 12) \
591 bn_cp_32(to, 4, from, (a8) - 12) \
592 bn_cp_32(to, 5, from, (a7) - 12) \
593 bn_cp_32(to, 6, from, (a6) - 12) \
594 bn_cp_32(to, 7, from, (a5) - 12) \
595 bn_cp_32(to, 8, from, (a4) - 12) \
596 bn_cp_32(to, 9, from, (a3) - 12) \
597 bn_cp_32(to, 10, from, (a2) - 12) \
598 bn_cp_32(to, 11, from, (a1) - 12) \
601 int BN_nist_mod_384(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,
606 register BN_ULONG *r_d, *a_d = a->d;
607 BN_ULONG t_d[BN_NIST_384_TOP],
608 buf[BN_NIST_384_TOP],
609 c_d[BN_NIST_384_TOP],
612 union { bn_addsub_f f; size_t p; } u;
614 field = &_bignum_nist_p_384; /* just to make sure */
616 if (BN_is_negative(a) || a->top > 2*BN_NIST_384_TOP)
617 return BN_nnmod(r, field, a, ctx);
619 i = BN_ucmp(field, a);
626 return (r == a)? 1 : (BN_copy(r ,a) != NULL);
630 if (!bn_wexpand(r, BN_NIST_384_TOP))
633 nist_cp_bn(r_d, a_d, BN_NIST_384_TOP);
638 nist_cp_bn_0(buf, a_d + BN_NIST_384_TOP, top - BN_NIST_384_TOP, BN_NIST_384_TOP);
641 nist_set_256(t_d, buf, 0, 0, 0, 0, 0, 23-4, 22-4, 21-4);
644 register BN_ULONG *ap,t,c;
647 for (i = 3; i != 0; --i)
650 *(ap++)=((t<<1)|c)&BN_MASK2;
655 carry = bn_add_words(r_d+(128/BN_BITS2), r_d+(128/BN_BITS2),
656 t_d, BN_NIST_256_TOP);
658 carry += bn_add_words(r_d, r_d, buf, BN_NIST_384_TOP);
660 nist_set_384(t_d,buf,20,19,18,17,16,15,14,13,12,23,22,21);
661 carry += bn_add_words(r_d, r_d, t_d, BN_NIST_384_TOP);
663 nist_set_384(t_d,buf,19,18,17,16,15,14,13,12,20,0,23,0);
664 carry += bn_add_words(r_d, r_d, t_d, BN_NIST_384_TOP);
666 nist_set_384(t_d, buf,0,0,0,0,23,22,21,20,0,0,0,0);
667 carry += bn_add_words(r_d, r_d, t_d, BN_NIST_384_TOP);
669 nist_set_384(t_d,buf,0,0,0,0,0,0,23,22,21,0,0,20);
670 carry += bn_add_words(r_d, r_d, t_d, BN_NIST_384_TOP);
672 nist_set_384(t_d,buf,22,21,20,19,18,17,16,15,14,13,12,23);
673 carry -= bn_sub_words(r_d, r_d, t_d, BN_NIST_384_TOP);
675 nist_set_384(t_d,buf,0,0,0,0,0,0,0,23,22,21,20,0);
676 carry -= bn_sub_words(r_d, r_d, t_d, BN_NIST_384_TOP);
678 nist_set_384(t_d,buf,0,0,0,0,0,0,0,23,23,0,0,0);
679 carry -= bn_sub_words(r_d, r_d, t_d, BN_NIST_384_TOP);
681 /* see BN_nist_mod_224 for explanation */
684 carry = bn_sub_words(r_d,r_d,_nist_p_384[carry-1],BN_NIST_384_TOP);
687 carry = bn_add_words(r_d,r_d,_nist_p_384[-carry-1],BN_NIST_384_TOP);
688 mask = 0-(size_t)carry;
689 u.p = ((size_t)bn_sub_words&mask) | ((size_t)bn_add_words&~mask);
694 mask = 0-(size_t)(*u.f)(c_d,r_d,_nist_p_384[0],BN_NIST_384_TOP);
695 mask &= 0-(size_t)carry;
696 res = (BN_ULONG *)(((size_t)c_d&~mask) | ((size_t)r_d&mask));
697 nist_cp_bn(r_d, res, BN_NIST_384_TOP);
698 r->top = BN_NIST_384_TOP;
701 if (BN_ucmp(field, r) <= 0)
703 if (!BN_usub(r, r, field)) return 0;
709 int BN_nist_mod_521(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,
713 #define BN_NIST_521_TOP_MASK (BN_ULONG)0x1FF
715 #define BN_NIST_521_TOP_MASK (BN_ULONG)0x1FF
721 field = &_bignum_nist_p_521; /* just to make sure */
723 if (BN_is_negative(a))
724 return BN_nnmod(r, field, a, ctx);
726 /* check whether a reduction is necessary */
728 if (top < BN_NIST_521_TOP || ( top == BN_NIST_521_TOP &&
729 (!(a->d[BN_NIST_521_TOP-1] & ~(BN_NIST_521_TOP_MASK)))))
731 int i = BN_ucmp(field, a);
740 OPENSSL_assert(i > 0); /* because 'field' is 1111...1111 */
742 return (r == a)? 1 : (BN_copy(r ,a) != NULL);
746 if (BN_num_bits(a) > 2*521)
747 return BN_nnmod(r, field, a, ctx);
750 tmp = BN_CTX_get(ctx);
754 if (!bn_wexpand(tmp, BN_NIST_521_TOP))
756 nist_cp_bn(tmp->d, a->d, BN_NIST_521_TOP);
758 tmp->top = BN_NIST_521_TOP;
759 tmp->d[BN_NIST_521_TOP-1] &= BN_NIST_521_TOP_MASK;
762 if (!BN_rshift(r, a, 521))
765 if (!BN_uadd(r, tmp, r))
768 if (BN_ucmp(field, r) <= 0)
770 if (!BN_usub(r, r, field)) goto err;