Commit f064ef39 authored by Niels Möller's avatar Niels Möller

Split ecc_generic_redc into two functions ecc_pp1_redc and ecc_pm1_redc.

parent f5a43f62
2014-08-28 Niels Möller <nisse@lysator.liu.se>
* ecc-generic-redc.c (ecc_generic_redc): Deleted file and
function. Split into...
* ecc-pp1-redc.c (ecc_pp1_redc): New file and function.
* ecc-pm1-redc.c (ecc_pm1_redc): New file and function.
* ecc-internal.h: Updated declarations.
* Makefile.in (hogweed_SOURCES): Replace ecc-generic-redc.c by
ecc-pp1-redc.c and ecc-pm1-redc.c.
* ecc-192.c: Use ecc_pp1_redc (benchmarking only).
* ecc-224.c: Use ecc_pm1_redc when applicable.
* ecc-256.c: Use ecc_pp1_redc when applicable.
* ecc-384.c: Use ecc_pp1_redc (benchmarking only).
* ecc-521.c: Use ecc_pp1_redc (benchmarking only).
* testsuite/ecc-redc-test.c (test_main): Replace use of
ecc_generic_redc by ecc_pp1_redc and ecc_pm1_redc.
* eccdata.c (output_curve): Don't output ecc_redc_g.
* ecc-internal.h (struct ecc_curve): Deleted unused field redc_g.
Updated all instances.
......
......@@ -162,7 +162,7 @@ hogweed_SOURCES = sexp.c sexp-format.c \
sec-add-1.c sec-sub-1.c sec-modinv.c sec-tabselect.c \
gmp-glue.c cnd-copy.c \
ecc-mod.c ecc-generic-modp.c ecc-generic-modq.c \
ecc-modp.c ecc-modq.c ecc-generic-redc.c \
ecc-modp.c ecc-modq.c ecc-pp1-redc.c ecc-pm1-redc.c \
ecc-192.c ecc-224.c ecc-256.c ecc-384.c ecc-521.c \
ecc-25519.c \
ecc-size.c ecc-j-to-a.c ecc-a-to-j.c \
......
......@@ -127,7 +127,7 @@ const struct ecc_curve nettle_secp_192r1 =
ECC_J_TO_A_ITCH (ECC_LIMB_SIZE),
ecc_192_modp,
ecc_generic_redc,
ECC_REDC_SIZE >= 1 ? ecc_pp1_redc : NULL,
ecc_192_modp,
ecc_generic_modq,
......
......@@ -54,6 +54,14 @@ ecc_224_modp (const struct ecc_curve *ecc, mp_limb_t *rp);
#include "ecc-224.h"
#if ECC_REDC_SIZE < 0
# define ecc_224_redc ecc_pm1_redc
#elif ECC_REDC_SIZE == 0
# define ecc_224_redc NULL
#else
# error Configuration error
#endif
const struct ecc_curve nettle_secp_224r1 =
{
224,
......@@ -71,8 +79,8 @@ const struct ecc_curve nettle_secp_224r1 =
ECC_J_TO_A_ITCH (ECC_LIMB_SIZE),
ecc_224_modp,
ecc_generic_redc,
USE_REDC ? ecc_generic_redc : ecc_224_modp,
ecc_224_redc,
USE_REDC ? ecc_224_redc : ecc_224_modp,
ecc_generic_modq,
ecc_mul_a,
......
......@@ -55,8 +55,14 @@
void
ecc_256_redc (const struct ecc_curve *ecc, mp_limb_t *rp);
#else /* !HAVE_NATIVE_ecc_256_redc */
# define ecc_256_redc ecc_generic_redc
#endif
# if ECC_REDC_SIZE > 0
# define ecc_256_redc ecc_pp1_redc
# elif ECC_REDC_SIZE == 0
# define ecc_256_redc NULL
# else
# error Configuration error
# endif
#endif /* !HAVE_NATIVE_ecc_256_redc */
#if ECC_BMODP_SIZE < ECC_LIMB_SIZE
#define ecc_256_modp ecc_generic_modp
......
