Commit 1df2957f authored by Niels Möller's avatar Niels Möller

New function _eddsa_expand_key.

parent 77d1f21f
2014-10-08 Niels Möller <nisse@lysator.liu.se>
* eddsa-expand.c (_eddsa_expand_key): New file, new function.
* eddsa.h (_eddsa_expand_key): Declare it.
* Makefile.in (hogweed_SOURCES): Added eddsa-expand.c.
* eddsa-sign.c: Drop unneeded include of nettle-internal.h.
2014-10-04 Niels Möller <nisse@lysator.liu.se>
......
......@@ -176,8 +176,8 @@ hogweed_SOURCES = sexp.c sexp-format.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-eh-to-x.c \
eddsa-compress.c eddsa-decompress.c eddsa-hash.c \
eddsa-sign.c \
eddsa-compress.c eddsa-decompress.c eddsa-expand.c \
eddsa-hash.c eddsa-sign.c \
$(OPT_HOGWEED_SOURCES)
HEADERS = aes.h arcfour.h arctwo.h asn1.h blowfish.h \
......
/* eddsa-expand.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 <assert.h>
#include <string.h>
#include "eddsa.h"
#include "ecc.h"
#include "ecc-internal.h"
#include "nettle-meta.h"
mp_size_t
_eddsa_expand_key_itch (const struct ecc_curve *ecc)
{
assert (_eddsa_compress_itch (ecc) <= ecc->mul_g_itch);
return 3*ecc->p.size + ecc->mul_g_itch;
}
/* Expands a private key, generating the key K1 for nonce generation,
the secret scalar K2, and, if PUB is non-NULL, the corresponding
public key (in compressed form). */
void
_eddsa_expand_key (const struct ecc_curve *ecc,
const struct nettle_hash *H,
void *ctx,
const uint8_t *key,
uint8_t *pub,
uint8_t *k1,
mp_limb_t *k2,
mp_limb_t *scratch)
{
size_t nbytes = 1 + ecc->p.bit_size / 8;
uint8_t *digest = (uint8_t *) scratch;
#define P scratch
#define scratch_out (scratch + 3*ecc->p.size)
assert (H->digest_size >= 2*nbytes);
H->init (ctx);
H->update (ctx, nbytes, key);
H->digest (ctx, 2*nbytes, digest);
memcpy (k1, digest + nbytes, nbytes);
mpn_set_base256_le (k2, ecc->p.size, digest, nbytes);
/* Clear low 3 bits */
k2[0] &= ~(mp_limb_t) 7;
/* Set bit number bit_size - 1 (bit 254 for curve25519) */
k2[(ecc->p.bit_size - 1) / GMP_NUMB_BITS]
|= (mp_limb_t) 1 << ((ecc->p.bit_size - 1) % GMP_NUMB_BITS);
/* Clear any higher bits. */
k2[ecc->p.size - 1] &= ~(mp_limb_t) 0
>> (GMP_NUMB_BITS * ecc->p.size - ecc->p.bit_size);
if (pub)
{
ecc->mul_g (ecc, P, k2, scratch_out);
_eddsa_compress (ecc, pub, P, scratch_out);
}
#undef P
#undef scratch_out
}
......@@ -46,6 +46,8 @@ extern "C" {
#define _eddsa_decompress _nettle_eddsa_decompress
#define _eddsa_decompress_itch _nettle_eddsa_decompress_itch
#define _eddsa_hash _nettle_eddsa_hash
#define _eddsa_expand_key_itch _nettle_eddsa_expand_key_itch
#define _eddsa_expand_key _nettle_eddsa_expand_key
#define _eddsa_sign _nettle_eddsa_sign
#define _eddsa_sign_itch _nettle_eddsa_sign_itch
......@@ -85,6 +87,20 @@ _eddsa_sign (const struct ecc_curve *ecc,
uint8_t *signature,
mp_limb_t *scratch);
mp_size_t
_eddsa_expand_key_itch (const struct ecc_curve *ecc);
void
_eddsa_expand_key (const struct ecc_curve *ecc,
const struct nettle_hash *H,
void *ctx,
const uint8_t *key,
uint8_t *pub,
uint8_t *k1,
mp_limb_t *k2,
mp_limb_t *scratch);
#ifdef __cplusplus
}
#endif
......
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