1/*
2 * ***** BEGIN LICENSE BLOCK *****
3 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
4 *
5 * The contents of this file are subject to the Mozilla Public License Version
6 * 1.1 (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 * http://www.mozilla.org/MPL/
9 *
10 * Software distributed under the License is distributed on an "AS IS" basis,
11 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
12 * for the specific language governing rights and limitations under the
13 * License.
14 *
15 * The Original Code is the elliptic curve math library for prime field curves.
16 *
17 * The Initial Developer of the Original Code is
18 * Sun Microsystems, Inc.
19 * Portions created by the Initial Developer are Copyright (C) 2003
20 * the Initial Developer. All Rights Reserved.
21 *
22 * Contributor(s):
23 *   Douglas Stebila <douglas@stebila.ca>
24 *
25 * Alternatively, the contents of this file may be used under the terms of
26 * either the GNU General Public License Version 2 or later (the "GPL"), or
27 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
28 * in which case the provisions of the GPL or the LGPL are applicable instead
29 * of those above. If you wish to allow use of your version of this file only
30 * under the terms of either the GPL or the LGPL, and not to allow others to
31 * use your version of this file under the terms of the MPL, indicate your
32 * decision by deleting the provisions above and replace them with the notice
33 * and other provisions required by the GPL or the LGPL. If you do not delete
34 * the provisions above, a recipient may use your version of this file under
35 * the terms of any one of the MPL, the GPL or the LGPL.
36 *
37 * ***** END LICENSE BLOCK ***** */
38/*
39 * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
40 * Use is subject to license terms.
41 *
42 * Sun elects to use this software under the MPL license.
43 */
44
45#pragma ident	"%Z%%M%	%I%	%E% SMI"
46
47#include "ecp.h"
48#include "mpi.h"
49#include "mplogic.h"
50#include "mpi-priv.h"
51#ifndef _KERNEL
52#include <stdlib.h>
53#endif
54
55/* Fast modular reduction for p384 = 2^384 - 2^128 - 2^96 + 2^32 - 1.  a can be r.
56 * Uses algorithm 2.30 from Hankerson, Menezes, Vanstone. Guide to
57 * Elliptic Curve Cryptography. */
58mp_err
59ec_GFp_nistp384_mod(const mp_int *a, mp_int *r, const GFMethod *meth)
60{
61	mp_err res = MP_OKAY;
62	int a_bits = mpl_significant_bits(a);
63	int i;
64
65	/* m1, m2 are statically-allocated mp_int of exactly the size we need */
66	mp_int m[10];
67
68#ifdef ECL_THIRTY_TWO_BIT
69	mp_digit s[10][12];
70	for (i = 0; i < 10; i++) {
71		MP_SIGN(&m[i]) = MP_ZPOS;
72		MP_ALLOC(&m[i]) = 12;
73		MP_USED(&m[i]) = 12;
74		MP_DIGITS(&m[i]) = s[i];
75	}
76#else
77	mp_digit s[10][6];
78	for (i = 0; i < 10; i++) {
79		MP_SIGN(&m[i]) = MP_ZPOS;
80		MP_ALLOC(&m[i]) = 6;
81		MP_USED(&m[i]) = 6;
82		MP_DIGITS(&m[i]) = s[i];
83	}
84#endif
85
86#ifdef ECL_THIRTY_TWO_BIT
87	/* for polynomials larger than twice the field size or polynomials