......@@ -164,7 +164,7 @@ const struct ecc_curve nettle_secp_384r1 =
ECC_J_TO_A_ITCH (ECC_LIMB_SIZE),
ecc_384_modp,
ECC_REDC_SIZE != 0 ? ecc_generic_redc : NULL,
ECC_REDC_SIZE > 0 ? ecc_pp1_redc : NULL,
ecc_384_modp,
ecc_generic_modq,
......
......@@ -92,7 +92,7 @@ const struct ecc_curve nettle_secp_521r1 =
ECC_J_TO_A_ITCH (ECC_LIMB_SIZE),
ecc_521_modp,
ecc_generic_redc,
ECC_REDC_SIZE > 0 ? ecc_pp1_redc : NULL,
ecc_521_modp,
ecc_generic_modq,
......
......@@ -41,7 +41,8 @@
/* Name mangling */
#define ecc_generic_modp _nettle_ecc_generic_modp
#define ecc_generic_redc _nettle_ecc_generic_redc
#define ecc_pp1_redc _nettle_ecc_pp1_redc
#define ecc_pm1_redc _nettle_ecc_pm1_redc
#define ecc_generic_modq _nettle_ecc_generic_modq
#define ecc_modp_add _nettle_ecc_modp_add
#define ecc_modp_sub _nettle_ecc_modp_sub
......@@ -174,7 +175,8 @@ struct ecc_curve
/* In-place reduction. */
ecc_mod_func ecc_generic_modp;
ecc_mod_func ecc_generic_redc;
ecc_mod_func ecc_pp1_redc;
ecc_mod_func ecc_pm1_redc;
ecc_mod_func ecc_generic_modq;
......
/* ecc-pm1-redc.c
Copyright (C) 2013, 2014 Niels Möller
This file is part of GNU Nettle.
GNU Nettle is free software: you can redistribute it and/or
modify it under the terms of either:
* the GNU Lesser General Public License as published by the Free
Software Foundation; either version 3 of the License, or (at your
option) any later version.
or
* the GNU General Public License as published by the Free
Software Foundation; either version 2 of the License, or (at your
option) any later version.
or both in parallel, as here.
GNU Nettle is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received copies of the GNU General Public License and
the GNU Lesser General Public License along with this program. If
not, see http://www.gnu.org/licenses/.
*/
/* Development of Nettle's ECC support was funded by the .SE Internet Fund. */
#if HAVE_CONFIG_H
# include "config.h"
#endif
#include <assert.h>
#include "ecc-internal.h"
/* Use that 1 = - (p - 1) (mod p), and that at least one low limb of p
- 1 is zero. */
void
ecc_pm1_redc (const struct ecc_curve *ecc, mp_limb_t *rp)
{
unsigned i;
mp_limb_t hi, cy;
unsigned shift = ecc->size * GMP_NUMB_BITS - ecc->bit_size;
mp_size_t k = -ecc->redc_size;
assert (k > 0);
for (i = 0; i < ecc->size; i++)
rp[i] = mpn_submul_1 (rp + i + k,
ecc->redc_ppm1, ecc->size - k, rp[i]);
hi = mpn_sub_n (rp, rp + ecc->size, rp, ecc->size);
cy = cnd_add_n (hi, rp, ecc->p, ecc->size);
assert (cy == hi);
if (shift > 0)
{
/* Result is always < 2p, provided that
2^shift * Bmodp_shifted <= p */
hi = (rp[ecc->size - 1] >> (GMP_NUMB_BITS - shift));
rp[ecc->size - 1] = (rp[ecc->size - 1]
& (((mp_limb_t) 1 << (GMP_NUMB_BITS - shift)) - 1))
+ mpn_addmul_1 (rp, ecc->Bmodp_shifted, ecc->size-1, hi);
}
}
/* ecc-generic-redc.c
/* ecc-pp1-redc.c
Copyright (C) 2013 Niels Möller
Copyright (C) 2013, 2014 Niels Möller
This file is part of GNU Nettle.
