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Diffstat (limited to 'src/lib/libcrypto/bn/bn_exp2.c')
-rw-r--r--src/lib/libcrypto/bn/bn_exp2.c357
1 files changed, 229 insertions, 128 deletions
diff --git a/src/lib/libcrypto/bn/bn_exp2.c b/src/lib/libcrypto/bn/bn_exp2.c
index 4f4e9e3299..29029f4c72 100644
--- a/src/lib/libcrypto/bn/bn_exp2.c
+++ b/src/lib/libcrypto/bn/bn_exp2.c
@@ -1,27 +1,128 @@
1/* crypto/bn/bn_exp2.c */
2/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
3 * All rights reserved.
4 *
5 * This package is an SSL implementation written
6 * by Eric Young (eay@cryptsoft.com).
7 * The implementation was written so as to conform with Netscapes SSL.
8 *
9 * This library is free for commercial and non-commercial use as long as
10 * the following conditions are aheared to. The following conditions
11 * apply to all code found in this distribution, be it the RC4, RSA,
12 * lhash, DES, etc., code; not just the SSL code. The SSL documentation
13 * included with this distribution is covered by the same copyright terms
14 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
15 *
16 * Copyright remains Eric Young's, and as such any Copyright notices in
17 * the code are not to be removed.
18 * If this package is used in a product, Eric Young should be given attribution
19 * as the author of the parts of the library used.
20 * This can be in the form of a textual message at program startup or
21 * in documentation (online or textual) provided with the package.
22 *
23 * Redistribution and use in source and binary forms, with or without
24 * modification, are permitted provided that the following conditions
25 * are met:
26 * 1. Redistributions of source code must retain the copyright
27 * notice, this list of conditions and the following disclaimer.
28 * 2. Redistributions in binary form must reproduce the above copyright
29 * notice, this list of conditions and the following disclaimer in the
30 * documentation and/or other materials provided with the distribution.
31 * 3. All advertising materials mentioning features or use of this software
32 * must display the following acknowledgement:
33 * "This product includes cryptographic software written by
34 * Eric Young (eay@cryptsoft.com)"
35 * The word 'cryptographic' can be left out if the rouines from the library
36 * being used are not cryptographic related :-).
37 * 4. If you include any Windows specific code (or a derivative thereof) from
38 * the apps directory (application code) you must include an acknowledgement:
39 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
40 *
41 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
42 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
43 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
44 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
45 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
46 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
47 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
49 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
50 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
51 * SUCH DAMAGE.
52 *
53 * The licence and distribution terms for any publically available version or
54 * derivative of this code cannot be changed. i.e. this code cannot simply be
55 * copied and put under another distribution licence
56 * [including the GNU Public Licence.]
57 */
58/* ====================================================================
59 * Copyright (c) 1998-2000 The OpenSSL Project. All rights reserved.
60 *
61 * Redistribution and use in source and binary forms, with or without
62 * modification, are permitted provided that the following conditions
63 * are met:
64 *
65 * 1. Redistributions of source code must retain the above copyright
66 * notice, this list of conditions and the following disclaimer.
67 *
68 * 2. Redistributions in binary form must reproduce the above copyright
69 * notice, this list of conditions and the following disclaimer in
70 * the documentation and/or other materials provided with the
71 * distribution.
72 *
73 * 3. All advertising materials mentioning features or use of this
74 * software must display the following acknowledgment:
75 * "This product includes software developed by the OpenSSL Project
76 * for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
77 *
78 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
79 * endorse or promote products derived from this software without
80 * prior written permission. For written permission, please contact
81 * openssl-core@openssl.org.
82 *
83 * 5. Products derived from this software may not be called "OpenSSL"
84 * nor may "OpenSSL" appear in their names without prior written
85 * permission of the OpenSSL Project.
86 *
87 * 6. Redistributions of any form whatsoever must retain the following
88 * acknowledgment:
89 * "This product includes software developed by the OpenSSL Project
90 * for use in the OpenSSL Toolkit (http://www.openssl.org/)"
91 *
92 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
93 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
94 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
95 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
96 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
97 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
98 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
99 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
100 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
101 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
102 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
103 * OF THE POSSIBILITY OF SUCH DAMAGE.
104 * ====================================================================
105 *
106 * This product includes cryptographic software written by Eric Young
107 * (eay@cryptsoft.com). This product includes software written by Tim
108 * Hudson (tjh@cryptsoft.com).
109 *
110 */
111
1#include <stdio.h> 112#include <stdio.h>
2#include "cryptlib.h" 113#include "cryptlib.h"
3#include "bn_lcl.h" 114#include "bn_lcl.h"
4 115
5/* I've done some timing with different table sizes. 116#define TABLE_SIZE 32
6 * The main hassle is that even with bits set at 3, this requires
7 * 63 BIGNUMs to store the pre-calculated values.
