--- /dev/null
+/* crypto/bn/bn_exp2.c */
+/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
+ * All rights reserved.
+ *
+ * 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:
+ * 1. Redistributions of source code must retain the copyright
+ * 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 the
+ * documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ * must display the following acknowledgement:
+ * "This product includes cryptographic software written by
+ * 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
+ * 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
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * 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
+ * [including the GNU Public Licence.]
+ */
+/* ====================================================================
+ * Copyright (c) 1998-2000 The OpenSSL Project. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ * 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
+ * the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * 3. All advertising materials mentioning features or use of this
+ * software must display the following acknowledgment:
+ * "This product includes software developed by the OpenSSL Project
+ * for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
+ *
+ * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
+ * endorse or promote products derived from this software without
+ * prior written permission. For written permission, please contact
+ * openssl-core@openssl.org.
+ *
+ * 5. Products derived from this software may not be called "OpenSSL"
+ * nor may "OpenSSL" appear in their names without prior written
+ * permission of the OpenSSL Project.
+ *
+ * 6. Redistributions of any form whatsoever must retain the following
+ * acknowledgment:
+ * "This product includes software developed by the OpenSSL Project
+ * for use in the OpenSSL Toolkit (http://www.openssl.org/)"
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
+ * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
+ * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT 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.
+ * ====================================================================
+ *
+ * This product includes cryptographic software written by Eric Young
+ * (eay@cryptsoft.com). This product includes software written by Tim
+ * Hudson (tjh@cryptsoft.com).
+ *
+ */
+
+#include <stdio.h>
+#include "cryptlib.h"
+#include "bn_lcl.h"
+
+#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;
+
+ 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;
+ }
+
+ 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;
+
+ 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);
+
+ /*
+ * 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;
+
+ 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;
+ }
+ }
+
+
+ /* 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 (!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 (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);
+ }
projects / cassiopeia.git / blobdiff