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 binary polynomial 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 *   Sheueling Chang-Shantz <sheueling.chang@sun.com>,
24 *   Stephen Fung <fungstep@hotmail.com>, and
25 *   Douglas Stebila <douglas@stebila.ca>, Sun Microsystems Laboratories.
26 *
27 * Alternatively, the contents of this file may be used under the terms of
28 * either the GNU General Public License Version 2 or later (the "GPL"), or
29 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
30 * in which case the provisions of the GPL or the LGPL are applicable instead
31 * of those above. If you wish to allow use of your version of this file only
32 * under the terms of either the GPL or the LGPL, and not to allow others to
33 * use your version of this file under the terms of the MPL, indicate your
34 * decision by deleting the provisions above and replace them with the notice
35 * and other provisions required by the GPL or the LGPL. If you do not delete
36 * the provisions above, a recipient may use your version of this file under
37 * the terms of any one of the MPL, the GPL or the LGPL.
38 *
39 * ***** END LICENSE BLOCK ***** */
40/*
41 * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
42 * Use is subject to license terms.
43 *
44 * Sun elects to use this software under the MPL license.
45 */
46
47#include "ec2.h"
48#include "mp_gf2m.h"
49#include "mp_gf2m-priv.h"
50#include "mpi.h"
51#include "mpi-priv.h"
52#ifndef _KERNEL
53#include <stdlib.h>
54#endif
55
56/* Fast reduction for polynomials over a 163-bit curve. Assumes reduction
57 * polynomial with terms {163, 7, 6, 3, 0}. */
58mp_err
59ec_GF2m_163_mod(const mp_int *a, mp_int *r, const GFMethod *meth)
60{
61	mp_err res = MP_OKAY;
62	mp_digit *u, z;
63
64	if (a != r) {
65		MP_CHECKOK(mp_copy(a, r));
66	}
67#ifdef ECL_SIXTY_FOUR_BIT
68	if (MP_USED(r) < 6) {
69		MP_CHECKOK(s_mp_pad(r, 6));
70	}
71	u = MP_DIGITS(r);
72	MP_USED(r) = 6;
73
74	/* u[5] only has 6 significant bits */
75	z = u[5];
76	u[2] ^= (z << 36) ^ (z << 35) ^ (z << 32) ^ (z << 29);
77	z = u[4];
78	u[2] ^= (z >> 28) ^ (z >> 29) ^ (z >> 32) ^ (z >> 35);
79	u[1] ^= (z << 36) ^ (z << 35) ^ (z << 32) ^ (z << 29);
80	z = u[3];
81	u[1] ^= (z >> 28) ^ (z >> 29) ^ (z >> 32) ^ (z >> 35);
82	u[0] ^= (z << 36) ^ (z << 35) ^ (z << 32) ^ (z << 29);
83	z = u[2] >> 35;				/* z only has 29 significant bits */
84	u[0] ^= (z << 7) ^ (z << 6) ^ (z << 3) ^ z;
85	/* clear bits above 163 */