8 * 512 1024
9 * bits=1 75.4% 79.4%
10 * bits=2 61.2% 62.4%
11 * bits=3 61.3% 59.3%
12 * The lack of speed improvement is also a function of the pre-calculation
13 * which could be removed.
14 */
15#define EXP2_TABLE_BITS 2 /* 1 2 3 4 5 */
16#define EXP2_TABLE_SIZE 4 /* 2 4 8 16 32 */
17 117
18int BN_mod_exp2_mont(BIGNUM *rr, BIGNUM *a1, BIGNUM *p1, BIGNUM *a2, 118int BN_mod_exp2_mont(BIGNUM *rr, BIGNUM *a1, BIGNUM *p1, BIGNUM *a2,
19 BIGNUM *p2, BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *in_mont) 119 BIGNUM *p2, BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *in_mont)
20 { 120 {
21 int i,j,k,bits,bits1,bits2,ret=0,wstart,wend,window,xvalue,yvalue; 121 int i,j,bits,b,bits1,bits2,ret=0,wpos1,wpos2,window1,window2,wvalue1,wvalue2;
22 int start=1,ts=0,x,y; 122 int r_is_one=1,ts1=0,ts2=0;
23 BIGNUM *d,*aa1,*aa2,*r; 123 BIGNUM *d,*r;
24 BIGNUM val[EXP2_TABLE_SIZE][EXP2_TABLE_SIZE]; 124 BIGNUM *a_mod_m;
125 BIGNUM val1[TABLE_SIZE], val2[TABLE_SIZE];
25 BN_MONT_CTX *mont=NULL; 126 BN_MONT_CTX *mont=NULL;
26 127
27 bn_check_top(a1); 128 bn_check_top(a1);
@@ -32,7 +133,7 @@ int BN_mod_exp2_mont(BIGNUM *rr, BIGNUM *a1, BIGNUM *p1, BIGNUM *a2,
32 133
33 if (!(m->d[0] & 1)) 134 if (!(m->d[0] & 1))
34 { 135 {
35 BNerr(BN_F_BN_MOD_EXP_MONT,BN_R_CALLED_WITH_EVEN_MODULUS); 136 BNerr(BN_F_BN_MOD_EXP2_MONT,BN_R_CALLED_WITH_EVEN_MODULUS);
36 return(0); 137 return(0);
37 } 138 }
38 bits1=BN_num_bits(p1); 139 bits1=BN_num_bits(p1);
@@ -42,17 +143,13 @@ int BN_mod_exp2_mont(BIGNUM *rr, BIGNUM *a1, BIGNUM *p1, BIGNUM *a2,
42 BN_one(rr); 143 BN_one(rr);
43 return(1); 144 return(1);
44 } 145 }
146 bits=(bits1 > bits2)?bits1:bits2;
45 147
46 BN_CTX_start(ctx); 148 BN_CTX_start(ctx);
47 d = BN_CTX_get(ctx); 149 d = BN_CTX_get(ctx);
48 r = BN_CTX_get(ctx); 150 r = BN_CTX_get(ctx);
49 if (d == NULL || r == NULL) goto err; 151 if (d == NULL || r == NULL) goto err;
50 152
51 bits=(bits1 > bits2)?bits1:bits2;
52
53 /* If this is not done, things will break in the montgomery
54 * part */
55
56 if (in_mont != NULL) 153 if (in_mont != NULL)
57 mont=in_mont; 154 mont=in_mont;
58 else 155 else
@@ -61,139 +158,143 @@ int BN_mod_exp2_mont(BIGNUM *rr, BIGNUM *a1, BIGNUM *p1, BIGNUM *a2,
61 if (!BN_MONT_CTX_set(mont,m,ctx)) goto err; 158 if (!BN_MONT_CTX_set(mont,m,ctx)) goto err;
62 } 159 }
63 160
64 BN_init(&(val[0][0])); 161 window1 = BN_window_bits_for_exponent_size(bits1);
65 BN_init(&(val[1][1])); 162 window2 = BN_window_bits_for_exponent_size(bits2);
66 BN_init(&(val[0][1])); 163
67 BN_init(&(val[1][0])); 164 /*
68 ts=1; 165 * Build table for a1: val1[i] := a1^(2*i + 1) mod m for i = 0 .. 2^(window1-1)
166 */
167 BN_init(&val1[0]);
168 ts1=1;
69 if (BN_ucmp(a1,m) >= 0) 169 if (BN_ucmp(a1,m) >= 0)
70 { 170 {
71 BN_mod(&(val[1][0]),a1,m,ctx); 171 if (!BN_mod(&(val1[0]),a1,m,ctx))
72 aa1= &(val[1][0]); 172 goto err;
173 a_mod_m = &(val1[0]);
73 } 174 }
74 else 175 else
75 aa1=a1; 176 a_mod_m = a1;
177 if (!BN_to_montgomery(&(val1[0]),a_mod_m,mont,ctx)) goto err;