88	 * not using all words, use regular reduction */
89	if ((a_bits > 768) || (a_bits <= 736)) {
90		MP_CHECKOK(mp_mod(a, &meth->irr, r));
91	} else {
92		for (i = 0; i < 12; i++) {
93			s[0][i] = MP_DIGIT(a, i);
94		}
95		s[1][0] = 0;
96		s[1][1] = 0;
97		s[1][2] = 0;
98		s[1][3] = 0;
99		s[1][4] = MP_DIGIT(a, 21);
100		s[1][5] = MP_DIGIT(a, 22);
101		s[1][6] = MP_DIGIT(a, 23);
102		s[1][7] = 0;
103		s[1][8] = 0;
104		s[1][9] = 0;
105		s[1][10] = 0;
106		s[1][11] = 0;
107		for (i = 0; i < 12; i++) {
108			s[2][i] = MP_DIGIT(a, i+12);
109		}
110		s[3][0] = MP_DIGIT(a, 21);
111		s[3][1] = MP_DIGIT(a, 22);
112		s[3][2] = MP_DIGIT(a, 23);
113		for (i = 3; i < 12; i++) {
114			s[3][i] = MP_DIGIT(a, i+9);
115		}
116		s[4][0] = 0;
117		s[4][1] = MP_DIGIT(a, 23);
118		s[4][2] = 0;
119		s[4][3] = MP_DIGIT(a, 20);
120		for (i = 4; i < 12; i++) {
121			s[4][i] = MP_DIGIT(a, i+8);
122		}
123		s[5][0] = 0;
124		s[5][1] = 0;
125		s[5][2] = 0;
126		s[5][3] = 0;
127		s[5][4] = MP_DIGIT(a, 20);
128		s[5][5] = MP_DIGIT(a, 21);
129		s[5][6] = MP_DIGIT(a, 22);
130		s[5][7] = MP_DIGIT(a, 23);
131		s[5][8] = 0;
132		s[5][9] = 0;
133		s[5][10] = 0;
134		s[5][11] = 0;
135		s[6][0] = MP_DIGIT(a, 20);
136		s[6][1] = 0;
137		s[6][2] = 0;
138		s[6][3] = MP_DIGIT(a, 21);
139		s[6][4] = MP_DIGIT(a, 22);
140		s[6][5] = MP_DIGIT(a, 23);
141		s[6][6] = 0;
142		s[6][7] = 0;
143		s[6][8] = 0;
144		s[6][9] = 0;
145		s[6][10] = 0;
146		s[6][11] = 0;
147		s[7][0] = MP_DIGIT(a, 23);
148		for (i = 1; i < 12; i++) {
149			s[7][i] = MP_DIGIT(a, i+11);
150		}
151		s[8][0] = 0;
152		s[8][1] = MP_DIGIT(a, 20);
153		s[8][2] = MP_DIGIT(a, 21);
154		s[8][3] = MP_DIGIT(a, 22);
155		s[8][4] = MP_DIGIT(a, 23);
156		s[8][5] = 0;
157		s[8][6] = 0;
158		s[8][7] = 0;
159		s[8][8] = 0;
160		s[8][9] = 0;
161		s[8][10] = 0;
162		s[8][11] = 0;
163		s[9][0] = 0;
164		s[9][1] = 0;
165		s[9][2] = 0;
166		s[9][3] = MP_DIGIT(a, 23);
167		s[9][4] = MP_DIGIT(a, 23);
168		s[9][5] = 0;
169		s[9][6] = 0;
170		s[9][7] = 0;
171		s[9][8] = 0;
172		s[9][9] = 0;
173		s[9][10] = 0;
174		s[9][11] = 0;
175
176		MP_CHECKOK(mp_add(&m[0], &m[1], r));
177		MP_CHECKOK(mp_add(r, &m[1], r));
178		MP_CHECKOK(mp_add(r, &m[2], r));
179		MP_CHECKOK(mp_add(r, &m[3], r));
180		MP_CHECKOK(mp_add(r, &m[4], r));
181		MP_CHECKOK(mp_add(r, &m[5], r));
182		MP_CHECKOK(mp_add(r, &m[6], r));
183		MP_CHECKOK(mp_sub(r, &m[7], r));
184		MP_CHECKOK(mp_sub(r, &m[8], r));
185		MP_CHECKOK(mp_submod(r, &m[9], &meth->irr, r));
186		s_mp_clamp(r);
187	}
188#else
189	/* for polynomials larger than twice the field size or polynomials
190	 * not using all words, use regular reduction */
191	if ((a_bits > 768) || (a_bits <= 736)) {
192		MP_CHECKOK(mp_mod(a, &meth->irr, r));
193	} else {
194		for (i = 0; i < 6; i++) {
195			s[0][i] = MP_DIGIT(a, i);
196		}
197		s[1][0] = 0;
198		s[1][1] = 0;
199		s[1][2] = (MP_DIGIT(a, 10) >> 32) | (MP_DIGIT(a, 11) << 32);
200		s[1][3] = MP_DIGIT(a, 11) >> 32;
201		s[1][4] = 0;
202		s[1][5] = 0;
203		for (i = 0; i < 6; i++) {