......@@ -39,56 +39,33 @@
#include "ecc-internal.h"
/* Use that 1 = p + 1 (mod p), and that at least one low limb of p + 1
is zero. */
void
ecc_generic_redc (const struct ecc_curve *ecc, mp_limb_t *rp)
ecc_pp1_redc (const struct ecc_curve *ecc, mp_limb_t *rp)
{
unsigned i;
mp_limb_t hi, cy;
unsigned shift = ecc->size * GMP_NUMB_BITS - ecc->bit_size;
mp_size_t k = ecc->redc_size;
assert (k != 0);
if (k > 0)
assert (k > 0);
for (i = 0; i < ecc->size; i++)
rp[i] = mpn_addmul_1 (rp + i + k,
ecc->redc_ppm1, ecc->size - k, rp[i]);
hi = mpn_add_n (rp, rp, rp + ecc->size, ecc->size);
if (shift > 0)
{
/* Use that 1 = p + 1, and that at least one low limb of p + 1 is zero. */
for (i = 0; i < ecc->size; i++)
rp[i] = mpn_addmul_1 (rp + i + k,
ecc->redc_ppm1, ecc->size - k, rp[i]);
hi = mpn_add_n (rp, rp, rp + ecc->size, ecc->size);
if (shift > 0)
{
hi = (hi << shift) | (rp[ecc->size - 1] >> (GMP_NUMB_BITS - shift));
rp[ecc->size - 1] = (rp[ecc->size - 1]
& (((mp_limb_t) 1 << (GMP_NUMB_BITS - shift)) - 1))
+ mpn_addmul_1 (rp, ecc->Bmodp_shifted, ecc->size-1, hi);
hi = (hi << shift) | (rp[ecc->size - 1] >> (GMP_NUMB_BITS - shift));
rp[ecc->size - 1] = (rp[ecc->size - 1]
& (((mp_limb_t) 1 << (GMP_NUMB_BITS - shift)) - 1))
+ mpn_addmul_1 (rp, ecc->Bmodp_shifted, ecc->size-1, hi);
}
else
{
cy = cnd_sub_n (hi, rp, ecc->p, ecc->size);
assert (cy == hi);
}
}
else
{
/* Use that 1 = - (p - 1), and that at least one low limb of p -
1 is zero. */
k = -k;
for (i = 0; i < ecc->size; i++)
rp[i] = mpn_submul_1 (rp + i + k,
ecc->redc_ppm1, ecc->size - k, rp[i]);
hi = mpn_sub_n (rp, rp + ecc->size, rp, ecc->size);
cy = cnd_add_n (hi, rp, ecc->p, ecc->size);
assert (cy == hi);
if (shift > 0)
{
/* Result is always < 2p, provided that
2^shift * Bmodp_shifted <= p */
hi = (rp[ecc->size - 1] >> (GMP_NUMB_BITS - shift));
rp[ecc->size - 1] = (rp[ecc->size - 1]
& (((mp_limb_t) 1 << (GMP_NUMB_BITS - shift)) - 1))
+ mpn_addmul_1 (rp, ecc->Bmodp_shifted, ecc->size-1, hi);
}
cy = cnd_sub_n (hi, rp, ecc->p, ecc->size);
assert (cy == hi);
}
}
......@@ -87,14 +87,18 @@ test_main (void)
}
mpn_copyi (m, a, 2*ecc->size);
ecc_generic_redc (ecc, m);
if (ecc->redc_size > 0)
ecc_pp1_redc (ecc, m);
else
ecc_pm1_redc (ecc, m);
if (mpn_cmp (m, ecc->p, ecc->size) >= 0)
mpn_sub_n (m, m, ecc->p, ecc->size);
if (mpn_cmp (m, ref, ecc->size))
{
fprintf (stderr, "ecc_generic_redc failed: bit_size = %u\n",
ecc->bit_size);
fprintf (stderr, "ecc_p%c1_redc failed: bit_size = %u\n",
ecc->redc_size > 0 ? 'p' : 'm', ecc->bit_size);
gmp_fprintf (stderr, "a = %Nx\n", a, 2*ecc->size);
gmp_fprintf (stderr, "m = %Nx (bad)\n", m, ecc->size);
gmp_fprintf (stderr, "ref = %Nx\n", ref, ecc->size);
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment