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Diffstat (limited to 'src/lib/libcrypto/bn/bn_exp2.c')
-rw-r--r--src/lib/libcrypto/bn/bn_exp2.c382
1 files changed, 250 insertions, 132 deletions
diff --git a/src/lib/libcrypto/bn/bn_exp2.c b/src/lib/libcrypto/bn/bn_exp2.c
index 1132d53365..73ccd58a83 100644
--- a/src/lib/libcrypto/bn/bn_exp2.c
+++ b/src/lib/libcrypto/bn/bn_exp2.c
@@ -1,27 +1,129 @@
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 improvment 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, const BIGNUM *a1, const BIGNUM *p1,
19 BIGNUM *p2, BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *in_mont) 119 const BIGNUM *a2, const BIGNUM *p2, const BIGNUM *m,
120 BN_CTX *ctx, BN_MONT_CTX *in_mont)
20 { 121 {
21 int i,j,k,bits,bits1,bits2,ret=0,wstart,wend,window,xvalue,yvalue; 122 int i,j,bits,b,bits1,bits2,ret=0,wpos1,wpos2,window1,window2,wvalue1,wvalue2;
22 int start=1,ts=0,x,y; 123 int r_is_one=1,ts1=0,ts2=0;
23 BIGNUM *d,*aa1,*aa2,*r; 124 BIGNUM *d,*r;
24 BIGNUM val[EXP2_TABLE_SIZE][EXP2_TABLE_SIZE]; 125 const BIGNUM *a_mod_m;
126 BIGNUM val1[TABLE_SIZE], val2[TABLE_SIZE];
25 BN_MONT_CTX *mont=NULL; 127 BN_MONT_CTX *mont=NULL;
26 128
27 bn_check_top(a1); 129 bn_check_top(a1);
@@ -32,22 +134,23 @@ int BN_mod_exp2_mont(BIGNUM *rr, BIGNUM *a1, BIGNUM *p1, BIGNUM *a2,
32 134
33 if (!(m->d[0] & 1)) 135 if (!(m->d[0] & 1))
34 { 136 {
35 BNerr(BN_F_BN_MOD_EXP_MONT,BN_R_CALLED_WITH_EVEN_MODULUS); 137 BNerr(BN_F_BN_MOD_EXP2_MONT,BN_R_CALLED_WITH_EVEN_MODULUS);
36 return(0); 138 return(0);
37 } 139 }
38 d= &(ctx->bn[ctx->tos++]);
39 r= &(ctx->bn[ctx->tos++]);
40 bits1=BN_num_bits(p1); 140 bits1=BN_num_bits(p1);
41 bits2=BN_num_bits(p2); 141 bits2=BN_num_bits(p2);
42 if ((bits1 == 0) && (bits2 == 0)) 142 if ((bits1 == 0) && (bits2 == 0))
43 { 143 {
44 BN_one(r); 144 ret = BN_one(rr);
45 return(1); 145 return ret;
46 } 146 }
147
47 bits=(bits1 > bits2)?bits1:bits2; 148 bits=(bits1 > bits2)?bits1:bits2;
48 149
49 /* If this is not done, things will break in the montgomery 150 BN_CTX_start(ctx);
50 * part */ 151 d = BN_CTX_get(ctx);
152 r = BN_CTX_get(ctx);
153 if (d == NULL || r == NULL) goto err;
51 154
52 if (in_mont != NULL) 155 if (in_mont != NULL)
53 mont=in_mont; 156 mont=in_mont;
@@ -57,139 +160,154 @@ int BN_mod_exp2_mont(BIGNUM *rr, BIGNUM *a1, BIGNUM *p1, BIGNUM *a2,
57 if (!BN_MONT_CTX_set(mont,m,ctx)) goto err; 160 if (!BN_MONT_CTX_set(mont,m,ctx)) goto err;
58 } 161 }
59 162
60 BN_init(&(val[0][0])); 163 window1 = BN_window_bits_for_exponent_size(bits1);
61 BN_init(&(val[1][1])); 164 window2 = BN_window_bits_for_exponent_size(bits2);
62 BN_init(&(val[0][1])); 165
63 BN_init(&(val[1][0])); 166 /*
64 ts=1; 167 * Build table for a1: val1[i] := a1^(2*i + 1) mod m for i = 0 .. 2^(window1-1)
65 if (BN_ucmp(a1,m) >= 0) 168 */
169 BN_init(&val1[0]);
170 ts1=1;
171 if (a1->neg || BN_ucmp(a1,m) >= 0)
66 { 172 {
67 BN_mod(&(val[1][0]),a1,m,ctx); 173 if (!BN_mod(&(val1[0]),a1,m,ctx))
68 aa1= &(val[1][0]); 174 goto err;
175 a_mod_m = &(val1[0]);
69 } 176 }
70 else 177 else
71 aa1=a1; 178 a_mod_m = a1;