204			s[2][i] = MP_DIGIT(a, i+6);
205		}
206		s[3][0] = (MP_DIGIT(a, 10) >> 32) | (MP_DIGIT(a, 11) << 32);
207		s[3][1] = (MP_DIGIT(a, 11) >> 32) | (MP_DIGIT(a, 6) << 32);
208		for (i = 2; i < 6; i++) {
209			s[3][i] = (MP_DIGIT(a, i+4) >> 32) | (MP_DIGIT(a, i+5) << 32);
210		}
211		s[4][0] = (MP_DIGIT(a, 11) >> 32) << 32;
212		s[4][1] = MP_DIGIT(a, 10) << 32;
213		for (i = 2; i < 6; i++) {
214			s[4][i] = MP_DIGIT(a, i+4);
215		}
216		s[5][0] = 0;
217		s[5][1] = 0;
218		s[5][2] = MP_DIGIT(a, 10);
219		s[5][3] = MP_DIGIT(a, 11);
220		s[5][4] = 0;
221		s[5][5] = 0;
222		s[6][0] = (MP_DIGIT(a, 10) << 32) >> 32;
223		s[6][1] = (MP_DIGIT(a, 10) >> 32) << 32;
224		s[6][2] = MP_DIGIT(a, 11);
225		s[6][3] = 0;
226		s[6][4] = 0;
227		s[6][5] = 0;
228		s[7][0] = (MP_DIGIT(a, 11) >> 32) | (MP_DIGIT(a, 6) << 32);
229		for (i = 1; i < 6; i++) {
230			s[7][i] = (MP_DIGIT(a, i+5) >> 32) | (MP_DIGIT(a, i+6) << 32);
231		}
232		s[8][0] = MP_DIGIT(a, 10) << 32;
233		s[8][1] = (MP_DIGIT(a, 10) >> 32) | (MP_DIGIT(a, 11) << 32);
234		s[8][2] = MP_DIGIT(a, 11) >> 32;
235		s[8][3] = 0;
236		s[8][4] = 0;
237		s[8][5] = 0;
238		s[9][0] = 0;
239		s[9][1] = (MP_DIGIT(a, 11) >> 32) << 32;
240		s[9][2] = MP_DIGIT(a, 11) >> 32;
241		s[9][3] = 0;
242		s[9][4] = 0;
243		s[9][5] = 0;
244
245		MP_CHECKOK(mp_add(&m[0], &m[1], r));
246		MP_CHECKOK(mp_add(r, &m[1], r));
247		MP_CHECKOK(mp_add(r, &m[2], r));
248		MP_CHECKOK(mp_add(r, &m[3], r));
249		MP_CHECKOK(mp_add(r, &m[4], r));
250		MP_CHECKOK(mp_add(r, &m[5], r));
251		MP_CHECKOK(mp_add(r, &m[6], r));
252		MP_CHECKOK(mp_sub(r, &m[7], r));
253		MP_CHECKOK(mp_sub(r, &m[8], r));
254		MP_CHECKOK(mp_submod(r, &m[9], &meth->irr, r));
255		s_mp_clamp(r);
256	}
257#endif
258
259  CLEANUP:
260	return res;
261}
262
263/* Compute the square of polynomial a, reduce modulo p384. Store the
264 * result in r.  r could be a.  Uses optimized modular reduction for p384.
265 */
266mp_err
267ec_GFp_nistp384_sqr(const mp_int *a, mp_int *r, const GFMethod *meth)
268{
269	mp_err res = MP_OKAY;
270
271	MP_CHECKOK(mp_sqr(a, r));
272	MP_CHECKOK(ec_GFp_nistp384_mod(r, r, meth));
273  CLEANUP:
274	return res;
275}
276
277/* Compute the product of two polynomials a and b, reduce modulo p384.
278 * Store the result in r.  r could be a or b; a could be b.  Uses
279 * optimized modular reduction for p384. */
280mp_err
281ec_GFp_nistp384_mul(const mp_int *a, const mp_int *b, mp_int *r,
282					const GFMethod *meth)
283{
284	mp_err res = MP_OKAY;
285
286	MP_CHECKOK(mp_mul(a, b, r));
287	MP_CHECKOK(ec_GFp_nistp384_mod(r, r, meth));
288  CLEANUP:
289	return res;
290}
291
292/* Wire in fast field arithmetic and precomputation of base point for
293 * named curves. */
294mp_err
295ec_group_set_gfp384(ECGroup *group, ECCurveName name)
296{
297	if (name == ECCurve_NIST_P384) {
298		group->meth->field_mod = &ec_GFp_nistp384_mod;
299		group->meth->field_mul = &ec_GFp_nistp384_mul;
300		group->meth->field_sqr = &ec_GFp_nistp384_sqr;
301	}
302	return MP_OKAY;
303}
304