86	u[5] = u[4] = u[3] = 0;
87	u[2] ^= z << 35;
88#else
89	if (MP_USED(r) < 11) {
90		MP_CHECKOK(s_mp_pad(r, 11));
91	}
92	u = MP_DIGITS(r);
93	MP_USED(r) = 11;
94
95	/* u[11] only has 6 significant bits */
96	z = u[10];
97	u[5] ^= (z << 4) ^ (z << 3) ^ z ^ (z >> 3);
98	u[4] ^= (z << 29);
99	z = u[9];
100	u[5] ^= (z >> 28) ^ (z >> 29);
101	u[4] ^= (z << 4) ^ (z << 3) ^ z ^ (z >> 3);
102	u[3] ^= (z << 29);
103	z = u[8];
104	u[4] ^= (z >> 28) ^ (z >> 29);
105	u[3] ^= (z << 4) ^ (z << 3) ^ z ^ (z >> 3);
106	u[2] ^= (z << 29);
107	z = u[7];
108	u[3] ^= (z >> 28) ^ (z >> 29);
109	u[2] ^= (z << 4) ^ (z << 3) ^ z ^ (z >> 3);
110	u[1] ^= (z << 29);
111	z = u[6];
112	u[2] ^= (z >> 28) ^ (z >> 29);
113	u[1] ^= (z << 4) ^ (z << 3) ^ z ^ (z >> 3);
114	u[0] ^= (z << 29);
115	z = u[5] >> 3;				/* z only has 29 significant bits */
116	u[1] ^= (z >> 25) ^ (z >> 26);
117	u[0] ^= (z << 7) ^ (z << 6) ^ (z << 3) ^ z;
118	/* clear bits above 163 */
119	u[11] = u[10] = u[9] = u[8] = u[7] = u[6] = 0;
120	u[5] ^= z << 3;
121#endif
122	s_mp_clamp(r);
123
124  CLEANUP:
125	return res;
126}
127
128/* Fast squaring for polynomials over a 163-bit curve. Assumes reduction
129 * polynomial with terms {163, 7, 6, 3, 0}. */
130mp_err
131ec_GF2m_163_sqr(const mp_int *a, mp_int *r, const GFMethod *meth)
132{
133	mp_err res = MP_OKAY;
134	mp_digit *u, *v;
135
136	v = MP_DIGITS(a);
137
138#ifdef ECL_SIXTY_FOUR_BIT
139	if (MP_USED(a) < 3) {
140		return mp_bsqrmod(a, meth->irr_arr, r);
141	}
142	if (MP_USED(r) < 6) {
143		MP_CHECKOK(s_mp_pad(r, 6));
144	}
145	MP_USED(r) = 6;
146#else
147	if (MP_USED(a) < 6) {
148		return mp_bsqrmod(a, meth->irr_arr, r);
149	}
150	if (MP_USED(r) < 12) {
151		MP_CHECKOK(s_mp_pad(r, 12));
152	}
153	MP_USED(r) = 12;
154#endif
155	u = MP_DIGITS(r);
156
157#ifdef ECL_THIRTY_TWO_BIT
158	u[11] = gf2m_SQR1(v[5]);
159	u[10] = gf2m_SQR0(v[5]);
160	u[9] = gf2m_SQR1(v[4]);
161	u[8] = gf2m_SQR0(v[4]);
162	u[7] = gf2m_SQR1(v[3]);
163	u[6] = gf2m_SQR0(v[3]);
164#endif
165	u[5] = gf2m_SQR1(v[2]);
166	u[4] = gf2m_SQR0(v[2]);
167	u[3] = gf2m_SQR1(v[1]);
168	u[2] = gf2m_SQR0(v[1]);
169	u[1] = gf2m_SQR1(v[0]);
170	u[0] = gf2m_SQR0(v[0]);
171	return ec_GF2m_163_mod(r, r, meth);
172
173  CLEANUP:
174	return res;
175}
176
177/* Fast multiplication for polynomials over a 163-bit curve. Assumes
178 * reduction polynomial with terms {163, 7, 6, 3, 0}. */
179mp_err
180ec_GF2m_163_mul(const mp_int *a, const mp_int *b, mp_int *r,
181				const GFMethod *meth)
