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comparison: security/nss/lib/freebl/ecl/ecp_384.c

security/nss/lib/freebl/ecl/ecp_384.c

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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 /* Fast modular reduction for p384 = 2^384 - 2^128 - 2^96 + 2^32 - 1. a can be r.
11 * Uses algorithm 2.30 from Hankerson, Menezes, Vanstone. Guide to
12 * Elliptic Curve Cryptography. */
13 static mp_err
14 ec_GFp_nistp384_mod(const mp_int *a, mp_int *r, const GFMethod *meth)
15 {
16 mp_err res = MP_OKAY;
17 int a_bits = mpl_significant_bits(a);
18 int i;
19
20 /* m1, m2 are statically-allocated mp_int of exactly the size we need */
21 mp_int m[10];
22
23 #ifdef ECL_THIRTY_TWO_BIT
24 mp_digit s[10][12];
25 for (i = 0; i < 10; i++) {
26 MP_SIGN(&m[i]) = MP_ZPOS;
27 MP_ALLOC(&m[i]) = 12;
28 MP_USED(&m[i]) = 12;
29 MP_DIGITS(&m[i]) = s[i];
30 }
31 #else
32 mp_digit s[10][6];
33 for (i = 0; i < 10; i++) {
34 MP_SIGN(&m[i]) = MP_ZPOS;
35 MP_ALLOC(&m[i]) = 6;
36 MP_USED(&m[i]) = 6;
37 MP_DIGITS(&m[i]) = s[i];
38 }
39 #endif
40
41 #ifdef ECL_THIRTY_TWO_BIT
42 /* for polynomials larger than twice the field size or polynomials
43 * not using all words, use regular reduction */
44 if ((a_bits > 768) || (a_bits <= 736)) {
45 MP_CHECKOK(mp_mod(a, &meth->irr, r));
46 } else {
47 for (i = 0; i < 12; i++) {
48 s[0][i] = MP_DIGIT(a, i);
49 }
50 s[1][0] = 0;
51 s[1][1] = 0;
52 s[1][2] = 0;
53 s[1][3] = 0;
54 s[1][4] = MP_DIGIT(a, 21);
55 s[1][5] = MP_DIGIT(a, 22);
56 s[1][6] = MP_DIGIT(a, 23);
57 s[1][7] = 0;
58 s[1][8] = 0;
59 s[1][9] = 0;
60 s[1][10] = 0;
61 s[1][11] = 0;
62 for (i = 0; i < 12; i++) {
63 s[2][i] = MP_DIGIT(a, i+12);
64 }
65 s[3][0] = MP_DIGIT(a, 21);
66 s[3][1] = MP_DIGIT(a, 22);
67 s[3][2] = MP_DIGIT(a, 23);
68 for (i = 3; i < 12; i++) {
69 s[3][i] = MP_DIGIT(a, i+9);
70 }
71 s[4][0] = 0;
72 s[4][1] = MP_DIGIT(a, 23);
73 s[4][2] = 0;
74 s[4][3] = MP_DIGIT(a, 20);
75 for (i = 4; i < 12; i++) {
76 s[4][i] = MP_DIGIT(a, i+8);
77 }
78 s[5][0] = 0;
79 s[5][1] = 0;
80 s[5][2] = 0;
81 s[5][3] = 0;
82 s[5][4] = MP_DIGIT(a, 20);
83 s[5][5] = MP_DIGIT(a, 21);
84 s[5][6] = MP_DIGIT(a, 22);
85 s[5][7] = MP_DIGIT(a, 23);
86 s[5][8] = 0;
87 s[5][9] = 0;
88 s[5][10] = 0;
89 s[5][11] = 0;
90 s[6][0] = MP_DIGIT(a, 20);
91 s[6][1] = 0;
92 s[6][2] = 0;
93 s[6][3] = MP_DIGIT(a, 21);