72 if (BN_ucmp(a2,m) >= 0) 179 if (BN_is_zero(a_mod_m))
73 { 180 {
74 BN_mod(&(val[0][1]),a2,m,ctx); 181 ret = BN_zero(rr);
75 aa2= &(val[0][1]);
76 }
77 else
78 aa2=a2;
79 if (!BN_to_montgomery(&(val[1][0]),aa1,mont,ctx)) goto err;
80 if (!BN_to_montgomery(&(val[0][1]),aa2,mont,ctx)) goto err;
81 if (!BN_mod_mul_montgomery(&(val[1][1]),
82 &(val[1][0]),&(val[0][1]),mont,ctx))
83 goto err; 182 goto err;
183 }
84 184
85#if 0 185 if (!BN_to_montgomery(&(val1[0]),a_mod_m,mont,ctx)) goto err;
86 if (bits <= 20) /* This is probably 3 or 0x10001, so just do singles */ 186 if (window1 > 1)
87 window=1;
88 else if (bits > 250)
89 window=5; /* max size of window */
90 else if (bits >= 120)
91 window=4;
92 else
93 window=3;
94#else
95 window=EXP2_TABLE_BITS;
96#endif
97
98 k=1<<window;
99 for (x=0; x<k; x++)
100 { 187 {
101 if (x >= 2) 188 if (!BN_mod_mul_montgomery(d,&(val1[0]),&(val1[0]),mont,ctx)) goto err;
189
190 j=1<<(window1-1);
191 for (i=1; i<j; i++)
102 { 192 {
103 BN_init(&(val[x][0])); 193 BN_init(&(val1[i]));
104 BN_init(&(val[x][1])); 194 if (!BN_mod_mul_montgomery(&(val1[i]),&(val1[i-1]),d,mont,ctx))
105 if (!BN_mod_mul_montgomery(&(val[x][0]), 195 goto err;
106 &(val[1][0]),&(val[x-1][0]),mont,ctx)) goto err;
107 if (!BN_mod_mul_montgomery(&(val[x][1]),
108 &(val[1][0]),&(val[x-1][1]),mont,ctx)) goto err;
109 } 196 }
110 for (y=2; y<k; y++) 197 ts1=i;
198 }
199
200
201 /*
202 * Build table for a2: val2[i] := a2^(2*i + 1) mod m for i = 0 .. 2^(window2-1)
203 */
204 BN_init(&val2[0]);
205 ts2=1;
206 if (a2->neg || BN_ucmp(a2,m) >= 0)
207 {
208 if (!BN_mod(&(val2[0]),a2,m,ctx))
209 goto err;
210 a_mod_m = &(val2[0]);
211 }
212 else
213 a_mod_m = a2;
214 if (BN_is_zero(a_mod_m))
215 {
216 ret = BN_zero(rr);
217 goto err;
218 }
219 if (!BN_to_montgomery(&(val2[0]),a_mod_m,mont,ctx)) goto err;
220 if (window2 > 1)
221 {
222 if (!BN_mod_mul_montgomery(d,&(val2[0]),&(val2[0]),mont,ctx)) goto err;
223
224 j=1<<(window2-1);
225 for (i=1; i<j; i++)
111 { 226 {
112 BN_init(&(val[x][y])); 227 BN_init(&(val2[i]));
113 if (!BN_mod_mul_montgomery(&(val[x][y]), 228 if (!BN_mod_mul_montgomery(&(val2[i]),&(val2[i-1]),d,mont,ctx))
114 &(val[x][y-1]),&(val[0][1]),mont,ctx))
115 goto err; 229 goto err;
116 } 230 }
231 ts2=i;
117 } 232 }
118 ts=k; 233
119 234
120 start=1; /* This is used to avoid multiplication etc 235 /* Now compute the power product, using independent windows. */
121 * when there is only the value '1' in the 236 r_is_one=1;
122 * buffer. */ 237 wvalue1=0; /* The 'value' of the first window */
123 xvalue=0; /* The 'x value' of the window */ 238 wvalue2=0; /* The 'value' of the second window */
124 yvalue=0; /* The 'y value' of the window */ 239 wpos1=0; /* If wvalue1 > 0, the bottom bit of the first window */
125 wstart=bits-1; /* The top bit of the window */ 240 wpos2=0; /* If wvalue2 > 0, the bottom bit of the second window */
126 wend=0; /* The bottom bit of the window */ 241
127 242 if (!BN_to_montgomery(r,BN_value_one(),mont,ctx)) goto err;
128 if (!BN_to_montgomery(r,BN_value_one(),mont,ctx)) goto err; 243 for (b=bits-1; b>=0; b--)
