Commit 51a22f02 authored by Niels Möller's avatar Niels Möller

Implemented the curve25519 modp function.

parent 3396725b
2014-07-04 Niels Möller <nisse@lysator.liu.se>
* ecc-25519.c: New file.
(ecc_25519_modp): New function.
(nettle_curve25519): New curve.
* ecc-curve.h (nettle_curve25519): Declare it.
* Makefile.in (hogweed_SOURCES): Added ecc-25519.c.
(ecc-25519.h): New generated file. Add as explicit dependency for
ecc-25519.o.
* testsuite/ecc-mod-test.c (test_curve): New function, extracted
from test_main. Tolerate NULL modq function pointer.
(test_main): Use test_curve, iterate over supported curves, and
also test curve_25519 for the new modp function.
2014-07-02 Niels Möller <nisse@lysator.liu.se>
* eccdata.c (ecc_dup): Use mpz_submul_ui, now available in
......
......@@ -164,6 +164,7 @@ hogweed_SOURCES = sexp.c sexp-format.c \
ecc-mod.c ecc-generic-modp.c ecc-generic-modq.c \
ecc-modp.c ecc-modq.c ecc-generic-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 \
ecc-dup-jj.c ecc-add-jja.c ecc-add-jjj.c \
ecc-mul-g.c ecc-mul-a.c ecc-hash.c ecc-random.c \
......@@ -347,6 +348,9 @@ ecc-384.h: eccdata.stamp
ecc-521.h: eccdata.stamp
./eccdata$(EXEEXT_FOR_BUILD) 521 56 6 $(GMP_NUMB_BITS) > $@T && mv $@T $@
ecc-25519.h: eccdata.stamp
./eccdata$(EXEEXT_FOR_BUILD) 255 14 6 $(GMP_NUMB_BITS) > $@T && mv $@T $@
eccdata.stamp: eccdata.c
$(MAKE) eccdata$(EXEEXT_FOR_BUILD)
echo stamp > eccdata.stamp
......@@ -356,12 +360,14 @@ ecc-224.$(OBJEXT): ecc-224.h
ecc-256.$(OBJEXT): ecc-256.h
ecc-384.$(OBJEXT): ecc-384.h
ecc-521.$(OBJEXT): ecc-521.h
ecc-25519.$(OBJEXT): ecc-25519.h
ecc-192.p$(OBJEXT): ecc-192.h
ecc-224.p$(OBJEXT): ecc-224.h
ecc-256.p$(OBJEXT): ecc-256.h
ecc-384.p$(OBJEXT): ecc-384.h
ecc-521.p$(OBJEXT): ecc-521.h
ecc-25519.p$(OBJEXT): ecc-25519.h
.asm.s: $(srcdir)/asm.m4 machine.m4 config.m4
$(M4) $(srcdir)/asm.m4 machine.m4 config.m4 $< >$@T \
......
/* ecc-25519
Arithmetic and tables for curve25519,
Copyright (C) 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/.
*/
#if HAVE_CONFIG_H
# include "config.h"
#endif
#include "ecc-internal.h"
#define USE_REDC 0
#include "ecc-25519.h"
#define HIGH_BITS (GMP_NUMB_BITS * ECC_LIMB_SIZE - 255)
#if HIGH_BITS == 0
#error Unsupported limb size */
#endif
static void
ecc_25519_modp(const struct ecc_curve *ecc UNUSED, mp_limb_t *rp)
{
mp_limb_t hi, cy;
cy = mpn_addmul_1 (rp, rp + ECC_LIMB_SIZE, ECC_LIMB_SIZE,
(mp_limb_t) 19 << HIGH_BITS);
hi = rp[ECC_LIMB_SIZE-1];
cy = (cy << HIGH_BITS) + (hi >> (GMP_NUMB_BITS - HIGH_BITS));
rp[ECC_LIMB_SIZE-1] = (hi & (GMP_NUMB_MASK >> HIGH_BITS))
+ sec_add_1 (rp, rp, ECC_LIMB_SIZE - 1, 19 * cy);
}
const struct ecc_curve nettle_curve25519 =
{
255,
ECC_LIMB_SIZE,
ECC_BMODP_SIZE,
ECC_BMODQ_SIZE,
0, /* No redc */
0,
ECC_PIPPENGER_K,
ECC_PIPPENGER_C,
ecc_p,
ecc_b,
ecc_q,
ecc_g,
ecc_redc_g,
ecc_25519_modp,
NULL,
ecc_25519_modp,
NULL,
ecc_Bmodp,
ecc_Bmodp_shifted,
ecc_pp1h,
ecc_redc_ppm1,
ecc_unit,
ecc_Bmodq,
ecc_Bmodq_shifted,
ecc_qp1h,
ecc_table
};
......@@ -46,6 +46,7 @@ extern const struct ecc_curve nettle_secp_224r1;
extern const struct ecc_curve nettle_secp_256r1;
extern const struct ecc_curve nettle_secp_384r1;
extern const struct ecc_curve nettle_secp_521r1;
extern const struct ecc_curve nettle_curve25519;
#ifdef __cplusplus
}
......
