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-rw-r--r--crypto/bn/bn_exp2.c365
1 files changed, 178 insertions, 187 deletions
diff --git a/crypto/bn/bn_exp2.c b/crypto/bn/bn_exp2.c
index bd0c34b91b..43fd2044c0 100644
--- a/crypto/bn/bn_exp2.c
+++ b/crypto/bn/bn_exp2.c
@@ -5,21 +5,21 @@
* This package is an SSL implementation written
* by Eric Young (eay@cryptsoft.com).
* The implementation was written so as to conform with Netscapes SSL.
- *
+ *
* This library is free for commercial and non-commercial use as long as
* the following conditions are aheared to. The following conditions
* apply to all code found in this distribution, be it the RC4, RSA,
* lhash, DES, etc., code; not just the SSL code. The SSL documentation
* included with this distribution is covered by the same copyright terms
* except that the holder is Tim Hudson (tjh@cryptsoft.com).
- *
+ *
* Copyright remains Eric Young's, and as such any Copyright notices in
* the code are not to be removed.
* If this package is used in a product, Eric Young should be given attribution
* as the author of the parts of the library used.
* This can be in the form of a textual message at program startup or
* in documentation (online or textual) provided with the package.
- *
+ *
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
@@ -34,10 +34,10 @@
* Eric Young (eay@cryptsoft.com)"
* The word 'cryptographic' can be left out if the rouines from the library
* being used are not cryptographic related :-).
- * 4. If you include any Windows specific code (or a derivative thereof) from
+ * 4. If you include any Windows specific code (or a derivative thereof) from
* the apps directory (application code) you must include an acknowledgement:
* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
- *
+ *
* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
@@ -49,7 +49,7 @@
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
- *
+ *
* The licence and distribution terms for any publically available version or
* derivative of this code cannot be changed. i.e. this code cannot simply be
* copied and put under another distribution licence
@@ -63,7 +63,7 @@
* are met:
*
* 1. Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
+ * notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
@@ -113,200 +113,191 @@
#include "cryptlib.h"
#include "bn_lcl.h"
-#define TABLE_SIZE 32
+#define TABLE_SIZE 32
int BN_mod_exp2_mont(BIGNUM *rr, const BIGNUM *a1, const BIGNUM *p1,
- const BIGNUM *a2, const BIGNUM *p2, const BIGNUM *m,
- BN_CTX *ctx, BN_MONT_CTX *in_mont)
- {
- int i,j,bits,b,bits1,bits2,ret=0,wpos1,wpos2,window1,window2,wvalue1,wvalue2;
- int r_is_one=1;
- BIGNUM *d,*r;
- const BIGNUM *a_mod_m;
- /* Tables of variables obtained from 'ctx' */
- BIGNUM *val1[TABLE_SIZE], *val2[TABLE_SIZE];
- BN_MONT_CTX *mont=NULL;
+ const BIGNUM *a2, const BIGNUM *p2, const BIGNUM *m,
+ BN_CTX *ctx, BN_MONT_CTX *in_mont)
+{
+ int i, j, bits, b, bits1, bits2, ret =
+ 0, wpos1, wpos2, window1, window2, wvalue1, wvalue2;
+ int r_is_one = 1;
+ BIGNUM *d, *r;
+ const BIGNUM *a_mod_m;
+ /* Tables of variables obtained from 'ctx' */
+ BIGNUM *val1[TABLE_SIZE], *val2[TABLE_SIZE];
+ BN_MONT_CTX *mont = NULL;
+
+ bn_check_top(a1);
+ bn_check_top(p1);
+ bn_check_top(a2);
+ bn_check_top(p2);
+ bn_check_top(m);
+
+ if (!(m->d[0] & 1)) {
+ BNerr(BN_F_BN_MOD_EXP2_MONT, BN_R_CALLED_WITH_EVEN_MODULUS);
+ return (0);
+ }
+ bits1 = BN_num_bits(p1);
+ bits2 = BN_num_bits(p2);
+ if ((bits1 == 0) && (bits2 == 0)) {
+ ret = BN_one(rr);
+ return ret;
+ }
- bn_check_top(a1);
- bn_check_top(p1);
- bn_check_top(a2);
- bn_check_top(p2);
- bn_check_top(m);
+ bits = (bits1 > bits2) ? bits1 : bits2;
- if (!(m->d[0] & 1))
- {
- BNerr(BN_F_BN_MOD_EXP2_MONT,BN_R_CALLED_WITH_EVEN_MODULUS);
- return(0);
- }
- bits1=BN_num_bits(p1);
- bits2=BN_num_bits(p2);
- if ((bits1 == 0) && (bits2 == 0))
- {
- ret = BN_one(rr);
- return ret;
- }
-
- bits=(bits1 > bits2)?bits1:bits2;
+ BN_CTX_start(ctx);
+ d = BN_CTX_get(ctx);
+ r = BN_CTX_get(ctx);
+ val1[0] = BN_CTX_get(ctx);
+ val2[0] = BN_CTX_get(ctx);
+ if (!d || !r || !val1[0] || !val2[0])
+ goto err;
- BN_CTX_start(ctx);
- d = BN_CTX_get(ctx);
- r = BN_CTX_get(ctx);
- val1[0] = BN_CTX_get(ctx);
- val2[0] = BN_CTX_get(ctx);
- if(!d || !r || !val1[0] || !val2[0]) goto err;
+ if (in_mont != NULL)
+ mont = in_mont;
+ else {
+ if ((mont = BN_MONT_CTX_new()) == NULL)
+ goto err;
+ if (!BN_MONT_CTX_set(mont, m, ctx))
+ goto err;
+ }
- if (in_mont != NULL)
- mont=in_mont;
- else
- {
- if ((mont=BN_MONT_CTX_new()) == NULL) goto err;
- if (!BN_MONT_CTX_set(mont,m,ctx)) goto err;
- }
+ window1 = BN_window_bits_for_exponent_size(bits1);
+ window2 = BN_window_bits_for_exponent_size(bits2);
- window1 = BN_window_bits_for_exponent_size(bits1);
- window2 = BN_window_bits_for_exponent_size(bits2);
+ /*
+ * Build table for a1: val1[i] := a1^(2*i + 1) mod m for i = 0 .. 2^(window1-1)
+ */
+ if (a1->neg || BN_ucmp(a1, m) >= 0) {
+ if (!BN_mod(val1[0], a1, m, ctx))
+ goto err;
+ a_mod_m = val1[0];
+ } else
+ a_mod_m = a1;
+ if (BN_is_zero(a_mod_m)) {
+ BN_zero(rr);
+ ret = 1;
+ goto err;
+ }
- /*
- * Build table for a1: val1[i] := a1^(2*i + 1) mod m for i = 0 .. 2^(window1-1)
- */
- if (a1->neg || BN_ucmp(a1,m) >= 0)
- {
- if (!BN_mod(val1[0],a1,m,ctx))
- goto err;
- a_mod_m = val1[0];
- }
- else
- a_mod_m = a1;
- if (BN_is_zero(a_mod_m))
- {
- BN_zero(rr);
- ret = 1;
- goto err;
- }
+ if (!BN_to_montgomery(val1[0], a_mod_m, mont, ctx))
+ goto err;
+ if (window1 > 1) {
+ if (!BN_mod_mul_montgomery(d, val1[0], val1[0], mont, ctx))
+ goto err;
- if (!BN_to_montgomery(val1[0],a_mod_m,mont,ctx)) goto err;
- if (window1 > 1)
- {
- if (!BN_mod_mul_montgomery(d,val1[0],val1[0],mont,ctx)) goto err;
+ j = 1 << (window1 - 1);
+ for (i = 1; i < j; i++) {
+ if (((val1[i] = BN_CTX_get(ctx)) == NULL) ||
+ !BN_mod_mul_montgomery(val1[i], val1[i - 1], d, mont, ctx))
+ goto err;
+ }
+ }
- j=1<<(window1-1);
- for (i=1; i<j; i++)
- {
- if(((val1[i] = BN_CTX_get(ctx)) == NULL) ||
- !BN_mod_mul_montgomery(val1[i],val1[i-1],
- d,mont,ctx))
- goto err;
- }
- }
+ /*
+ * Build table for a2: val2[i] := a2^(2*i + 1) mod m for i = 0 .. 2^(window2-1)
+ */
+ if (a2->neg || BN_ucmp(a2, m) >= 0) {
+ if (!BN_mod(val2[0], a2, m, ctx))
+ goto err;
+ a_mod_m = val2[0];
+ } else
+ a_mod_m = a2;
+ if (BN_is_zero(a_mod_m)) {
+ BN_zero(rr);
+ ret = 1;
+ goto err;
+ }
+ if (!BN_to_montgomery(val2[0], a_mod_m, mont, ctx))
+ goto err;
+ if (window2 > 1) {
+ if (!BN_mod_mul_montgomery(d, val2[0], val2[0], mont, ctx))
+ goto err;
+ j = 1 << (window2 - 1);
+ for (i = 1; i < j; i++) {
+ if (((val2[i] = BN_CTX_get(ctx)) == NULL) ||
+ !BN_mod_mul_montgomery(val2[i], val2[i - 1], d, mont, ctx))
+ goto err;
+ }
+ }
- /*
- * Build table for a2: val2[i] := a2^(2*i + 1) mod m for i = 0 .. 2^(window2-1)
- */
- if (a2->neg || BN_ucmp(a2,m) >= 0)
- {
- if (!BN_mod(val2[0],a2,m,ctx))
- goto err;
- a_mod_m = val2[0];
- }
- else
- a_mod_m = a2;
- if (BN_is_zero(a_mod_m))
- {
- BN_zero(rr);
- ret = 1;
- goto err;
- }
- if (!BN_to_montgomery(val2[0],a_mod_m,mont,ctx)) goto err;
- if (window2 > 1)
- {
- if (!BN_mod_mul_montgomery(d,val2[0],val2[0],mont,ctx)) goto err;
+ /* Now compute the power product, using independent windows. */
+ r_is_one = 1;
+ wvalue1 = 0; /* The 'value' of the first window */
+ wvalue2 = 0; /* The 'value' of the second window */
+ wpos1 = 0; /* If wvalue1 > 0, the bottom bit of the
+ * first window */
+ wpos2 = 0; /* If wvalue2 > 0, the bottom bit of the
+ * second window */
- j=1<<(window2-1);
- for (i=1; i<j; i++)
- {
- if(((val2[i] = BN_CTX_get(ctx)) == NULL) ||
- !BN_mod_mul_montgomery(val2[i],val2[i-1],
- d,mont,ctx))
- goto err;
- }
- }
+ if (!BN_to_montgomery(r, BN_value_one(), mont, ctx))
+ goto err;
+ for (b = bits - 1; b >= 0; b--) {
+ if (!r_is_one) {
+ if (!BN_mod_mul_montgomery(r, r, r, mont, ctx))
+ goto err;
+ }
+ if (!wvalue1)
+ if (BN_is_bit_set(p1, b)) {
+ /*
+ * consider bits b-window1+1 .. b for this window
+ */
+ i = b - window1 + 1;
+ while (!BN_is_bit_set(p1, i)) /* works for i<0 */
+ i++;
+ wpos1 = i;
+ wvalue1 = 1;