178 if (window1 > 1)
179 {
180 if (!BN_mod_mul_montgomery(d,&(val1[0]),&(val1[0]),mont,ctx)) goto err;
181
182 j=1<<(window1-1);
183 for (i=1; i<j; i++)
184 {
185 BN_init(&(val1[i]));
186 if (!BN_mod_mul_montgomery(&(val1[i]),&(val1[i-1]),d,mont,ctx))
187 goto err;
188 }
189 ts1=i;
190 }
191
192
193 /*
194 * Build table for a2: val2[i] := a2^(2*i + 1) mod m for i = 0 .. 2^(window2-1)
195 */
196 BN_init(&val2[0]);
197 ts2=1;
76 if (BN_ucmp(a2,m) >= 0) 198 if (BN_ucmp(a2,m) >= 0)
77 { 199 {
78 BN_mod(&(val[0][1]),a2,m,ctx); 200 if (!BN_mod(&(val2[0]),a2,m,ctx))
79 aa2= &(val[0][1]); 201 goto err;
202 a_mod_m = &(val2[0]);
80 } 203 }
81 else 204 else
82 aa2=a2; 205 a_mod_m = a2;
83 if (!BN_to_montgomery(&(val[1][0]),aa1,mont,ctx)) goto err; 206 if (!BN_to_montgomery(&(val2[0]),a_mod_m,mont,ctx)) goto err;
84 if (!BN_to_montgomery(&(val[0][1]),aa2,mont,ctx)) goto err; 207 if (window2 > 1)
85 if (!BN_mod_mul_montgomery(&(val[1][1]),
86 &(val[1][0]),&(val[0][1]),mont,ctx))
87 goto err;
88
89#if 0
90 if (bits <= 20) /* This is probably 3 or 0x10001, so just do singles */
91 window=1;
92 else if (bits > 250)
93 window=5; /* max size of window */
94 else if (bits >= 120)
95 window=4;
96 else
97 window=3;
98#else
99 window=EXP2_TABLE_BITS;
100#endif
101
102 k=1<<window;
103 for (x=0; x<k; x++)
104 { 208 {
105 if (x >= 2) 209 if (!BN_mod_mul_montgomery(d,&(val2[0]),&(val2[0]),mont,ctx)) goto err;
106 { 210
107 BN_init(&(val[x][0])); 211 j=1<<(window2-1);
108 BN_init(&(val[x][1])); 212 for (i=1; i<j; i++)
109 if (!BN_mod_mul_montgomery(&(val[x][0]),
110 &(val[1][0]),&(val[x-1][0]),mont,ctx)) goto err;
111 if (!BN_mod_mul_montgomery(&(val[x][1]),
112 &(val[1][0]),&(val[x-1][1]),mont,ctx)) goto err;
113 }
114 for (y=2; y<k; y++)
115 { 213 {
116 BN_init(&(val[x][y])); 214 BN_init(&(val2[i]));
117 if (!BN_mod_mul_montgomery(&(val[x][y]), 215 if (!BN_mod_mul_montgomery(&(val2[i]),&(val2[i-1]),d,mont,ctx))
118 &(val[x][y-1]),&(val[0][1]),mont,ctx))
119 goto err; 216 goto err;
120 } 217 }
218 ts2=i;
121 } 219 }
122 ts=k; 220
123 221
124 start=1; /* This is used to avoid multiplication etc 222 /* Now compute the power product, using independent windows. */
125 * when there is only the value '1' in the 223 r_is_one=1;
126 * buffer. */ 224 wvalue1=0; /* The 'value' of the first window */
127 xvalue=0; /* The 'x value' of the window */ 225 wvalue2=0; /* The 'value' of the second window */
128 yvalue=0; /* The 'y value' of the window */ 226 wpos1=0; /* If wvalue1 > 0, the bottom bit of the first window */
129 wstart=bits-1; /* The top bit of the window */ 227 wpos2=0; /* If wvalue2 > 0, the bottom bit of the second window */
130 wend=0; /* The bottom bit of the window */ 228
131 229 if (!BN_to_montgomery(r,BN_value_one(),mont,ctx)) goto err;
132 if (!BN_to_montgomery(r,BN_value_one(),mont,ctx)) goto err; 230 for (b=bits-1; b>=0; b--)
133 for (;;)
134 { 231 {
135 xvalue=BN_is_bit_set(p1,wstart); 232 if (!r_is_one)
136 yvalue=BN_is_bit_set(p2,wstart);
