Mercurial > trustbridge > nss-cmake-static
comparison nss/lib/freebl/ecl/ecp_521.c @ 0:1e5118fa0cb1
This is NSS with a Cmake Buildsyste
To compile a static NSS library for Windows we've used the
Chromium-NSS fork and added a Cmake buildsystem to compile
it statically for Windows. See README.chromium for chromium
changes and README.trustbridge for our modifications.
| author | Andre Heinecke <andre.heinecke@intevation.de> |
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| date | Mon, 28 Jul 2014 10:47:06 +0200 |
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| -1:000000000000 | 0:1e5118fa0cb1 |
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| 1 /* This Source Code Form is subject to the terms of the Mozilla Public | |
| 2 * License, v. 2.0. If a copy of the MPL was not distributed with this | |
| 3 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ | |
| 4 | |
| 5 #include "ecp.h" | |
| 6 #include "mpi.h" | |
| 7 #include "mplogic.h" | |
| 8 #include "mpi-priv.h" | |
| 9 | |
| 10 #define ECP521_DIGITS ECL_CURVE_DIGITS(521) | |
| 11 | |
| 12 /* Fast modular reduction for p521 = 2^521 - 1. a can be r. Uses | |
| 13 * algorithm 2.31 from Hankerson, Menezes, Vanstone. Guide to | |
| 14 * Elliptic Curve Cryptography. */ | |
| 15 static mp_err | |
| 16 ec_GFp_nistp521_mod(const mp_int *a, mp_int *r, const GFMethod *meth) | |
| 17 { | |
| 18 mp_err res = MP_OKAY; | |
| 19 int a_bits = mpl_significant_bits(a); | |
| 20 int i; | |
| 21 | |
| 22 /* m1, m2 are statically-allocated mp_int of exactly the size we need */ | |
| 23 mp_int m1; | |
| 24 | |
| 25 mp_digit s1[ECP521_DIGITS] = { 0 }; | |
| 26 | |
| 27 MP_SIGN(&m1) = MP_ZPOS; | |
| 28 MP_ALLOC(&m1) = ECP521_DIGITS; | |
| 29 MP_USED(&m1) = ECP521_DIGITS; | |
| 30 MP_DIGITS(&m1) = s1; | |
| 31 | |
| 32 if (a_bits < 521) { | |
| 33 if (a==r) return MP_OKAY; | |
| 34 return mp_copy(a, r); | |
| 35 } | |
| 36 /* for polynomials larger than twice the field size or polynomials | |
| 37 * not using all words, use regular reduction */ | |
| 38 if (a_bits > (521*2)) { | |
| 39 MP_CHECKOK(mp_mod(a, &meth->irr, r)); | |
| 40 } else { | |
| 41 #define FIRST_DIGIT (ECP521_DIGITS-1) | |
| 42 for (i = FIRST_DIGIT; i < MP_USED(a)-1; i++) { | |
| 43 s1[i-FIRST_DIGIT] = (MP_DIGIT(a, i) >> 9) | |
| 44 | (MP_DIGIT(a, 1+i) << (MP_DIGIT_BIT-9)); | |
| 45 } | |
| 46 s1[i-FIRST_DIGIT] = MP_DIGIT(a, i) >> 9; | |
| 47 | |
| 48 if ( a != r ) { | |
| 49 MP_CHECKOK(s_mp_pad(r,ECP521_DIGITS)); | |
| 50 for (i = 0; i < ECP521_DIGITS; i++) { | |
| 51 MP_DIGIT(r,i) = MP_DIGIT(a, i); | |
| 52 } | |
| 53 } | |
| 54 MP_USED(r) = ECP521_DIGITS; | |
| 55 MP_DIGIT(r,FIRST_DIGIT) &= 0x1FF; | |
| 56 | |
| 57 MP_CHECKOK(s_mp_add(r, &m1)); | |
| 58 if (MP_DIGIT(r, FIRST_DIGIT) & 0x200) { | |
| 59 MP_CHECKOK(s_mp_add_d(r,1)); | |
| 60 MP_DIGIT(r,FIRST_DIGIT) &= 0x1FF; | |
| 61 } else if (s_mp_cmp(r, &meth->irr) == 0) { | |
| 62 mp_zero(r); | |
| 63 } | |
| 64 s_mp_clamp(r); | |
| 65 } | |
| 66 | |
| 67 CLEANUP: | |
| 68 return res; | |
| 69 } | |
| 70 | |
| 71 /* Compute the square of polynomial a, reduce modulo p521. Store the | |
| 72 * result in r. r could be a. Uses optimized modular reduction for p521. | |
| 73 */ | |
| 74 static mp_err | |
| 75 ec_GFp_nistp521_sqr(const mp_int *a, mp_int *r, const GFMethod *meth) | |
| 76 { | |
| 77 mp_err res = MP_OKAY; | |
| 78 | |
| 79 MP_CHECKOK(mp_sqr(a, r)); | |
| 80 MP_CHECKOK(ec_GFp_nistp521_mod(r, r, meth)); | |
| 81 CLEANUP: | |
| 82 return res; | |
| 83 } | |
| 84 | |
| 85 /* Compute the product of two polynomials a and b, reduce modulo p521. | |
| 86 * Store the result in r. r could be a or b; a could be b. Uses | |
| 87 * optimized modular reduction for p521. */ | |
| 88 static mp_err | |
| 89 ec_GFp_nistp521_mul(const mp_int *a, const mp_int *b, mp_int *r, | |
| 90 const GFMethod *meth) | |
| 91 { | |
| 92 mp_err res = MP_OKAY; | |
| 93 | |
| 94 MP_CHECKOK(mp_mul(a, b, r)); | |
| 95 MP_CHECKOK(ec_GFp_nistp521_mod(r, r, meth)); | |
| 96 CLEANUP: | |
| 97 return res; | |
| 98 } | |
| 99 | |
| 100 /* Divides two field elements. If a is NULL, then returns the inverse of | |
| 101 * b. */ | |
| 102 static mp_err | |
| 103 ec_GFp_nistp521_div(const mp_int *a, const mp_int *b, mp_int *r, | |
| 104 const GFMethod *meth) | |
| 105 { | |
| 106 mp_err res = MP_OKAY; | |
| 107 mp_int t; | |
| 108 | |
| 109 /* If a is NULL, then return the inverse of b, otherwise return a/b. */ | |
| 110 if (a == NULL) { | |
| 111 return mp_invmod(b, &meth->irr, r); | |
| 112 } else { | |
| 113 /* MPI doesn't support divmod, so we implement it using invmod and | |
| 114 * mulmod. */ | |
| 115 MP_CHECKOK(mp_init(&t)); | |
| 116 MP_CHECKOK(mp_invmod(b, &meth->irr, &t)); | |
| 117 MP_CHECKOK(mp_mul(a, &t, r)); | |
| 118 MP_CHECKOK(ec_GFp_nistp521_mod(r, r, meth)); | |
| 119 CLEANUP: | |
| 120 mp_clear(&t); | |
| 121 return res; | |
| 122 } | |
| 123 } | |
| 124 | |
| 125 /* Wire in fast field arithmetic and precomputation of base point for | |
| 126 * named curves. */ | |
| 127 mp_err | |
| 128 ec_group_set_gfp521(ECGroup *group, ECCurveName name) | |
| 129 { | |
| 130 if (name == ECCurve_NIST_P521) { | |
| 131 group->meth->field_mod = &ec_GFp_nistp521_mod; | |
| 132 group->meth->field_mul = &ec_GFp_nistp521_mul; | |
| 133 group->meth->field_sqr = &ec_GFp_nistp521_sqr; | |
| 134 group->meth->field_div = &ec_GFp_nistp521_div; | |
| 135 } | |
| 136 return MP_OKAY; | |
| 137 } |