182{
183	mp_err res = MP_OKAY;
184	mp_digit a2 = 0, a1 = 0, a0, b2 = 0, b1 = 0, b0;
185
186#ifdef ECL_THIRTY_TWO_BIT
187	mp_digit a5 = 0, a4 = 0, a3 = 0, b5 = 0, b4 = 0, b3 = 0;
188	mp_digit rm[6];
189#endif
190
191	if (a == b) {
192		return ec_GF2m_163_sqr(a, r, meth);
193	} else {
194		switch (MP_USED(a)) {
195#ifdef ECL_THIRTY_TWO_BIT
196		case 6:
197			a5 = MP_DIGIT(a, 5);
198			/* FALLTHROUGH */
199		case 5:
200			a4 = MP_DIGIT(a, 4);
201			/* FALLTHROUGH */
202		case 4:
203			a3 = MP_DIGIT(a, 3);
204#endif
205			/* FALLTHROUGH */
206		case 3:
207			a2 = MP_DIGIT(a, 2);
208			/* FALLTHROUGH */
209		case 2:
210			a1 = MP_DIGIT(a, 1);
211			/* FALLTHROUGH */
212		default:
213			a0 = MP_DIGIT(a, 0);
214		}
215		switch (MP_USED(b)) {
216#ifdef ECL_THIRTY_TWO_BIT
217		case 6:
218			b5 = MP_DIGIT(b, 5);
219			/* FALLTHROUGH */
220		case 5:
221			b4 = MP_DIGIT(b, 4);
222			/* FALLTHROUGH */
223		case 4:
224			b3 = MP_DIGIT(b, 3);
225#endif
226			/* FALLTHROUGH */
227		case 3:
228			b2 = MP_DIGIT(b, 2);
229			/* FALLTHROUGH */
230		case 2:
231			b1 = MP_DIGIT(b, 1);
232			/* FALLTHROUGH */
233		default:
234			b0 = MP_DIGIT(b, 0);
235		}
236#ifdef ECL_SIXTY_FOUR_BIT
237		MP_CHECKOK(s_mp_pad(r, 6));
238		s_bmul_3x3(MP_DIGITS(r), a2, a1, a0, b2, b1, b0);
239		MP_USED(r) = 6;
240		s_mp_clamp(r);
241#else
242		MP_CHECKOK(s_mp_pad(r, 12));
243		s_bmul_3x3(MP_DIGITS(r) + 6, a5, a4, a3, b5, b4, b3);
244		s_bmul_3x3(MP_DIGITS(r), a2, a1, a0, b2, b1, b0);
245		s_bmul_3x3(rm, a5 ^ a2, a4 ^ a1, a3 ^ a0, b5 ^ b2, b4 ^ b1,
246				   b3 ^ b0);
247		rm[5] ^= MP_DIGIT(r, 5) ^ MP_DIGIT(r, 11);
248		rm[4] ^= MP_DIGIT(r, 4) ^ MP_DIGIT(r, 10);
249		rm[3] ^= MP_DIGIT(r, 3) ^ MP_DIGIT(r, 9);
250		rm[2] ^= MP_DIGIT(r, 2) ^ MP_DIGIT(r, 8);
251		rm[1] ^= MP_DIGIT(r, 1) ^ MP_DIGIT(r, 7);
252		rm[0] ^= MP_DIGIT(r, 0) ^ MP_DIGIT(r, 6);
253		MP_DIGIT(r, 8) ^= rm[5];
254		MP_DIGIT(r, 7) ^= rm[4];
255		MP_DIGIT(r, 6) ^= rm[3];
256		MP_DIGIT(r, 5) ^= rm[2];
257		MP_DIGIT(r, 4) ^= rm[1];
258		MP_DIGIT(r, 3) ^= rm[0];
259		MP_USED(r) = 12;
260		s_mp_clamp(r);
261#endif
262		return ec_GF2m_163_mod(r, r, meth);
263	}
264
265  CLEANUP:
266	return res;
267}
268
269/* Wire in fast field arithmetic for 163-bit curves. */
270mp_err
271ec_group_set_gf2m163(ECGroup *group, ECCurveName name)
272{
273	group->meth->field_mod = &ec_GF2m_163_mod;
274	group->meth->field_mul = &ec_GF2m_163_mul;
275	group->meth->field_sqr = &ec_GF2m_163_sqr;
276	return MP_OKAY;
277}
278