......@@ -529,8 +529,10 @@ ecc_curve_init (struct ecc_curve *ecc, unsigned bit_size)
"7fffffffffffffffffffffffffffffff"
"ffffffffffffffffffffffffffffffed",
"76d06",
/* Order of the subgroup is 2^252 +
27742317777372353535851937790883648493 */
/* Order of the subgroup is 2^252 + q_0, where
q_0 = 27742317777372353535851937790883648493,
125 bits.
*/
"10000000000000000000000000000000"
"14def9dea2f79cd65812631a5cf5d3ed",
"9",
......
......@@ -19,70 +19,65 @@ ref_mod (mp_limb_t *rp, const mp_limb_t *ap, const mp_limb_t *mp, mp_size_t mn)
#define MAX_SIZE (2*MAX_ECC_SIZE)
#define COUNT 50000
void
test_main (void)
static void
test_curve (gmp_randstate_t rands, const struct ecc_curve *ecc)
{
gmp_randstate_t rands;
mp_limb_t a[MAX_SIZE];
mp_limb_t m[MAX_SIZE];
mp_limb_t ref[MAX_SIZE];
unsigned i;
mpz_t r;
unsigned j;
gmp_randinit_default (rands);
mpz_init (r);
for (i = 0; ecc_curves[i]; i++)
for (j = 0; j < COUNT; j++)
{
const struct ecc_curve *ecc = ecc_curves[i];
unsigned j;
for (j = 0; j < COUNT; j++)
{
if (j & 1)
mpz_rrandomb (r, rands, 2*ecc->size * GMP_NUMB_BITS);
else
mpz_urandomb (r, rands, 2*ecc->size * GMP_NUMB_BITS);
if (j & 1)
mpz_rrandomb (r, rands, 2*ecc->size * GMP_NUMB_BITS);
else
mpz_urandomb (r, rands, 2*ecc->size * GMP_NUMB_BITS);
mpz_limbs_copy (a, r, 2*ecc->size);
ref_mod (ref, a, ecc->p, ecc->size);
mpz_limbs_copy (a, r, 2*ecc->size);
mpn_copyi (m, a, 2*ecc->size);
ecc->modp (ecc, m);
if (mpn_cmp (m, ecc->p, ecc->size) >= 0)
mpn_sub_n (m, m, ecc->p, ecc->size);
ref_mod (ref, a, ecc->p, ecc->size);
if (mpn_cmp (m, ref, ecc->size))
{
fprintf (stderr, "ecc->modp failed: bit_size = %u\n",
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);
abort ();
}
if (ecc->Bmodp_size < ecc->size)
{
mpn_copyi (m, a, 2*ecc->size);
ecc->modp (ecc, m);
ecc_generic_modp (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->modp failed: bit_size = %u\n",
fprintf (stderr, "ecc_generic_modp failed: bit_size = %u\n",
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);
abort ();
}
}
if (ecc->Bmodp_size < ecc->size)
{
mpn_copyi (m, a, 2*ecc->size);
ecc_generic_modp (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_modp failed: bit_size = %u\n",
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);
abort ();
}
}
ref_mod (ref, a, ecc->q, ecc->size);
ref_mod (ref, a, ecc->q, ecc->size);
if (ecc->modq)
{
mpn_copyi (m, a, 2*ecc->size);
ecc->modq (ecc, m);
if (mpn_cmp (m, ecc->q, ecc->size) >= 0)
......@@ -97,28 +92,40 @@ test_main (void)
gmp_fprintf (stderr, "ref = %Nx\n", ref, ecc->size);
abort ();
}
}
if (ecc->Bmodq_size < ecc->size)
{
mpn_copyi (m, a, 2*ecc->size);
ecc_generic_modq (ecc, m);
if (mpn_cmp (m, ecc->q, ecc->size) >= 0)
mpn_sub_n (m, m, ecc->q, ecc->size);
if (ecc->Bmodq_size < ecc->size)
if (mpn_cmp (m, ref, ecc->size))
{
mpn_copyi (m, a, 2*ecc->size);
ecc_generic_modq (ecc, m);
if (mpn_cmp (m, ecc->q, ecc->size) >= 0)
mpn_sub_n (m, m, ecc->q, ecc->size);
if (mpn_cmp (m, ref, ecc->size))
{
fprintf (stderr, "ecc_generic_modp failed: bit_size = %u\n",
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);
abort ();
}
fprintf (stderr, "ecc_generic_modp failed: bit_size = %u\n",
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);
abort ();
}
}
}
mpz_clear (r);
}
void
test_main (void)
{
gmp_randstate_t rands;
unsigned i;
gmp_randinit_default (rands);
for (i = 0; ecc_curves[i]; i++)
test_curve (rands, ecc_curves[i]);
test_curve (rands, &nettle_curve25519);
gmp_randclear (rands);
}
#endif /* ! NETTLE_USE_MINI_GMP */
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