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Dmitry Baryshkov
nettle
Commits
fd179ede
Commit
fd179ede
authored
Sep 02, 2014
by
Niels Möller
Browse files
New function curve25519_eh_to_x.
parent
2e24e947
Changes
6
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ChangeLog
View file @
fd179ede
2014-09-02 Niels Möller <nisse@lysator.liu.se>
* curve25519-eh-to-x.c (curve25519_eh_to_x): New file, new
function. The curve25519 transform currently done by ecc_eh_to_a,
but which should eventually be eliminted from that function.
* Makefile.in (hogweed_SOURCES): Added curve25519-eh-to-x.c.
* ecc-internal.h (curve25519_eh_to_x): Declare it.
* curve25519-mul.c (curve25519_mul): Use it.
* curve25519-mul-g.c (curve25519_mul_g): Likewise.
2014-08-29 Niels Möller <nisse@lysator.liu.se>
* testsuite/testutils.c (test_ecc_mul_j): Renamed, to ...
...
...
Makefile.in
View file @
fd179ede
...
...
@@ -174,7 +174,7 @@ hogweed_SOURCES = sexp.c sexp-format.c \
ecc-point.c ecc-scalar.c ecc-point-mul.c ecc-point-mul-g.c
\
ecc-ecdsa-sign.c ecdsa-sign.c
\
ecc-ecdsa-verify.c ecdsa-verify.c ecdsa-keygen.c
\
curve25519-mul-g.c curve25519-mul.c
\
curve25519-mul-g.c curve25519-mul.c
curve25519-eh-to-x.c
\
$(OPT_HOGWEED_SOURCES)
HEADERS
=
aes.h arcfour.h arctwo.h asn1.h blowfish.h
\
...
...
curve25519-eh-to-x.c
0 → 100644
View file @
fd179ede
/* curve25519-x.c
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
<string.h>
#include
"curve25519.h"
#include
"ecc.h"
#include
"ecc-internal.h"
/* Transform a point on the twisted Edwards curve to the curve25519
Montgomery curve, and return the x coordinate. */
void
curve25519_eh_to_x
(
mp_limb_t
*
xp
,
const
mp_limb_t
*
p
,
mp_limb_t
*
scratch
)
{
#define vp (p + ecc->size)
#define wp (p + 2*ecc->size)
#define t0 scratch
#define t1 (scratch + ecc->size)
#define t2 (scratch + 2*ecc->size)
const
struct
ecc_curve
*
ecc
=
&
nettle_curve25519
;
mp_limb_t
cy
;
/* If u = U/W and v = V/W are the coordiantes of the point on the
Edwards curve we get the curve25519 x coordinate as
x = (1+v) / (1-v) = (W + V) / (W - V)
*/
/* NOTE: For the infinity point, this subtraction gives zero (mod
p), which isn't invertible. For curve25519, the desired output is
x = 0, and we should be fine, since ecc_modp_inv returns 0
in this case. */
ecc_modp_sub
(
ecc
,
t0
,
wp
,
vp
);
/* Needs 3*size scratch, for a total of 5*size */
ecc_modp_inv
(
ecc
,
t1
,
t0
,
t2
);
ecc_modp_add
(
ecc
,
t0
,
wp
,
vp
);
ecc_modp_mul
(
ecc
,
t2
,
t0
,
t1
);
cy
=
mpn_sub_n
(
xp
,
t2
,
ecc
->
p
,
ecc
->
size
);
cnd_copy
(
cy
,
xp
,
t2
,
ecc
->
size
);
#undef vp
#undef wp
#undef t0
#undef t1
#undef t2
}
curve25519-mul-g.c
View file @
fd179ede
...
...
@@ -64,7 +64,7 @@ curve25519_mul_g (uint8_t *r, const uint8_t *n)
mpn_set_base256_le
(
x
,
ecc_size
,
t
,
CURVE25519_SIZE
);
ecc_mul_g_eh
(
&
nettle_curve25519
,
p
,
x
,
scratch_out
);
ecc_eh_to_a
(
&
nettle_curve25519
,
1
,
x
,
p
,
scratch_out
);
curve25519_eh_to_x
(
x
,
p
,
scratch_out
);
mpn_get_base256_le
(
r
,
CURVE25519_SIZE
,
x
,
ecc_size
);
gmp_free_limbs
(
scratch
,
itch
);
...
...
curve25519-mul.c
View file @
fd179ede
...
...
@@ -82,7 +82,7 @@ curve25519_mul (uint8_t *q, const uint8_t *n, const uint8_t *p)
mpn_set_base256_le
(
s
,
ecc
->
size
,
t
,
CURVE25519_SIZE
);
ecc_mul_a_eh
(
ecc
,
x
,
s
,
x
,
scratch_out
);
ecc
_eh_to_
a
(
ecc
,
1
,
s
,
x
,
scratch_out
);
curve25519
_eh_to_
x
(
s
,
x
,
scratch_out
);
mpn_get_base256_le
(
q
,
CURVE25519_SIZE
,
s
,
ecc
->
size
);
gmp_free_limbs
(
scratch
,
itch
);
...
...
ecc-internal.h
View file @
fd179ede
...
...
@@ -64,6 +64,7 @@
#define sec_tabselect _nettle_sec_tabselect
#define sec_modinv _nettle_sec_modinv
#define ecc_25519_sqrt _nettle_ecc_25519_sqrt
#define curve25519_eh_to_x _nettle_curve25519_eh_to_x
#define ECC_MAX_SIZE ((521 + GMP_NUMB_BITS - 1) / GMP_NUMB_BITS)
...
...
@@ -266,6 +267,10 @@ sec_modinv (mp_limb_t *vp, mp_limb_t *ap, mp_size_t n,
int
ecc_25519_sqrt
(
mp_limb_t
*
rp
,
const
mp_limb_t
*
ap
);
void
curve25519_eh_to_x
(
mp_limb_t
*
xp
,
const
mp_limb_t
*
p
,
mp_limb_t
*
scratch
);
/* Current scratch needs: */
#define ECC_MODINV_ITCH(size) (3*(size))
#define ECC_J_TO_A_ITCH(size) (5*(size))
...
...
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