137 if (!(xvalue || yvalue))
138 { 233 {
139 if (!start) 234 if (!BN_mod_mul_montgomery(r,r,r,mont,ctx))
235 goto err;
236 }
237
238 if (!wvalue1)
239 if (BN_is_bit_set(p1, b))
140 { 240 {
141 if (!BN_mod_mul_montgomery(r,r,r,mont,ctx)) 241 /* consider bits b-window1+1 .. b for this window */
142 goto err; 242 i = b-window1+1;
243 while (!BN_is_bit_set(p1, i)) /* works for i<0 */
244 i++;
245 wpos1 = i;
246 wvalue1 = 1;
247 for (i = b-1; i >= wpos1; i--)
248 {
249 wvalue1 <<= 1;
250 if (BN_is_bit_set(p1, i))
251 wvalue1++;
252 }
143 } 253 }
144 wstart--; 254
145 if (wstart < 0) break; 255 if (!wvalue2)
146 continue; 256 if (BN_is_bit_set(p2, b))
147 }
148 /* We now have wstart on a 'set' bit, we now need to work out
149 * how bit a window to do. To do this we need to scan
150 * forward until the last set bit before the end of the
151 * window */
152 j=wstart;
153 /* xvalue=BN_is_bit_set(p1,wstart); already set */
154 /* yvalue=BN_is_bit_set(p1,wstart); already set */
155 wend=0;
156 for (i=1; i<window; i++)
157 {
158 if (wstart-i < 0) break;
159 xvalue+=xvalue;
160 xvalue|=BN_is_bit_set(p1,wstart-i);
161 yvalue+=yvalue;
162 yvalue|=BN_is_bit_set(p2,wstart-i);
163 }
164
165 /* i is the size of the current window */
166 /* add the 'bytes above' */
167 if (!start)
168 for (j=0; j<i; j++)
169 { 257 {
170 if (!BN_mod_mul_montgomery(r,r,r,mont,ctx)) 258 /* consider bits b-window2+1 .. b for this window */
171 goto err; 259 i = b-window2+1;
260 while (!BN_is_bit_set(p2, i))
261 i++;
262 wpos2 = i;
263 wvalue2 = 1;
264 for (i = b-1; i >= wpos2; i--)
265 {
266 wvalue2 <<= 1;
267 if (BN_is_bit_set(p2, i))
268 wvalue2++;
269 }
172 } 270 }
271
272 if (wvalue1 && b == wpos1)
273 {
274 /* wvalue1 is odd and < 2^window1 */
275 if (!BN_mod_mul_montgomery(r,r,&(val1[wvalue1>>1]),mont,ctx))
276 goto err;
277 wvalue1 = 0;
278 r_is_one = 0;
279 }
173 280
174 /* wvalue will be an odd number < 2^window */ 281 if (wvalue2 && b == wpos2)
175 if (xvalue || yvalue)
176 { 282 {
177 if (!BN_mod_mul_montgomery(r,r,&(val[xvalue][yvalue]), 283 /* wvalue2 is odd and < 2^window2 */
178 mont,ctx)) goto err; 284 if (!BN_mod_mul_montgomery(r,r,&(val2[wvalue2>>1]),mont,ctx))
285 goto err;
286 wvalue2 = 0;
287 r_is_one = 0;
179 } 288 }
180
181 /* move the 'window' down further */
182 wstart-=i;
183 start=0;
184 if (wstart < 0) break;
185 } 289 }
186 BN_from_montgomery(rr,r,mont,ctx); 290 BN_from_montgomery(rr,r,mont,ctx);
187 ret=1; 291 ret=1;
188err: 292err:
189 if ((in_mont == NULL) && (mont != NULL)) BN_MONT_CTX_free(mont); 293 if ((in_mont == NULL) && (mont != NULL)) BN_MONT_CTX_free(mont);
190 BN_CTX_end(ctx); 294 BN_CTX_end(ctx);
191 for (i=0; i<ts; i++) 295 for (i=0; i<ts1; i++)
192 { 296 BN_clear_free(&(val1[i]));
193 for (j=0; j<ts; j++) 297 for (i=0; i<ts2; i++)
194 { 298 BN_clear_free(&(val2[i]));
195 BN_clear_free(&(val[i][j]));
196 }
197 }
198 return(ret); 299 return(ret);
199 } 300 }
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