129 for (;;)
130 { 244 {
131 xvalue=BN_is_bit_set(p1,wstart); 245 if (!r_is_one)
132 yvalue=BN_is_bit_set(p2,wstart);
133 if (!(xvalue || yvalue))
134 { 246 {
135 if (!start) 247 if (!BN_mod_mul_montgomery(r,r,r,mont,ctx))
248 goto err;
249 }
250
251 if (!wvalue1)
252 if (BN_is_bit_set(p1, b))
136 { 253 {
137 if (!BN_mod_mul_montgomery(r,r,r,mont,ctx)) 254 /* consider bits b-window1+1 .. b for this window */
138 goto err; 255 i = b-window1+1;
256 while (!BN_is_bit_set(p1, i)) /* works for i<0 */
257 i++;
258 wpos1 = i;
259 wvalue1 = 1;
260 for (i = b-1; i >= wpos1; i--)
261 {
262 wvalue1 <<= 1;
263 if (BN_is_bit_set(p1, i))
264 wvalue1++;
265 }
139 } 266 }
140 wstart--; 267
141 if (wstart < 0) break; 268 if (!wvalue2)
142 continue; 269 if (BN_is_bit_set(p2, b))
143 }
144 /* We now have wstart on a 'set' bit, we now need to work out
145 * how bit a window to do. To do this we need to scan
146 * forward until the last set bit before the end of the
147 * window */
148 j=wstart;
149 /* xvalue=BN_is_bit_set(p1,wstart); already set */
150 /* yvalue=BN_is_bit_set(p1,wstart); already set */
151 wend=0;
152 for (i=1; i<window; i++)
153 {
154 if (wstart-i < 0) break;
155 xvalue+=xvalue;
156 xvalue|=BN_is_bit_set(p1,wstart-i);
157 yvalue+=yvalue;
158 yvalue|=BN_is_bit_set(p2,wstart-i);
159 }
160
161 /* i is the size of the current window */
162 /* add the 'bytes above' */
163 if (!start)
164 for (j=0; j<i; j++)
165 { 270 {
166 if (!BN_mod_mul_montgomery(r,r,r,mont,ctx)) 271 /* consider bits b-window2+1 .. b for this window */
167 goto err; 272 i = b-window2+1;
273 while (!BN_is_bit_set(p2, i))
274 i++;
275 wpos2 = i;
276 wvalue2 = 1;
277 for (i = b-1; i >= wpos2; i--)
278 {
279 wvalue2 <<= 1;
280 if (BN_is_bit_set(p2, i))
281 wvalue2++;
282 }
168 } 283 }
284
285 if (wvalue1 && b == wpos1)
286 {
287 /* wvalue1 is odd and < 2^window1 */
288 if (!BN_mod_mul_montgomery(r,r,&(val1[wvalue1>>1]),mont,ctx))
289 goto err;
290 wvalue1 = 0;
291 r_is_one = 0;
292 }
169 293
170 /* wvalue will be an odd number < 2^window */ 294 if (wvalue2 && b == wpos2)
171 if (xvalue || yvalue)
172 { 295 {
173 if (!BN_mod_mul_montgomery(r,r,&(val[xvalue][yvalue]), 296 /* wvalue2 is odd and < 2^window2 */
174 mont,ctx)) goto err; 297 if (!BN_mod_mul_montgomery(r,r,&(val2[wvalue2>>1]),mont,ctx))
298 goto err;
299 wvalue2 = 0;
300 r_is_one = 0;
175 } 301 }
176
177 /* move the 'window' down further */
178 wstart-=i;
179 start=0;
180 if (wstart < 0) break;
181 } 302 }
182 BN_from_montgomery(rr,r,mont,ctx); 303 BN_from_montgomery(rr,r,mont,ctx);
183 ret=1; 304 ret=1;
184err: 305err:
185 if ((in_mont == NULL) && (mont != NULL)) BN_MONT_CTX_free(mont); 306 if ((in_mont == NULL) && (mont != NULL)) BN_MONT_CTX_free(mont);
186 ctx->tos-=2; 307 BN_CTX_end(ctx);
187 for (i=0; i<ts; i++) 308 for (i=0; i<ts1; i++)
188 { 309 BN_clear_free(&(val1[i]));
189 for (j=0; j<ts; j++) 310 for (i=0; i<ts2; i++)
190 { 311 BN_clear_free(&(val2[i]));
191 BN_clear_free(&(val[i][j]));
192 }
193 }
194 return(ret); 312 return(ret);
195 } 313 }
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