You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
159 lines
7.5 KiB
159 lines
7.5 KiB
4 months ago
|
/* 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) 1998-2006 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 "internal.h"
|
||
|
|
#include "../../internal.h"
|
||
|
|
|
||
|
|
#include "../../limbs/limbs.h"
|
||
|
|
#include "../../limbs/limbs.inl"
|
||
|
|
|
||
|
|
OPENSSL_STATIC_ASSERT(BN_MONT_CTX_N0_LIMBS == 1 || BN_MONT_CTX_N0_LIMBS == 2,
|
||
|
|
"BN_MONT_CTX_N0_LIMBS value is invalid");
|
||
|
|
OPENSSL_STATIC_ASSERT(
|
||
|
|
sizeof(BN_ULONG) * BN_MONT_CTX_N0_LIMBS == sizeof(uint64_t),
|
||
|
|
"uint64_t is insufficient precision for n0");
|
||
|
|
|
||
|
|
int GFp_bn_from_montgomery_in_place(BN_ULONG r[], size_t num_r, BN_ULONG a[],
|
||
|
|
size_t num_a, const BN_ULONG n[],
|
||
|
|
size_t num_n,
|
||
|
|
const BN_ULONG n0_[BN_MONT_CTX_N0_LIMBS]) {
|
||
|
|
if (num_n == 0 || num_r != num_n || num_a != 2 * num_n) {
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
// Add multiples of |n| to |r| until R = 2^(nl * BN_BITS2) divides it. On
|
||
|
|
// input, we had |r| < |n| * R, so now |r| < 2 * |n| * R. Note that |r|
|
||
|
|
// includes |carry| which is stored separately.
|
||
|
|
BN_ULONG n0 = n0_[0];
|
||
|
|
BN_ULONG carry = 0;
|
||
|
|
for (size_t i = 0; i < num_n; i++) {
|
||
|
|
BN_ULONG v = GFp_limbs_mul_add_limb(a + i, n, a[i] * n0, num_n);
|
||
|
|
v += carry + a[i + num_n];
|
||
|
|
carry |= (v != a[i + num_n]);
|
||
|
|
carry &= (v <= a[i + num_n]);
|
||
|
|
a[i + num_n] = v;
|
||
|
|
}
|
||
|
|
|
||
|
|
// Shift |num_n| words to divide by R. We have |a| < 2 * |n|. Note that |a|
|
||
|
|
// includes |carry| which is stored separately.
|
||
|
|
a += num_n;
|
||
|
|
|
||
|
|
// |a| thus requires at most one additional subtraction |n| to be reduced.
|
||
|
|
// Subtract |n| and select the answer in constant time.
|
||
|
|
BN_ULONG v = limbs_sub(r, a, n, num_n) - carry;
|
||
|
|
// |v| is one if |a| - |n| underflowed or zero if it did not. Note |v| cannot
|
||
|
|
// be -1. That would imply the subtraction did not fit in |num_n| words, and
|
||
|
|
// we know at most one subtraction is needed.
|
||
|
|
v = 0u - v;
|
||
|
|
for (size_t i = 0; i < num_n; i++) {
|
||
|
|
r[i] = constant_time_select_w(v, a[i], r[i]);
|
||
|
|
a[i] = 0;
|
||
|
|
}
|
||
|
|
return 1;
|
||
|
|
}
|