94 s[6][4] = MP_DIGIT(a, 22);
95 s[6][5] = MP_DIGIT(a, 23);
96 s[6][6] = 0;
97 s[6][7] = 0;
98 s[6][8] = 0;
99 s[6][9] = 0;
100 s[6][10] = 0;
101 s[6][11] = 0;
102 s[7][0] = MP_DIGIT(a, 23);
103 for (i = 1; i < 12; i++) {
104 s[7][i] = MP_DIGIT(a, i+11);
105 }
106 s[8][0] = 0;
107 s[8][1] = MP_DIGIT(a, 20);
108 s[8][2] = MP_DIGIT(a, 21);
109 s[8][3] = MP_DIGIT(a, 22);
110 s[8][4] = MP_DIGIT(a, 23);
111 s[8][5] = 0;
112 s[8][6] = 0;
113 s[8][7] = 0;
114 s[8][8] = 0;
115 s[8][9] = 0;
116 s[8][10] = 0;
117 s[8][11] = 0;
118 s[9][0] = 0;
119 s[9][1] = 0;
120 s[9][2] = 0;
121 s[9][3] = MP_DIGIT(a, 23);
122 s[9][4] = MP_DIGIT(a, 23);
123 s[9][5] = 0;
124 s[9][6] = 0;
125 s[9][7] = 0;
126 s[9][8] = 0;
127 s[9][9] = 0;
128 s[9][10] = 0;
129 s[9][11] = 0;
130
131 MP_CHECKOK(mp_add(&m[0], &m[1], r));
132 MP_CHECKOK(mp_add(r, &m[1], r));
133 MP_CHECKOK(mp_add(r, &m[2], r));
134 MP_CHECKOK(mp_add(r, &m[3], r));
135 MP_CHECKOK(mp_add(r, &m[4], r));
136 MP_CHECKOK(mp_add(r, &m[5], r));
137 MP_CHECKOK(mp_add(r, &m[6], r));
138 MP_CHECKOK(mp_sub(r, &m[7], r));
139 MP_CHECKOK(mp_sub(r, &m[8], r));
140 MP_CHECKOK(mp_submod(r, &m[9], &meth->irr, r));
141 s_mp_clamp(r);
142 }
143 #else
144 /* for polynomials larger than twice the field size or polynomials
145 * not using all words, use regular reduction */
146 if ((a_bits > 768) || (a_bits <= 736)) {
147 MP_CHECKOK(mp_mod(a, &meth->irr, r));
148 } else {
149 for (i = 0; i < 6; i++) {
150 s[0][i] = MP_DIGIT(a, i);
151 }
152 s[1][0] = 0;
153 s[1][1] = 0;
154 s[1][2] = (MP_DIGIT(a, 10) >> 32) | (MP_DIGIT(a, 11) << 32);
155 s[1][3] = MP_DIGIT(a, 11) >> 32;
156 s[1][4] = 0;
157 s[1][5] = 0;
158 for (i = 0; i < 6; i++) {
159 s[2][i] = MP_DIGIT(a, i+6);
160 }
161 s[3][0] = (MP_DIGIT(a, 10) >> 32) | (MP_DIGIT(a, 11) << 32);
162 s[3][1] = (MP_DIGIT(a, 11) >> 32) | (MP_DIGIT(a, 6) << 32);
163 for (i = 2; i < 6; i++) {
164 s[3][i] = (MP_DIGIT(a, i+4) >> 32) | (MP_DIGIT(a, i+5) << 32);
165 }
166 s[4][0] = (MP_DIGIT(a, 11) >> 32) << 32;
167 s[4][1] = MP_DIGIT(a, 10) << 32;
168 for (i = 2; i < 6; i++) {
169 s[4][i] = MP_DIGIT(a, i+4);
170 }
171 s[5][0] = 0;
172 s[5][1] = 0;
173 s[5][2] = MP_DIGIT(a, 10);
174 s[5][3] = MP_DIGIT(a, 11);
175 s[5][4] = 0;
176 s[5][5] = 0;
177 s[6][0] = (MP_DIGIT(a, 10) << 32) >> 32;
178 s[6][1] = (MP_DIGIT(a, 10) >> 32) << 32;
179 s[6][2] = MP_DIGIT(a, 11);
180 s[6][3] = 0;
181 s[6][4] = 0;
182 s[6][5] = 0;
183 s[7][0] = (MP_DIGIT(a, 11) >> 32) | (MP_DIGIT(a, 6) << 32);
184 for (i = 1; i < 6; i++) {
185 s[7][i] = (MP_DIGIT(a, i+5) >> 32) | (MP_DIGIT(a, i+6) << 32);
186 }
187 s[8][0] = MP_DIGIT(a, 10) << 32;
188 s[8][1] = (MP_DIGIT(a, 10) >> 32) | (MP_DIGIT(a, 11) << 32);
189 s[8][2] = MP_DIGIT(a, 11) >> 32;
190 s[8][3] = 0;
191 s[8][4] = 0;
192 s[8][5] = 0;
193 s[9][0] = 0;
194 s[9][1] = (MP_DIGIT(a, 11) >> 32) << 32;
195 s[9][2] = MP_DIGIT(a, 11) >> 32;
196 s[9][3] = 0;
197 s[9][4] = 0;
198 s[9][5] = 0;
199
200 MP_CHECKOK(mp_add(&m[0], &m[1], r));
201 MP_CHECKOK(mp_add(r, &m[1], r));
202 MP_CHECKOK(mp_add(r, &m[2], r));
203 MP_CHECKOK(mp_add(r, &m[3], r));
204 MP_CHECKOK(mp_add(r, &m[4], r));
205 MP_CHECKOK(mp_add(r, &m[5], r));
206 MP_CHECKOK(mp_add(r, &m[6], r));
207 MP_CHECKOK(mp_sub(r, &m[7], r));
208 MP_CHECKOK(mp_sub(r, &m[8], r));
209 MP_CHECKOK(mp_submod(r, &m[9], &meth->irr, r));
210 s_mp_clamp(r);
211 }
212 #endif
213
214 CLEANUP:
215 return res;
216 }
217
218 /* Compute the square of polynomial a, reduce modulo p384. Store the
219 * result in r. r could be a. Uses optimized modular reduction for p384.
220 */
221 static mp_err
222 ec_GFp_nistp384_sqr(const mp_int *a, mp_int *r, const GFMethod *meth)
223 {
224 mp_err res = MP_OKAY;
225
226 MP_CHECKOK(mp_sqr(a, r));
227 MP_CHECKOK(ec_GFp_nistp384_mod(r, r, meth));
228 CLEANUP:
229 return res;
230 }
231
232 /* Compute the product of two polynomials a and b, reduce modulo p384.
233 * Store the result in r. r could be a or b; a could be b. Uses
234 * optimized modular reduction for p384. */
235 static mp_err
236 ec_GFp_nistp384_mul(const mp_int *a, const mp_int *b, mp_int *r,
237 const GFMethod *meth)
238 {
239 mp_err res = MP_OKAY;
240
241 MP_CHECKOK(mp_mul(a, b, r));
242 MP_CHECKOK(ec_GFp_nistp384_mod(r, r, meth));
243 CLEANUP:
244 return res;
245 }
246
247 /* Wire in fast field arithmetic and precomputation of base point for
248 * named curves. */
249 mp_err
250 ec_group_set_gfp384(ECGroup *group, ECCurveName name)
251 {
252 if (name == ECCurve_NIST_P384) {
253 group->meth->field_mod = &ec_GFp_nistp384_mod;
254 group->meth->field_mul = &ec_GFp_nistp384_mul;
255 group->meth->field_sqr = &ec_GFp_nistp384_sqr;
256 }
257 return MP_OKAY;
258 }

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