+ for (i = b - 1; i >= wpos1; i--) {
+ wvalue1 <<= 1;
+ if (BN_is_bit_set(p1, i))
+ wvalue1++;
+ }
+ }
- /* Now compute the power product, using independent windows. */
- r_is_one=1;
- wvalue1=0; /* The 'value' of the first window */
- wvalue2=0; /* The 'value' of the second window */
- wpos1=0; /* If wvalue1 > 0, the bottom bit of the first window */
- wpos2=0; /* If wvalue2 > 0, the bottom bit of the second window */
+ if (!wvalue2)
+ if (BN_is_bit_set(p2, b)) {
+ /*
+ * consider bits b-window2+1 .. b for this window
+ */
+ i = b - window2 + 1;
+ while (!BN_is_bit_set(p2, i))
+ i++;
+ wpos2 = i;
+ wvalue2 = 1;
+ for (i = b - 1; i >= wpos2; i--) {
+ wvalue2 <<= 1;
+ if (BN_is_bit_set(p2, i))
+ wvalue2++;
+ }
+ }
- if (!BN_to_montgomery(r,BN_value_one(),mont,ctx)) goto err;
- for (b=bits-1; b>=0; b--)
- {
- if (!r_is_one)
- {
- if (!BN_mod_mul_montgomery(r,r,r,mont,ctx))
- goto err;
- }
-
- if (!wvalue1)
- if (BN_is_bit_set(p1, b))
- {
- /* consider bits b-window1+1 .. b for this window */
- i = b-window1+1;
- while (!BN_is_bit_set(p1, i)) /* works for i<0 */
- i++;
- wpos1 = i;
- wvalue1 = 1;
- for (i = b-1; i >= wpos1; i--)
- {
- wvalue1 <<= 1;
- if (BN_is_bit_set(p1, i))
- wvalue1++;
- }
- }
-
- if (!wvalue2)
- if (BN_is_bit_set(p2, b))
- {
- /* consider bits b-window2+1 .. b for this window */
- i = b-window2+1;
- while (!BN_is_bit_set(p2, i))
- i++;
- wpos2 = i;
- wvalue2 = 1;
- for (i = b-1; i >= wpos2; i--)
- {
- wvalue2 <<= 1;
- if (BN_is_bit_set(p2, i))
- wvalue2++;
- }
- }
+ if (wvalue1 && b == wpos1) {
+ /* wvalue1 is odd and < 2^window1 */
+ if (!BN_mod_mul_montgomery(r, r, val1[wvalue1 >> 1], mont, ctx))
+ goto err;
+ wvalue1 = 0;
+ r_is_one = 0;
+ }
- if (wvalue1 && b == wpos1)
- {
- /* wvalue1 is odd and < 2^window1 */
- if (!BN_mod_mul_montgomery(r,r,val1[wvalue1>>1],mont,ctx))
- goto err;
- wvalue1 = 0;
- r_is_one = 0;
- }
-
- if (wvalue2 && b == wpos2)
- {
- /* wvalue2 is odd and < 2^window2 */
- if (!BN_mod_mul_montgomery(r,r,val2[wvalue2>>1],mont,ctx))
- goto err;
- wvalue2 = 0;
- r_is_one = 0;
- }
- }
- if (!BN_from_montgomery(rr,r,mont,ctx))
- goto err;
- ret=1;
-err:
- if ((in_mont == NULL) && (mont != NULL)) BN_MONT_CTX_free(mont);
- BN_CTX_end(ctx);
- bn_check_top(rr);
- return(ret);
- }
+ if (wvalue2 && b == wpos2) {
+ /* wvalue2 is odd and < 2^window2 */
+ if (!BN_mod_mul_montgomery(r, r, val2[wvalue2 >> 1], mont, ctx))
+ goto err;
+ wvalue2 = 0;
+ r_is_one = 0;
+ }
+ }
+ if (!BN_from_montgomery(rr, r, mont, ctx))
+ goto err;
+ ret = 1;
+ err:
+ if ((in_mont == NULL) && (mont != NULL))
+ BN_MONT_CTX_free(mont);
+ BN_CTX_end(ctx);
+ bn_check_top(rr);
+ return (ret);
+}
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